Bump to 1.8.1 (88)

A .strings value may span several physical lines, so deleting such an
entry line by line leaves orphaned lines that the parser folds into the
preceding value. Every key behind that point then disappears at runtime
while plutil -lint still reports OK. Tab titles are looked up without a
defaultValue:, so the tab bar rendered raw keys like "tab.overview"
while the rest of the UI fell back to its English defaults.

LocalizationIntegrityTests parses each table out of the app bundle and
fails on multi-line values, on missing keys that have no fallback, and
on leftover cable.pro.* entries. LocalizedTabBarUITests launches the app
in German and asserts the tab bar is translated.

.gitignore

@@ -5,3 +5,14 @@ Vendor
 Shots/Framed
 Shots/Screenshots
 *.xcresult
+
+# Build products
+DerivedData*/
+build/
+*.ipa
+*.dSYM.zip
+*.xcuserstate
+*.xcuserdatad
+
+# Credentials
+PocketBase-LLM/pb-credentials.json

Cable.xcodeproj/project.pbxproj

@@ -418,7 +418,7 @@
 				CODE_SIGN_ENTITLEMENTS = Cable/Cable.entitlements;
 				CODE_SIGN_IDENTITY = "Apple Development";
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 87;
+				CURRENT_PROJECT_VERSION = 88;
 				DEVELOPMENT_TEAM = RE4FXQ754N;
 				ENABLE_APP_SANDBOX = YES;
 				ENABLE_PREVIEWS = YES;
@@ -436,7 +436,7 @@
 					"$(inherited)",
 					"@executable_path/Frameworks",
 				);
-				MARKETING_VERSION = 1.8.0;
+				MARKETING_VERSION = 1.8.1;
 				PRODUCT_BUNDLE_IDENTIFIER = app.voltplan.CableApp;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";
@@ -454,7 +454,7 @@
 				CODE_SIGN_ENTITLEMENTS = Cable/Cable.entitlements;
 				CODE_SIGN_IDENTITY = "Apple Development";
 				CODE_SIGN_STYLE = Automatic;
-				CURRENT_PROJECT_VERSION = 87;
+				CURRENT_PROJECT_VERSION = 88;
 				DEVELOPMENT_TEAM = RE4FXQ754N;
 				ENABLE_APP_SANDBOX = YES;
 				ENABLE_PREVIEWS = YES;
@@ -472,7 +472,7 @@
 					"$(inherited)",
 					"@executable_path/Frameworks",
 				);
-				MARKETING_VERSION = 1.8.0;
+				MARKETING_VERSION = 1.8.1;
 				PRODUCT_BUNDLE_IDENTIFIER = app.voltplan.CableApp;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				PROVISIONING_PROFILE_SPECIFIER = "";

Cable/Base.lproj/Localizable.strings

@@ -117,10 +117,6 @@
 "bom.quantity.terminal.badge" = "%1$d× · %2$@";
 "bom.quantity.cable.badge" = "%1$.1f %2$@ · %3$@";
 "bom.quantity.single.badge" = "1× • %@";
-"cable.pro.privacy.label" = "Privacy";
-"cable.pro.privacy.url" = "https://voltplan.app/privacy";
-"cable.pro.terms.label" = "Terms";
-"cable.pro.terms.url" = "https://voltplan.app/terms";
 "calculator.advanced.duty_cycle.helper" = "Percentage of each active session where the load actually draws power.";
 "calculator.advanced.duty_cycle.title" = "Duty Cycle";
 "calculator.advanced.section.title" = "Advanced Settings";
@@ -199,7 +195,7 @@
 "loads.overview.metric.current" = "Total Current";
 "loads.overview.metric.power" = "Total Power";
 "loads.overview.status.missing_details.banner" = "Finish configuring your loads";
-"loads.overview.status.missing_details.message" = "Enter cable length and wire size for %d %@ to see accurate recommendations.";
+"loads.overview.status.missing_details.message" = "Enter cable length and current draw for %d %@ so Cable can size the wiring.";
 "loads.overview.status.missing_details.plural" = "loads";
 "loads.overview.status.missing_details.singular" = "load";
 "loads.overview.status.missing_details.title" = "Missing load details";
@@ -289,47 +285,7 @@
 "settings.pro.manage.url" = "https://apps.apple.com/account/subscriptions";
 "settings.pro.day.one" = "%@ day";
 "settings.pro.day.other" = "%@ days";
-"cable.pro.terms.label" = "Terms";
-"cable.pro.privacy.label" = "Privacy";
-"cable.pro.terms.url" = "https://voltplan.app/terms";
-"cable.pro.privacy.url" = "https://voltplan.app/privacy";
-"cable.pro.paywall.title" = "Cable PRO";
-"cable.pro.paywall.subtitle" = "Cable PRO enables more configuration options for loads, batteries and chargers.";
-"cable.pro.feature.dutyCycle" = "Duty-cycle aware cable calculators";
-"cable.pro.feature.batteryCapacity" = "Configure usable battery capacity";
-"cable.pro.feature.usageBased" = "Usage based calculations";
-"cable.pro.button.unlock" = "Unlock Now";
-"cable.pro.button.freeTrial" = "Start Free Trial";
-"cable.pro.button.unlocked" = "Unlocked";
-"cable.pro.restore.button" = "Restore Purchases";
-"cable.pro.alert.success.title" = "Cable PRO Unlocked";
-"cable.pro.alert.success.body" = "Thanks for supporting Cable PRO!";
-"cable.pro.alert.pending.title" = "Purchase Pending";
-"cable.pro.alert.pending.body" = "Your purchase is awaiting approval.";
-"cable.pro.alert.restored.title" = "Purchases Restored";
-"cable.pro.alert.restored.body" = "Your purchases are available again.";
-"cable.pro.alert.error.title" = "Purchase Failed";
-"cable.pro.alert.error.generic" = "Something went wrong. Please try again.";
 "generic.ok" = "OK";
-"cable.pro.trial.badge" = "Includes a %@ free trial";
-"cable.pro.subscription.renews" = "Renews %@.";
-"cable.pro.subscription.trialThenRenews" = "Free trial, then renews %@.";
-"cable.pro.duration.day.singular" = "every day";
-"cable.pro.duration.day.plural" = "every %@ days";
-"cable.pro.duration.week.singular" = "every week";
-"cable.pro.duration.week.plural" = "every %@ weeks";
-"cable.pro.duration.month.singular" = "every month";
-"cable.pro.duration.month.plural" = "every %@ months";
-"cable.pro.duration.year.singular" = "every year";
-"cable.pro.duration.year.plural" = "every %@ years";
-"cable.pro.trial.duration.day.singular" = "%@-day";
-"cable.pro.trial.duration.day.plural" = "%@-day";
-"cable.pro.trial.duration.week.singular" = "%@-week";
-"cable.pro.trial.duration.week.plural" = "%@-week";
-"cable.pro.trial.duration.month.singular" = "%@-month";
-"cable.pro.trial.duration.month.plural" = "%@-month";
-"cable.pro.trial.duration.year.singular" = "%@-year";
-"cable.pro.trial.duration.year.plural" = "%@-year";
 
 // MARK: - PDF Overview Export
 "overview.pdf.loads.section" = "Loads";
@@ -388,3 +344,10 @@
 "overview.share.diagram" = "Wiring Diagram";
 "overview.share.pdf" = "Full Report (PDF)";
 "overview.share.diagram.error" = "Could not generate diagram. Check your internet connection.";
+
+"editor.system.voltage_drop.label" = "Voltage drop budget";
+"editor.system.voltage_drop.hint.critical" = "3 % — for critical circuits like navigation, bilge pumps and electronics.";
+"editor.system.voltage_drop.hint.standard" = "5 % — balanced default for mixed installations.";
+"editor.system.voltage_drop.hint.noncritical" = "10 % — for non-critical loads such as cabin lighting.";
+"settings.voltage_drop.label" = "Voltage drop budget";
+"settings.voltage_drop.footnote" = "Used by the calculator and for new systems. Existing systems keep their own budget.";

Cable/Loads/CableCalculator.swift

@@ -16,6 +16,7 @@ class CableCalculator: ObservableObject {
     @Published var loadName: String = String(localized: "default.load.name", comment: "Default placeholder name for a load")
     @Published var dutyCyclePercent: Double = 100.0
     @Published var dailyUsageHours: Double = 24.0
+    @Published var maxVoltageDropPercent: Double = ElectricalCalculations.defaultMaxVoltageDropPercent
     
     var calculatedPower: Double {
         voltage * current
@@ -38,7 +39,8 @@ class CableCalculator: ObservableObject {
             length: length,
             current: current,
             voltage: voltage,
-            unitSystem: unitSystem
+            unitSystem: unitSystem,
+            maxVoltageDropPercent: maxVoltageDropPercent
         )
     }
 
@@ -51,7 +53,8 @@ class CableCalculator: ObservableObject {
             length: length,
             current: current,
             voltage: voltage,
-            unitSystem: unitSystem
+            unitSystem: unitSystem,
+            maxVoltageDropPercent: maxVoltageDropPercent
         )
     }
 
@@ -60,7 +63,8 @@ class CableCalculator: ObservableObject {
             length: length,
             current: current,
             voltage: voltage,
-            unitSystem: unitSystem
+            unitSystem: unitSystem,
+            maxVoltageDropPercent: maxVoltageDropPercent
         )
     }
 
@@ -69,7 +73,8 @@ class CableCalculator: ObservableObject {
             length: length,
             current: current,
             voltage: voltage,
-            unitSystem: unitSystem
+            unitSystem: unitSystem,
+            maxVoltageDropPercent: maxVoltageDropPercent
         )
     }
     
@@ -92,6 +97,9 @@ class ElectricalSystem {
     var colorName: String = "blue"
     var targetRuntimeHours: Double?
     var targetChargeTimeHours: Double?
+    /// Share of system voltage that may be lost in a cable. Stored per system so a critical
+    /// 12 V circuit can be planned at 3 % while a cabin light stays at 10 %.
+    var maxVoltageDropPercent: Double = ElectricalCalculations.defaultMaxVoltageDropPercent
     
     init(
         name: String,
@@ -99,7 +107,8 @@ class ElectricalSystem {
         iconName: String = "building.2",
         colorName: String = "blue",
         targetRuntimeHours: Double? = nil,
-        targetChargeTimeHours: Double? = nil
+        targetChargeTimeHours: Double? = nil,
+        maxVoltageDropPercent: Double = ElectricalCalculations.defaultMaxVoltageDropPercent
     ) {
         self.name = name
         self.location = location
@@ -108,6 +117,7 @@ class ElectricalSystem {
         self.colorName = colorName
         self.targetRuntimeHours = targetRuntimeHours
         self.targetChargeTimeHours = targetChargeTimeHours
+        self.maxVoltageDropPercent = maxVoltageDropPercent
     }
 }
 

Cable/Loads/CalculatorView.swift

@@ -345,10 +345,14 @@ struct CalculatorView: View {
             .sheet(isPresented: $showingLoadEditor, content: loadEditorSheet)
             .sheet(item: $presentedAffiliateLink, content: billOfMaterialsSheet(info:))
             .onAppear {
+                calculator.maxVoltageDropPercent = unitSettings.voltageDropTargetPercent
                 if let savedLoad = savedLoad {
                     loadConfiguration(from: savedLoad)
                 }
             }
+            .onChange(of: unitSettings.voltageDropTargetPercent) { _, newValue in
+                calculator.maxVoltageDropPercent = newValue
+            }
             .onChange(of: completedItemIDs) { _, _ in
                 persistCompletedItems()
             }
@@ -701,7 +705,7 @@ struct CalculatorView: View {
                 Button(action: {}) {
                     Text(String(format: "%.1fV (%.1f%%)", calculator.voltageDrop(for: unitSettings.unitSystem), calculator.voltageDropPercentage(for: unitSettings.unitSystem)))
                         .fontWeight(.medium)
-                        .foregroundColor(calculator.voltageDropPercentage(for: unitSettings.unitSystem) > 5 ? .orange : .primary)
+                        .foregroundColor(calculator.voltageDropPercentage(for: unitSettings.unitSystem) > calculator.maxVoltageDropPercent ? .orange : .primary)
                 }
                 .buttonStyle(.plain)
                 

Cable/Loads/ElectricalCalculations.swift

@@ -8,7 +8,9 @@
 import Foundation
 
 struct ElectricalCalculations {
-    private static let maxVoltageDropFraction = 0.05
+    /// Default share of system voltage that may be lost in the cable. ABYC E-11 works with
+    /// 3 % for critical circuits and 10 % for non-critical ones; 5 % is the middle ground.
+    static let defaultMaxVoltageDropPercent = 5.0
     private static let copperResistivity = 0.017 // Ω⋅mm²/m
     private static let feetToMeters = 0.3048
 
@@ -29,27 +31,87 @@ struct ElectricalCalculations {
         300, 350, 400, 450, 500, 600, 700, 800,
     ]
 
+    /// Ampacity of the AWG ladder in amps. Source: ABYC E-11 Table 6A, 105 °C insulation
+    /// rating, outside engine spaces, single conductors not bundled. Index-aligned with
+    /// `standardAWG`. AWG 20 is not covered by the table, so it is never selected on
+    /// ampacity grounds.
+    private static let awgAmpacity: [Double] = [
+        0, 20, 25, 35, 45, 60, 80, 120, 160, 210, 245, 285, 330, 385, 445,
+    ]
+
+    /// Ampacity of the metric ladder in amps. Source: ISO 13297 Table A1, 105 °C insulation
+    /// rating, bundles up to three conductors. The standard tabulates 0.75–150 mm²; larger
+    /// cross-sections inherit the 150 mm² value as a conservative lower bound. Index-aligned
+    /// with `standardMetricCrossSections`.
+    private static let metricAmpacity: [Double] = [
+        16, 20, 25, 35, 45, 60, 90, 130, 170, 210, 270, 330, 390, 450, 475,
+        475, 475, 475, 475, 475, 475,
+    ]
+
+    /// Current-carrying capacity of a cable in amps. `crossSection` is mm² for `.metric`
+    /// and an AWG value (see `standardAWG`) for `.imperial`. Cross-sections between two
+    /// standard sizes are rated with the smaller neighbour.
+    static func ampacity(forCrossSection crossSection: Double, unitSystem: UnitSystem) -> Double {
+        if unitSystem == .imperial {
+            guard let index = standardAWG.firstIndex(of: Int(crossSection)) else { return 0 }
+            return awgAmpacity[index]
+        }
+        var rating = 0.0
+        for (index, area) in standardMetricCrossSections.enumerated() where area <= crossSection {
+            rating = metricAmpacity[index]
+        }
+        return rating
+    }
+
+    /// Nearest AWG size for a stored metric cross-section. Used to display mm² values in
+    /// AWG; picks the closest ladder entry, not the next larger one.
+    static func nearestAWG(forCrossSectionMM2 crossSection: Double) -> Double {
+        guard crossSection > 0 else { return 0 }
+        var bestAWG = standardAWG.first ?? 20
+        var bestDelta = Double.greatestFiniteMagnitude
+        for (index, area) in awgCrossSections.enumerated() {
+            let delta = abs(area - crossSection)
+            if delta < bestDelta {
+                bestDelta = delta
+                bestAWG = standardAWG[index]
+            }
+        }
+        return Double(bestAWG)
+    }
+
     /// Length must always be in meters. unitSystem controls the output format (mm² vs AWG).
+    ///
+    /// The recommendation satisfies two independent criteria, whichever one demands more
+    /// copper: the voltage-drop budget, and an ampacity at least as high as the fuse that
+    /// protects the circuit. The latter follows ABYC E-11, which requires the rating of the
+    /// overcurrent protection device to not exceed the ampacity of the conductor it protects.
     static func recommendedCrossSection(
         length: Double,
         current: Double,
         voltage: Double,
-        unitSystem: UnitSystem
+        unitSystem: UnitSystem,
+        maxVoltageDropPercent: Double = defaultMaxVoltageDropPercent
     ) -> Double {
         let lengthInMeters = length
-        let maxVoltageDrop = voltage * maxVoltageDropFraction
+        let maxVoltageDrop = voltage * (maxVoltageDropPercent / 100)
         let minimumCrossSection = guardAgainstZero(maxVoltageDrop) {
             (2 * current * lengthInMeters * copperResistivity) / maxVoltageDrop
         }
+        let requiredAmpacity = recommendedFuse(forCurrent: current)
 
         if unitSystem == .imperial {
-            for (index, crossSection) in awgCrossSections.enumerated() where crossSection >= minimumCrossSection {
+            for (index, crossSection) in awgCrossSections.enumerated()
+            where crossSection >= minimumCrossSection && awgAmpacity[index] >= requiredAmpacity {
                 return Double(standardAWG[index])
             }
             return Double(standardAWG.last ?? 0)
         } else {
-            return standardMetricCrossSections.first { $0 >= max(standardMetricCrossSections.first ?? 0.75, minimumCrossSection) }
-                ?? standardMetricCrossSections.last ?? 0.75
+            let minimumArea = max(standardMetricCrossSections.first ?? 0.75, minimumCrossSection)
+            for (index, crossSection) in standardMetricCrossSections.enumerated()
+            where crossSection >= minimumArea && metricAmpacity[index] >= requiredAmpacity {
+                return crossSection
+            }
+            return standardMetricCrossSections.last ?? 0.75
         }
     }
 
@@ -58,13 +120,15 @@ struct ElectricalCalculations {
         current: Double,
         voltage: Double,
         unitSystem: UnitSystem,
-        crossSection: Double? = nil
+        crossSection: Double? = nil,
+        maxVoltageDropPercent: Double = defaultMaxVoltageDropPercent
     ) -> Double {
         let selectedCrossSection = crossSection ?? recommendedCrossSection(
             length: length,
             current: current,
             voltage: voltage,
-            unitSystem: unitSystem
+            unitSystem: unitSystem,
+            maxVoltageDropPercent: maxVoltageDropPercent
         )
 
         let lengthInMeters = length
@@ -84,7 +148,8 @@ struct ElectricalCalculations {
         current: Double,
         voltage: Double,
         unitSystem: UnitSystem,
-        crossSection: Double? = nil
+        crossSection: Double? = nil,
+        maxVoltageDropPercent: Double = defaultMaxVoltageDropPercent
     ) -> Double {
         guard voltage != 0 else { return 0 }
         let drop = voltageDrop(
@@ -92,7 +157,8 @@ struct ElectricalCalculations {
             current: current,
             voltage: voltage,
             unitSystem: unitSystem,
-            crossSection: crossSection
+            crossSection: crossSection,
+            maxVoltageDropPercent: maxVoltageDropPercent
         )
         return (drop / voltage) * 100
     }
@@ -102,14 +168,16 @@ struct ElectricalCalculations {
         current: Double,
         voltage: Double,
         unitSystem: UnitSystem,
-        crossSection: Double? = nil
+        crossSection: Double? = nil,
+        maxVoltageDropPercent: Double = defaultMaxVoltageDropPercent
     ) -> Double {
         let drop = voltageDrop(
             length: length,
             current: current,
             voltage: voltage,
             unitSystem: unitSystem,
-            crossSection: crossSection
+            crossSection: crossSection,
+            maxVoltageDropPercent: maxVoltageDropPercent
         )
         return current * drop
     }

Cable/Loads/LoadCableSync.swift

@@ -0,0 +1,32 @@
+import Foundation
+
+/// The cross-section of a load is derived, never entered by the user: it follows from length,
+/// current, voltage and the system's voltage-drop budget. Whenever one of those inputs changes,
+/// the stored value has to follow — otherwise the app displays a size it no longer stands behind
+/// and would have to ask the user to fix something only the app can compute.
+enum LoadCableSync {
+    /// Sets every load's cross-section to the size the app would recommend right now.
+    /// Returns how many loads changed, so callers can log or react without diffing themselves.
+    @discardableResult
+    static func synchronize(loads: [SavedLoad], maxVoltageDropPercent: Double) -> Int {
+        var changed = 0
+        for load in loads where load.length > 0 && load.current > 0 {
+            let recommended = ElectricalCalculations.recommendedCrossSection(
+                length: load.length,
+                current: load.current,
+                voltage: load.voltage,
+                unitSystem: .metric,
+                maxVoltageDropPercent: maxVoltageDropPercent
+            )
+            guard abs(load.crossSection - recommended) > 0.0001 else { continue }
+            load.crossSection = recommended
+            changed += 1
+        }
+        return changed
+    }
+
+    @discardableResult
+    static func synchronize(loads: [SavedLoad], for system: ElectricalSystem) -> Int {
+        synchronize(loads: loads, maxVoltageDropPercent: system.maxVoltageDropPercent)
+    }
+}

Cable/Loads/LoadConfigurationStatus.swift

@@ -1,8 +1,21 @@
 import SwiftUI
 
+/// The only load problem the app cannot solve on its own: missing length or current.
+/// Cross-sections are derived and kept in sync by `LoadCableSync`, so an undersized cable
+/// can no longer occur — there is nothing to warn about that the user would have to fix.
 enum LoadConfigurationStatus: Identifiable, Equatable {
     case missingDetails(count: Int)
 
+    static func evaluate(loads: [SavedLoad]) -> LoadConfigurationStatus? {
+        guard !loads.isEmpty else { return nil }
+
+        let incomplete = loads.filter { load in
+            load.length <= 0 || load.current <= 0 || load.crossSection <= 0
+        }
+        guard !incomplete.isEmpty else { return nil }
+        return .missingDetails(count: incomplete.count)
+    }
+
     var id: String {
         switch self {
         case .missingDetails(let count):
@@ -43,7 +56,7 @@ enum LoadConfigurationStatus: Identifiable, Equatable {
             )
             let format = String(
                 localized: "loads.overview.status.missing_details.message",
-                defaultValue: "Enter cable length and wire size for %d %@ to see accurate recommendations."
+                defaultValue: "Enter cable length and current draw for %d %@ so Cable can size the wiring."
             )
             let loadWord = count == 1
                 ? String(
@@ -54,8 +67,7 @@ enum LoadConfigurationStatus: Identifiable, Equatable {
                     localized: "loads.overview.status.missing_details.plural",
                     defaultValue: "loads"
                 )
-            let message = String(format: format, count, loadWord)
-            return LoadStatusDetail(title: title, message: message)
+            return LoadStatusDetail(title: title, message: String(format: format, count, loadWord))
         }
     }
 }

Cable/Loads/LoadsView.swift

@@ -145,6 +145,7 @@ struct LoadsView: View {
                             .foregroundColor(.primary)
                     }
                 }
+                .accessibilityIdentifier("system-title-button")
             }
             
             ToolbarItem(placement: .navigationBarTrailing) {
@@ -302,6 +303,18 @@ struct LoadsView: View {
                 colorName: Binding(
                     get: { system.colorName },
                     set: { system.colorName = $0 }
+                ),
+                maxVoltageDropPercent: Binding(
+                    get: { system.maxVoltageDropPercent },
+                    set: { newValue in
+                        system.maxVoltageDropPercent = newValue
+                        // The budget is an input to every cable size, so the stored sizes follow.
+                        let resized = LoadCableSync.synchronize(loads: savedLoads, for: system)
+                        AnalyticsTracker.log("Voltage Drop Budget Changed", properties: [
+                            "percent": newValue,
+                            "resized_loads": resized,
+                        ])
+                    }
                 )
             )
         }
@@ -318,6 +331,8 @@ struct LoadsView: View {
             )
         }
         .onAppear {
+            LoadCableSync.synchronize(loads: savedLoads, for: system)
+
             if presentSystemEditorOnAppear && !hasPresentedSystemEditorOnAppear {
                 hasPresentedSystemEditorOnAppear = true
                 DispatchQueue.main.async {
@@ -761,14 +776,7 @@ struct LoadsView: View {
     }
 
     private var loadStatus: LoadConfigurationStatus? {
-        guard !savedLoads.isEmpty else { return nil }
-        let incompleteLoads = savedLoads.filter { load in
-            load.length <= 0 || load.crossSection <= 0
-        }
-        if !incompleteLoads.isEmpty {
-            return .missingDetails(count: incompleteLoads.count)
-        }
-        return nil
+        LoadConfigurationStatus.evaluate(loads: savedLoads)
     }
 
     private func summaryMetric(icon: String, label: String, value: String, tint: Color) -> some View {
@@ -1102,13 +1110,7 @@ struct LoadsView: View {
     }
     
     private func awgFromCrossSection(_ crossSectionMM2: Double) -> Double {
-        let awgSizes: [(Int, Double)] = [(20, 0.519), (18, 0.823), (16, 1.31), (14, 2.08), (12, 3.31),
-                       (10, 5.26), (8, 8.37), (6, 13.3), (4, 21.2), (2, 33.6),
-                       (1, 42.4), (-1, 53.5), (-2, 67.4), (-3, 85.0), (-4, 107.0)]
-
-        // Find the closest AWG size
-        let closest = awgSizes.min { abs($0.1 - crossSectionMM2) < abs($1.1 - crossSectionMM2) }
-        return Double(closest?.0 ?? 20)
+        ElectricalCalculations.nearestAWG(forCrossSectionMM2: crossSectionMM2)
     }
 
     private func recommendedFuse(for load: SavedLoad) -> String {
@@ -1218,16 +1220,20 @@ struct LoadsView: View {
                 dutyCyclePercent: load.dutyCyclePercent,
                 dailyUsageHours: load.dailyUsageHours,
                 recommendedCrossSection: ElectricalCalculations.recommendedCrossSection(
-                    length: load.length, current: load.current, voltage: load.voltage, unitSystem: currentUnitSystem
+                    length: load.length, current: load.current, voltage: load.voltage,
+                    unitSystem: currentUnitSystem, maxVoltageDropPercent: system.maxVoltageDropPercent
                 ),
                 voltageDrop: ElectricalCalculations.voltageDrop(
-                    length: load.length, current: load.current, voltage: load.voltage, unitSystem: currentUnitSystem
+                    length: load.length, current: load.current, voltage: load.voltage,
+                    unitSystem: currentUnitSystem, maxVoltageDropPercent: system.maxVoltageDropPercent
                 ),
                 voltageDropPercent: ElectricalCalculations.voltageDropPercentage(
-                    length: load.length, current: load.current, voltage: load.voltage, unitSystem: currentUnitSystem
+                    length: load.length, current: load.current, voltage: load.voltage,
+                    unitSystem: currentUnitSystem, maxVoltageDropPercent: system.maxVoltageDropPercent
                 ),
                 powerLoss: ElectricalCalculations.powerLoss(
-                    length: load.length, current: load.current, voltage: load.voltage, unitSystem: currentUnitSystem
+                    length: load.length, current: load.current, voltage: load.voltage,
+                    unitSystem: currentUnitSystem, maxVoltageDropPercent: system.maxVoltageDropPercent
                 ),
                 recommendedFuse: ElectricalCalculations.recommendedFuse(forCurrent: load.current),
                 iconUrl: load.remoteIconURLString

Cable/Overview/SystemOverviewView.swift

@@ -4,6 +4,7 @@ import SwiftData
 struct SystemOverviewView: View {
     @Environment(\.dismiss) private var dismiss
     @Environment(\.modelContext) private var modelContext
+
     @State private var activeStatus: LoadConfigurationStatus?
     @State private var suppressLoadNavigation = false
     @State private var showingRuntimeGoalEditor = false
@@ -390,7 +391,6 @@ struct SystemOverviewView: View {
                         .fill(Color(.tertiarySystemBackground))
                 )
             }
-            .buttonStyle(.plain)
             .alert(item: $activeStatus) { status in
                 let detail = status.detailInfo()
                 return Alert(
@@ -588,14 +588,7 @@ struct SystemOverviewView: View {
     }
 
     private var loadStatus: LoadConfigurationStatus? {
-        guard !loads.isEmpty else { return nil }
-        let incomplete = loads.filter { load in
-            load.length <= 0 || load.crossSection <= 0
-        }
-        if !incomplete.isEmpty {
-            return .missingDetails(count: incomplete.count)
-        }
-        return nil
+        LoadConfigurationStatus.evaluate(loads: loads)
     }
 
     private var totalCurrent: Double {

Cable/SettingsView.swift

@@ -24,6 +24,28 @@ struct SettingsView: View {
                     }
                     .pickerStyle(.segmented)
                 }
+                Section {
+                    Picker(
+                        String(
+                            localized: "settings.voltage_drop.label",
+                            defaultValue: "Voltage drop budget"
+                        ),
+                        selection: $unitSettings.voltageDropTargetPercent
+                    ) {
+                        ForEach([3.0, 5.0, 10.0], id: \.self) { target in
+                            Text(String(format: "%.0f %%", target)).tag(target)
+                        }
+                    }
+                    .pickerStyle(.segmented)
+                    Text(
+                        String(
+                            localized: "settings.voltage_drop.footnote",
+                            defaultValue: "Used by the calculator and for new systems. Existing systems keep their own budget."
+                        )
+                    )
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+                }
                 Section {
                     VStack(alignment: .leading, spacing: 12) {
                         HStack(spacing: 8) {

Cable/Systems/SystemBillOfMaterialsView.swift

@@ -852,19 +852,7 @@ struct SystemBillOfMaterialsView: View {
     }
 
     private func awgFromCrossSection(_ crossSectionMM2: Double) -> Double {
-        let mapping: [(awg: Double, area: Double)] = [
-            (20, 0.519), (18, 0.823), (16, 1.31), (14, 2.08), (12, 3.31), (10, 5.26),
-            (8, 8.37), (6, 13.3), (4, 21.2), (2, 33.6), (1, 42.4), (-1, 53.5),
-            (-2, 67.4), (-3, 85.0), (-4, 107.0)
-        ]
-
-        guard crossSectionMM2 > 0 else { return 0 }
-
-        let closest = mapping.min { lhs, rhs in
-            abs(lhs.area - crossSectionMM2) < abs(rhs.area - crossSectionMM2)
-        }
-
-        return closest?.awg ?? 0
+        ElectricalCalculations.nearestAWG(forCrossSectionMM2: crossSectionMM2)
     }
 
     private var footerMessage: String {

Cable/Systems/SystemComponentsPersistence.swift

@@ -20,13 +20,22 @@ struct SystemComponentsPersistence {
             batteries: existingBatteries,
             chargers: existingChargers
         )
+        let defaultLength = 10.0
+        let defaultVoltage = 12.0
+        let defaultCurrent = 5.0
         let newLoad = SavedLoad(
             name: loadName,
-            voltage: 12.0,
-            current: 5.0,
-            power: 60.0,
-            length: 10.0,
-            crossSection: 1.0,
+            voltage: defaultVoltage,
+            current: defaultCurrent,
+            power: defaultVoltage * defaultCurrent,
+            length: defaultLength,
+            crossSection: ElectricalCalculations.recommendedCrossSection(
+                length: defaultLength,
+                current: defaultCurrent,
+                voltage: defaultVoltage,
+                unitSystem: .metric,
+                maxVoltageDropPercent: system.maxVoltageDropPercent
+            ),
             iconName: "lightbulb",
             colorName: "blue",
             isWattMode: false,
@@ -69,13 +78,20 @@ struct SystemComponentsPersistence {
         let dutyCyclePercent = item.normalizedDutyCyclePercent ?? 100
         let dailyUsageHours = item.defaultDailyUsageHours ?? 1
 
+        let length = 10.0
         let newLoad = SavedLoad(
             name: loadName,
             voltage: voltage,
             current: current,
             power: power,
-            length: 10.0,
-            crossSection: 1.0,
+            length: length,
+            crossSection: ElectricalCalculations.recommendedCrossSection(
+                length: length,
+                current: current,
+                voltage: voltage,
+                unitSystem: .metric,
+                maxVoltageDropPercent: system.maxVoltageDropPercent
+            ),
             iconName: "lightbulb",
             colorName: "blue",
             isWattMode: item.watt != nil,

Cable/Systems/SystemEditorView.swift

@@ -12,6 +12,7 @@ struct SystemEditorView: View {
     @Binding var location: String
     @Binding var iconName: String
     @Binding var colorName: String
+    @Binding var maxVoltageDropPercent: Double
     
     @State private var tempLocation: String
     
@@ -23,11 +24,22 @@ struct SystemEditorView: View {
         "engine.combustion", "fuelpump", "drop", "flame", "snowflake", "thermometer"
     ]
     
-    init(systemName: Binding<String>, location: Binding<String>, iconName: Binding<String>, colorName: Binding<String>) {
+    /// Targets offered as presets: ABYC E-11 uses 3 % for critical circuits and 10 % for
+    /// non-critical ones, 5 % is the default middle ground.
+    private let voltageDropTargets: [Double] = [3, 5, 10]
+
+    init(
+        systemName: Binding<String>,
+        location: Binding<String>,
+        iconName: Binding<String>,
+        colorName: Binding<String>,
+        maxVoltageDropPercent: Binding<Double>
+    ) {
         self._systemName = systemName
         self._location = location
         self._iconName = iconName
         self._colorName = colorName
+        self._maxVoltageDropPercent = maxVoltageDropPercent
         self._tempLocation = State(initialValue: location.wrappedValue)
     }
     
@@ -46,11 +58,41 @@ struct SystemEditorView: View {
             colorName: $colorName,
             additionalFields: {
                 AnyView(
+                    VStack(alignment: .leading, spacing: 12) {
                         TextField(locationPlaceholder, text: $tempLocation)
                             .autocapitalization(.words)
                             .onChange(of: tempLocation) { _, newValue in
                                 location = newValue
                             }
+
+                        VStack(alignment: .leading, spacing: 6) {
+                            Text(
+                                String(
+                                    localized: "editor.system.voltage_drop.label",
+                                    defaultValue: "Voltage drop budget"
+                                )
+                            )
+                            .font(.subheadline.weight(.semibold))
+
+                            Picker(
+                                String(
+                                    localized: "editor.system.voltage_drop.label",
+                                    defaultValue: "Voltage drop budget"
+                                ),
+                                selection: $maxVoltageDropPercent
+                            ) {
+                                ForEach(voltageDropTargets, id: \.self) { target in
+                                    Text(String(format: "%.0f %%", target)).tag(target)
+                                }
+                            }
+                            .pickerStyle(.segmented)
+                            .accessibilityIdentifier("system-voltage-drop-picker")
+
+                            Text(voltageDropHint)
+                                .font(.caption)
+                                .foregroundStyle(.secondary)
+                        }
+                    }
                 )
             }
         )
@@ -58,6 +100,26 @@ struct SystemEditorView: View {
             tempLocation = location
         }
     }
+
+    private var voltageDropHint: String {
+        switch maxVoltageDropPercent {
+        case ..<4:
+            return String(
+                localized: "editor.system.voltage_drop.hint.critical",
+                defaultValue: "3 % — for critical circuits like navigation, bilge pumps and electronics."
+            )
+        case ..<6:
+            return String(
+                localized: "editor.system.voltage_drop.hint.standard",
+                defaultValue: "5 % — balanced default for mixed installations."
+            )
+        default:
+            return String(
+                localized: "editor.system.voltage_drop.hint.noncritical",
+                defaultValue: "10 % — for non-critical loads such as cabin lighting."
+            )
+        }
+    }
 }
 
 #Preview {
@@ -65,6 +127,13 @@ struct SystemEditorView: View {
     @Previewable @State var location = "Main Building"
     @Previewable @State var icon = "building.2"
     @Previewable @State var color = "blue"
+    @Previewable @State var dropTarget = 5.0
 
-    return SystemEditorView(systemName: $name, location: $location, iconName: $icon, colorName: $color)
+    return SystemEditorView(
+        systemName: $name,
+        location: $location,
+        iconName: $icon,
+        colorName: $color,
+        maxVoltageDropPercent: $dropTarget
+    )
 }

Cable/Systems/SystemsView.swift

@@ -324,7 +324,8 @@ struct SystemsView: View {
             name: systemName,
             location: "",
             iconName: resolvedIconName,
-            colorName: resolvedColorName
+            colorName: resolvedColorName,
+            maxVoltageDropPercent: unitSettings.voltageDropTargetPercent
         )
         modelContext.insert(newSystem)
         return newSystem

Cable/UnitSystem.swift

@@ -58,6 +58,13 @@ class UnitSystemSettings: ObservableObject {
             AnalyticsTracker.log("Unit System Changed", properties: ["system": unitSystem.rawValue])
         }
     }
+    /// Applies to the standalone calculator and seeds newly created systems.
+    @Published var voltageDropTargetPercent: Double {
+        didSet {
+            UserDefaults.standard.set(voltageDropTargetPercent, forKey: "voltageDropTargetPercent")
+            AnalyticsTracker.log("Voltage Drop Target Changed", properties: ["percent": voltageDropTargetPercent])
+        }
+    }
 
     init() {
         if let saved = UserDefaults.standard.string(forKey: "unitSystem"),
@@ -66,5 +73,9 @@ class UnitSystemSettings: ObservableObject {
         } else {
             self.unitSystem = Locale.current.measurementSystem == .us ? .imperial : .metric
         }
+        let savedTarget = UserDefaults.standard.double(forKey: "voltageDropTargetPercent")
+        self.voltageDropTargetPercent = savedTarget > 0
+            ? savedTarget
+            : ElectricalCalculations.defaultMaxVoltageDropPercent
     }
 }

Cable/de.lproj/Localizable.strings

@@ -177,10 +177,6 @@
 "bom.quantity.terminal.badge" = "%1$d× · %2$@";
 "bom.quantity.cable.badge" = "%1$.1f %2$@ · %3$@";
 "bom.quantity.single.badge" = "1× • %@";
-"cable.pro.privacy.label" = "Datenschutz";
-"cable.pro.privacy.url" = "https://voltplan.app/de/datenschutz";
-"cable.pro.terms.label" = "Nutzungsbedingungen";
-"cable.pro.terms.url" = "https://voltplan.app/de/agb";
 "calculator.advanced.duty_cycle.helper" = "Prozentsatz der aktiven Zeit, in der die Last tatsächlich Leistung aufnimmt.";
 "calculator.advanced.duty_cycle.title" = "Einschaltdauer";
 "calculator.advanced.section.title" = "Erweitert";
@@ -259,7 +255,7 @@
 "loads.overview.metric.current" = "Strom";
 "loads.overview.metric.power" = "Leistung";
 "loads.overview.status.missing_details.banner" = "Konfiguration deiner Verbraucher abschließen";
-"loads.overview.status.missing_details.message" = "Gib Kabellänge und Leitungsquerschnitt für %d %@ ein, um genaue Empfehlungen zu erhalten.";
+"loads.overview.status.missing_details.message" = "Gib Kabellänge und Stromaufnahme für %d %@ ein, damit Cable die Leitung dimensionieren kann.";
 "loads.overview.status.missing_details.plural" = "Verbraucher";
 "loads.overview.status.missing_details.singular" = "Verbraucher";
 "loads.overview.status.missing_details.title" = "Fehlende Verbraucherdetails";
@@ -349,47 +345,7 @@
 "settings.pro.manage.url" = "https://apps.apple.com/account/subscriptions";
 "settings.pro.day.one" = "%@ Tag";
 "settings.pro.day.other" = "%@ Tage";
-"cable.pro.terms.label" = "AGB";
-"cable.pro.privacy.label" = "Datenschutz";
-"cable.pro.terms.url" = "https://voltplan.app/terms";
-"cable.pro.privacy.url" = "https://voltplan.app/privacy";
-"cable.pro.paywall.title" = "Cable PRO";
-"cable.pro.paywall.subtitle" = "Cable PRO bietet mehr Konfigurationsoptionen für Verbraucher, Batterien und Ladegeräte.";
-"cable.pro.feature.dutyCycle" = "Kabelberechnungen mit Einschaltdauer";
-"cable.pro.feature.batteryCapacity" = "Verfügbare Batteriekapazität konfigurieren";
-"cable.pro.feature.usageBased" = "Nutzungsbasierte Berechnungen";
-"cable.pro.button.unlock" = "Jetzt freischalten";
-"cable.pro.button.freeTrial" = "Kostenlose Testphase starten";
-"cable.pro.button.unlocked" = "Bereits aktiviert";
-"cable.pro.restore.button" = "Käufe wiederherstellen";
-"cable.pro.alert.success.title" = "Cable PRO aktiviert";
-"cable.pro.alert.success.body" = "Danke für deine Unterstützung!";
-"cable.pro.alert.pending.title" = "Kauf ausstehend";
-"cable.pro.alert.pending.body" = "Dein Kauf wartet auf Bestätigung.";
-"cable.pro.alert.restored.title" = "Käufe wiederhergestellt";
-"cable.pro.alert.restored.body" = "Deine bisherigen Käufe sind wieder verfügbar.";
-"cable.pro.alert.error.title" = "Kauf fehlgeschlagen";
-"cable.pro.alert.error.generic" = "Etwas ist schiefgelaufen. Bitte versuche es erneut.";
 "generic.ok" = "OK";
-"cable.pro.trial.badge" = "Enthält eine %@ Testphase";
-"cable.pro.subscription.renews" = "Verlängert sich %@.";
-"cable.pro.subscription.trialThenRenews" = "Testphase, danach Verlängerung %@.";
-"cable.pro.duration.day.singular" = "jeden Tag";
-"cable.pro.duration.day.plural" = "alle %@ Tage";
-"cable.pro.duration.week.singular" = "jede Woche";
-"cable.pro.duration.week.plural" = "alle %@ Wochen";
-"cable.pro.duration.month.singular" = "monatlich";
-"cable.pro.duration.month.plural" = "alle %@ Monate";
-"cable.pro.duration.year.singular" = "jährlich";
-"cable.pro.duration.year.plural" = "alle %@ Jahre";
-"cable.pro.trial.duration.day.singular" = "%@-tägige";
-"cable.pro.trial.duration.day.plural" = "%@-tägige";
-"cable.pro.trial.duration.week.singular" = "%@-wöchige";
-"cable.pro.trial.duration.week.plural" = "%@-wöchige";
-"cable.pro.trial.duration.month.singular" = "%@-monatige";
-"cable.pro.trial.duration.month.plural" = "%@-monatige";
-"cable.pro.trial.duration.year.singular" = "%@-jährige";
-"cable.pro.trial.duration.year.plural" = "%@-jährige";
 "• Always consult qualified electricians for actual installations" = "• Ziehe für tatsächliche Installationen stets qualifizierte Elektriker hinzu";
 "• Electrical work should only be performed by licensed professionals" = "• Elektroarbeiten sollten nur von zertifizierten Fachkräften ausgeführt werden";
 "• Follow all local electrical codes and regulations" = "• Beachte alle örtlichen Vorschriften und Normen";
@@ -453,3 +409,10 @@
 "overview.share.diagram" = "Schaltplan";
 "overview.share.pdf" = "Vollständiger Bericht (PDF)";
 "overview.share.diagram.error" = "Schaltplan konnte nicht erstellt werden. Überprüfe deine Internetverbindung.";
+
+"editor.system.voltage_drop.label" = "Spannungsfall-Budget";
+"editor.system.voltage_drop.hint.critical" = "3 % — für kritische Stromkreise wie Navigation, Bilgepumpe und Elektronik.";
+"editor.system.voltage_drop.hint.standard" = "5 % — ausgewogener Standard für gemischte Installationen.";
+"editor.system.voltage_drop.hint.noncritical" = "10 % — für unkritische Verbraucher wie Innenbeleuchtung.";
+"settings.voltage_drop.label" = "Spannungsfall-Budget";
+"settings.voltage_drop.footnote" = "Gilt für den Rechner und neue Systeme. Bestehende Systeme behalten ihr eigenes Budget.";

Cable/es.lproj/Localizable.strings

@@ -196,7 +196,7 @@
 "loads.onboarding.title" = "Añade tu primer consumidor";
 "loads.onboarding.subtitle" = "Completa tu sistema con consumidores y deja que **Cable by VoltPlan** calcule cables y fusibles por ti.";
 "loads.overview.status.missing_details.title" = "Faltan detalles de la carga";
-"loads.overview.status.missing_details.message" = "Introduce la longitud del cable y el calibre del conductor para %d %@ para obtener recomendaciones precisas.";
+"loads.overview.status.missing_details.message" = "Introduce la longitud del cable y la corriente de %d %@ para que Cable dimensione el cableado.";
 "loads.overview.status.missing_details.singular" = "carga";
 "loads.overview.status.missing_details.plural" = "cargas";
 "loads.overview.status.missing_details.banner" = "Completa la configuración de tus cargas";
@@ -351,11 +351,6 @@
 "chargers.title" = "Cargadores para %@";
 "chargers.subtitle" = "Los componentes de carga estarán disponibles pronto.";
 
-"cable.pro.paywall.title" = "Cable PRO";
-"cable.pro.paywall.subtitle" = "Cable PRO permite más opciones de configuración para cargas, baterías y cargadores.";
-"cable.pro.feature.dutyCycle" = "Calculadoras de cables conscientes del ciclo de trabajo";
-"cable.pro.feature.batteryCapacity" = "Configura la capacidad utilizable de la batería";
-"cable.pro.feature.usageBased" = "Cálculos basados en el uso";
 "generic.ok" = "Aceptar";
 
 // MARK: - PDF Overview Export
@@ -415,3 +410,10 @@
 "overview.share.diagram" = "Diagrama de cableado";
 "overview.share.pdf" = "Informe completo (PDF)";
 "overview.share.diagram.error" = "No se pudo generar el diagrama. Comprueba tu conexión a Internet.";
+
+"editor.system.voltage_drop.label" = "Caída de tensión admisible";
+"editor.system.voltage_drop.hint.critical" = "3 % — para circuitos críticos como navegación, bombas de sentina y electrónica.";
+"editor.system.voltage_drop.hint.standard" = "5 % — valor equilibrado para instalaciones mixtas.";
+"editor.system.voltage_drop.hint.noncritical" = "10 % — para consumos no críticos como la iluminación interior.";
+"settings.voltage_drop.label" = "Caída de tensión admisible";
+"settings.voltage_drop.footnote" = "Se aplica a la calculadora y a los sistemas nuevos. Los sistemas existentes conservan su valor.";

Cable/fr.lproj/Localizable.strings

@@ -196,7 +196,7 @@
 "loads.onboarding.title" = "Ajoutez votre premier consommateur";
 "loads.onboarding.subtitle" = "Complétez votre système avec des équipements et laissez **Cable by VoltPlan** proposer les câbles et fusibles adaptés.";
 "loads.overview.status.missing_details.title" = "Détails de charge manquants";
-"loads.overview.status.missing_details.message" = "Saisissez la longueur de câble et la section du conducteur pour %d %@ afin d'obtenir des recommandations précises.";
+"loads.overview.status.missing_details.message" = "Indiquez la longueur de câble et le courant de %d %@ pour que Cable dimensionne le câblage.";
 "loads.overview.status.missing_details.singular" = "charge";
 "loads.overview.status.missing_details.plural" = "charges";
 "loads.overview.status.missing_details.banner" = "Terminez la configuration de vos charges";
@@ -351,11 +351,6 @@
 "chargers.title" = "Chargeurs pour %@";
 "chargers.subtitle" = "Les chargeurs seront bientôt disponibles ici.";
 
-"cable.pro.paywall.title" = "Cable PRO";
-"cable.pro.paywall.subtitle" = "Cable PRO offre davantage d'options de configuration pour les charges, les batteries et les chargeurs.";
-"cable.pro.feature.dutyCycle" = "Calculs de câbles tenant compte du cycle d'utilisation";
-"cable.pro.feature.batteryCapacity" = "Configurez la capacité utilisable de la batterie";
-"cable.pro.feature.usageBased" = "Calculs basés sur l’utilisation";
 "generic.ok" = "OK";
 
 // MARK: - PDF Overview Export
@@ -415,3 +410,10 @@
 "overview.share.diagram" = "Schéma de câblage";
 "overview.share.pdf" = "Rapport complet (PDF)";
 "overview.share.diagram.error" = "Impossible de générer le schéma. Vérifiez votre connexion Internet.";
+
+"editor.system.voltage_drop.label" = "Chute de tension admissible";
+"editor.system.voltage_drop.hint.critical" = "3 % — pour les circuits critiques : navigation, pompe de cale, électronique.";
+"editor.system.voltage_drop.hint.standard" = "5 % — valeur équilibrée pour les installations mixtes.";
+"editor.system.voltage_drop.hint.noncritical" = "10 % — pour les charges non critiques comme l’éclairage intérieur.";
+"settings.voltage_drop.label" = "Chute de tension admissible";
+"settings.voltage_drop.footnote" = "S’applique au calculateur et aux nouvelles installations. Les installations existantes gardent leur valeur.";

Cable/nl.lproj/Localizable.strings

@@ -196,7 +196,7 @@
 "loads.onboarding.title" = "Voeg je eerste verbruiker toe";
 "loads.onboarding.subtitle" = "Bouw je systeem uit met verbruikers en laat **Cable by VoltPlan** de kabel- en zekeringadviezen verzorgen.";
 "loads.overview.status.missing_details.title" = "Ontbrekende lastdetails";
-"loads.overview.status.missing_details.message" = "Voer kabellengte en kabeldoorsnede in voor %d %@ om nauwkeurige aanbevelingen te krijgen.";
+"loads.overview.status.missing_details.message" = "Vul kabellengte en stroom van %d %@ in zodat Cable de kabel kan dimensioneren.";
 "loads.overview.status.missing_details.singular" = "last";
 "loads.overview.status.missing_details.plural" = "lasten";
 "loads.overview.status.missing_details.banner" = "Rond de configuratie van je lasten af";
@@ -351,11 +351,6 @@
 "chargers.title" = "Laders voor %@";
 "chargers.subtitle" = "Ladercomponenten zijn binnenkort beschikbaar.";
 
-"cable.pro.paywall.title" = "Cable PRO";
-"cable.pro.paywall.subtitle" = "Cable PRO biedt meer configuratie-opties voor verbruikers, batterijen en laders.";
-"cable.pro.feature.dutyCycle" = "Kabelberekeningen die rekening houden met de inschakelduur";
-"cable.pro.feature.batteryCapacity" = "Configureer bruikbare batterijcapaciteit";
-"cable.pro.feature.usageBased" = "Gebruiksgestuurde berekeningen";
 "generic.ok" = "OK";
 
 // MARK: - PDF Overview Export
@@ -415,3 +410,10 @@
 "overview.share.diagram" = "Bedradingsschema";
 "overview.share.pdf" = "Volledig rapport (PDF)";
 "overview.share.diagram.error" = "Diagram kon niet worden gegenereerd. Controleer je internetverbinding.";
+
+"editor.system.voltage_drop.label" = "Toegestane spanningsval";
+"editor.system.voltage_drop.hint.critical" = "3 % — voor kritische circuits zoals navigatie, bilgepomp en elektronica.";
+"editor.system.voltage_drop.hint.standard" = "5 % — evenwichtige standaard voor gemengde installaties.";
+"editor.system.voltage_drop.hint.noncritical" = "10 % — voor niet-kritische verbruikers zoals binnenverlichting.";
+"settings.voltage_drop.label" = "Toegestane spanningsval";
+"settings.voltage_drop.footnote" = "Geldt voor de rekenhulp en nieuwe systemen. Bestaande systemen houden hun eigen waarde.";

CableTests/CableTests.swift

@@ -354,8 +354,9 @@ struct CableTests {
         )
 
         // Minimum raw cross-section: (2×15×7.62×0.017)/(120×0.05) = 0.648mm²
-        // Metric: rounds to 0.75mm² (smallest standard ≥ 0.648)
-        #expect(metricMinCS == 0.75)
+        // Metric: 0.75mm² covers the voltage drop but only carries 16A (ISO 13297, 105 °C),
+        // which is below the 20A fuse for a 15A load, so ampacity forces 1.0mm² (20A).
+        #expect(metricMinCS == 1.0)
         // Imperial: AWG 18 (0.823mm² ≥ 0.648)
         #expect(imperialAWG == 18.0)
     }
@@ -412,4 +413,208 @@ struct CableTests {
         #expect(abs(actualDrop - expectedDrop) < 0.001)
         #expect(abs(actualLoss - expectedPowerLoss) < 0.001)
     }
+
+    // MARK: - Ampacity
+
+    /// A short run makes voltage drop irrelevant, so before ampacity was considered the
+    /// recommendation was 1.5mm² / AWG 16 next to a 50A fuse — a cable the fuse cannot protect.
+    @Test func shortHighCurrentRunIsSizedForAmpacityNotVoltageDrop() async throws {
+        // 0.5m, 40A, 12V → voltage-drop minimum is only 1.13mm², fuse is 50A
+        #expect(ElectricalCalculations.recommendedFuse(forCurrent: 40) == 50.0)
+
+        let metric = ElectricalCalculations.recommendedCrossSection(
+            length: 0.5, current: 40, voltage: 12, unitSystem: .metric
+        )
+        // 4.0mm² carries 45A < 50A, so 6.0mm² (60A) is the smallest protected size
+        #expect(metric == 6.0)
+
+        let imperial = ElectricalCalculations.recommendedCrossSection(
+            length: 0.5, current: 40, voltage: 12, unitSystem: .imperial
+        )
+        // AWG 12 carries 45A < 50A, so AWG 10 (60A) is the smallest protected size
+        #expect(imperial == 10.0)
+    }
+
+    @Test func fuseNeverExceedsCableAmpacity() async throws {
+        let scenarios: [(length: Double, current: Double, voltage: Double)] = [
+            (0.3, 15, 12), (0.5, 40, 12), (1, 30, 12), (1, 60, 12), (2, 25, 12),
+            (3, 10, 12), (5, 5, 12), (8, 20, 24), (12, 50, 24), (10, 100, 48),
+        ]
+
+        for scenario in scenarios {
+            let fuse = ElectricalCalculations.recommendedFuse(forCurrent: scenario.current)
+
+            for unitSystem in [UnitSystem.metric, UnitSystem.imperial] {
+                let crossSection = ElectricalCalculations.recommendedCrossSection(
+                    length: scenario.length,
+                    current: scenario.current,
+                    voltage: scenario.voltage,
+                    unitSystem: unitSystem
+                )
+                let ampacity = ElectricalCalculations.ampacity(
+                    forCrossSection: crossSection, unitSystem: unitSystem
+                )
+                #expect(
+                    ampacity >= fuse,
+                    "\(scenario.current)A over \(scenario.length)m: \(fuse)A fuse on a cable rated \(ampacity)A"
+                )
+            }
+        }
+    }
+
+    @Test func longRunsStayVoltageDropDriven() async throws {
+        // 3m, 10A, 12V → voltage drop needs 1.7mm², fuse is only 15A, so the drop still wins
+        let metric = ElectricalCalculations.recommendedCrossSection(
+            length: 3, current: 10, voltage: 12, unitSystem: .metric
+        )
+        #expect(metric == 2.5)
+        #expect(ElectricalCalculations.ampacity(forCrossSection: 2.5, unitSystem: .metric) == 35.0)
+    }
+
+    @Test func ampacityMatchesPublishedTables() async throws {
+        // ISO 13297 Table A1, 105 °C
+        #expect(ElectricalCalculations.ampacity(forCrossSection: 0.75, unitSystem: .metric) == 16.0)
+        #expect(ElectricalCalculations.ampacity(forCrossSection: 2.5, unitSystem: .metric) == 35.0)
+        #expect(ElectricalCalculations.ampacity(forCrossSection: 16.0, unitSystem: .metric) == 130.0)
+        // Between two standard sizes the smaller neighbour rates the cable
+        #expect(ElectricalCalculations.ampacity(forCrossSection: 3.0, unitSystem: .metric) == 35.0)
+        // ABYC E-11 Table 6A, 105 °C, outside engine spaces
+        #expect(ElectricalCalculations.ampacity(forCrossSection: 14, unitSystem: .imperial) == 35.0)
+        #expect(ElectricalCalculations.ampacity(forCrossSection: 6, unitSystem: .imperial) == 120.0)
+        #expect(ElectricalCalculations.ampacity(forCrossSection: -4, unitSystem: .imperial) == 445.0)
+        // AWG 20 is not covered by the table
+        #expect(ElectricalCalculations.ampacity(forCrossSection: 20, unitSystem: .imperial) == 0.0)
+    }
+
+    // MARK: - Voltage Drop Target
+
+    @Test func tighterTargetDemandsMoreCopper() async throws {
+        // 5m, 10A, 12V: 5% needs 2.833mm² → 4.0mm², 3% needs 4.722mm² → 6.0mm²
+        let standard = ElectricalCalculations.recommendedCrossSection(
+            length: 5, current: 10, voltage: 12, unitSystem: .metric
+        )
+        let critical = ElectricalCalculations.recommendedCrossSection(
+            length: 5, current: 10, voltage: 12, unitSystem: .metric, maxVoltageDropPercent: 3
+        )
+        #expect(standard == 4.0)
+        #expect(critical == 6.0)
+    }
+
+    @Test func looserTargetAllowsThinnerCableUntilAmpacityStops() async throws {
+        // 5m, 10A, 12V at 10%: drop needs only 1.417mm², but the 15A fuse still requires
+        // a cable rated for it, so 1.5mm² (25A per ISO 13297) is the floor.
+        let nonCritical = ElectricalCalculations.recommendedCrossSection(
+            length: 5, current: 10, voltage: 12, unitSystem: .metric, maxVoltageDropPercent: 10
+        )
+        #expect(nonCritical == 1.5)
+        #expect(ElectricalCalculations.ampacity(forCrossSection: 1.5, unitSystem: .metric) >= 15.0)
+    }
+
+    @Test func targetIsRespectedByResultingDrop() async throws {
+        for target in [3.0, 5.0, 10.0] {
+            let crossSection = ElectricalCalculations.recommendedCrossSection(
+                length: 8, current: 20, voltage: 12, unitSystem: .metric, maxVoltageDropPercent: target
+            )
+            let dropPercent = ElectricalCalculations.voltageDropPercentage(
+                length: 8, current: 20, voltage: 12, unitSystem: .metric, crossSection: crossSection
+            )
+            #expect(dropPercent <= target, "target \(target)% produced \(dropPercent)%")
+        }
+    }
+
+    @Test func defaultTargetStaysAtFivePercent() async throws {
+        #expect(ElectricalCalculations.defaultMaxVoltageDropPercent == 5.0)
+        let explicit = ElectricalCalculations.recommendedCrossSection(
+            length: 5, current: 10, voltage: 12, unitSystem: .metric, maxVoltageDropPercent: 5
+        )
+        let implicit = ElectricalCalculations.recommendedCrossSection(
+            length: 5, current: 10, voltage: 12, unitSystem: .metric
+        )
+        #expect(explicit == implicit)
+    }
+
+    @Test func systemStoresItsOwnTarget() async throws {
+        let system = ElectricalSystem(name: "Nav circuit", maxVoltageDropPercent: 3)
+        #expect(system.maxVoltageDropPercent == 3.0)
+        let defaultSystem = ElectricalSystem(name: "Cabin")
+        #expect(defaultSystem.maxVoltageDropPercent == ElectricalCalculations.defaultMaxVoltageDropPercent)
+    }
+
+    // MARK: - Derived Cable Sizes
+
+    /// `SavedLoad.crossSection` is always stored in mm², independent of the display unit.
+    private func makeLoad(current: Double, length: Double, crossSection: Double, voltage: Double = 12) -> SavedLoad {
+        SavedLoad(
+            name: "Load",
+            voltage: voltage,
+            current: current,
+            power: voltage * current,
+            length: length,
+            crossSection: crossSection
+        )
+    }
+
+    @Test func syncRepairsLibraryPlaceholderSizes() async throws {
+        // Library loads used to be stored with a hardcoded 1.0mm² at 10m
+        let load = makeLoad(current: 5, length: 10, crossSection: 1.0)
+        let changed = LoadCableSync.synchronize(loads: [load], maxVoltageDropPercent: 5)
+        // 5 % needs (2×5×10×0.017)/(12×0.05) = 2.833mm² → next standard size is 4.0mm²
+        #expect(changed == 1)
+        #expect(load.crossSection == 4.0)
+    }
+
+    @Test func syncRepairsCablesThatCannotCarryTheirFuse() async throws {
+        // 40A load → 50A fuse; 1.5mm² carries 25A (ISO 13297), so it has to grow to 6.0mm² (60A)
+        let load = makeLoad(current: 40, length: 0.5, crossSection: 1.5)
+        LoadCableSync.synchronize(loads: [load], maxVoltageDropPercent: 5)
+        #expect(load.crossSection == 6.0)
+        #expect(
+            ElectricalCalculations.ampacity(forCrossSection: load.crossSection, unitSystem: .metric)
+                >= ElectricalCalculations.recommendedFuse(forCurrent: load.current)
+        )
+    }
+
+    @Test func syncFollowsTheBudgetInBothDirections() async throws {
+        let load = makeLoad(current: 5, length: 10, crossSection: 1.0)
+
+        LoadCableSync.synchronize(loads: [load], maxVoltageDropPercent: 3)
+        // 3 % needs 4.72mm² → 6.0mm²
+        #expect(load.crossSection == 6.0)
+
+        LoadCableSync.synchronize(loads: [load], maxVoltageDropPercent: 10)
+        // 10 % needs 1.42mm², but the 7.5A fuse still needs a cable rated for it → 1.5mm²
+        #expect(load.crossSection == 1.5)
+    }
+
+    @Test func syncIsIdempotent() async throws {
+        let load = makeLoad(current: 10, length: 5, crossSection: 1.0)
+        #expect(LoadCableSync.synchronize(loads: [load], maxVoltageDropPercent: 5) == 1)
+        #expect(LoadCableSync.synchronize(loads: [load], maxVoltageDropPercent: 5) == 0)
+    }
+
+    @Test func syncLeavesIncompleteLoadsAlone() async throws {
+        let noLength = makeLoad(current: 5, length: 0, crossSection: 0)
+        let noCurrent = makeLoad(current: 0, length: 5, crossSection: 0)
+        #expect(LoadCableSync.synchronize(loads: [noLength, noCurrent], maxVoltageDropPercent: 5) == 0)
+        #expect(noLength.crossSection == 0)
+        #expect(noCurrent.crossSection == 0)
+    }
+
+    @Test func syncedSystemHasNothingLeftToReport() async throws {
+        let loads = [
+            makeLoad(current: 5, length: 10, crossSection: 1.0),
+            makeLoad(current: 40, length: 0.5, crossSection: 1.5),
+        ]
+        LoadCableSync.synchronize(loads: loads, maxVoltageDropPercent: 5)
+        #expect(LoadConfigurationStatus.evaluate(loads: loads) == nil)
+    }
+
+    @Test func onlyMissingInputsAreStillReported() async throws {
+        let loads = [
+            makeLoad(current: 0, length: 0, crossSection: 0),
+            makeLoad(current: 5, length: 2, crossSection: 2.5),
+        ]
+        #expect(LoadConfigurationStatus.evaluate(loads: loads) == .missingDetails(count: 1))
+        #expect(LoadConfigurationStatus.evaluate(loads: []) == nil)
+    }
 }

CableTests/LocalizationIntegrityTests.swift

@@ -0,0 +1,75 @@
+import Foundation
+import Testing
+@testable import Cable
+
+/// Guards the string tables themselves. A malformed `.strings` file still parses — a value
+/// spanning several lines silently swallows the entries behind it — and the app then renders
+/// raw keys like "tab.overview". These tests fail instead.
+struct LocalizationIntegrityTests {
+
+    private static let locales = ["Base", "de", "es", "fr", "nl"]
+
+    /// Keys rendered without a `defaultValue:`, so a missing entry is visible to users.
+    private static let keysWithoutFallback = [
+        "tab.overview",
+        "tab.components",
+        "tab.batteries",
+        "tab.chargers",
+    ]
+
+    private func table(for locale: String) throws -> [String: String] {
+        let bundle = Bundle.main
+        guard let url = bundle.url(
+            forResource: "Localizable",
+            withExtension: "strings",
+            subdirectory: nil,
+            localization: locale
+        ) else {
+            throw LocalizationTestError.tableMissing(locale)
+        }
+        let data = try Data(contentsOf: url)
+        let parsed = try PropertyListSerialization.propertyList(from: data, format: nil)
+        guard let table = parsed as? [String: String] else {
+            throw LocalizationTestError.tableMalformed(locale)
+        }
+        return table
+    }
+
+    @Test func everyLocaleProvidesTheKeysThatHaveNoFallback() async throws {
+        for locale in Self.locales {
+            let table = try table(for: locale)
+            for key in Self.keysWithoutFallback {
+                #expect(table[key] != nil, "\(locale): missing \(key), the UI would show the raw key")
+                #expect(
+                    table[key] != key,
+                    "\(locale): \(key) is not translated"
+                )
+            }
+        }
+    }
+
+    @Test func noValueSpansMultipleLines() async throws {
+        for locale in Self.locales {
+            let table = try table(for: locale)
+            for (key, value) in table {
+                #expect(
+                    !value.contains("\n"),
+                    "\(locale): \(key) contains a real newline; removing such an entry line by line corrupts the table"
+                )
+            }
+        }
+    }
+
+    @Test func retiredProKeysAreGone() async throws {
+        for locale in Self.locales {
+            let table = try table(for: locale)
+            let leftovers = table.keys.filter { $0.hasPrefix("cable.pro.") }
+            #expect(leftovers.isEmpty, "\(locale): dead PRO keys \(leftovers.sorted())")
+        }
+    }
+}
+
+private enum LocalizationTestError: Error {
+    case tableMissing(String)
+    case tableMalformed(String)
+}

CableUITestsScreenshot/LocalizedTabBarUITests.swift

@@ -0,0 +1,62 @@
+import XCTest
+
+/// Reproduces the regression where the tab bar rendered raw keys ("tab.overview") because a
+/// malformed entry in Localizable.strings hid every key behind it. The tab titles are looked up
+/// without a `defaultValue:`, so a broken table is immediately visible here.
+final class LocalizedTabBarUITests: XCTestCase {
+
+    override func setUpWithError() throws {
+        try super.setUpWithError()
+        continueAfterFailure = false
+        XCUIDevice.shared.orientation = .portrait
+    }
+
+    @MainActor
+    func testTabBarIsLocalizedInGerman() throws {
+        let app = XCUIApplication()
+        app.launchArguments = [
+            "--uitest-reset-data",
+            "--uitest-sample-data",
+            "-AppleLanguages", "(de)",
+            "-AppleLocale", "de_DE",
+        ]
+        app.launch()
+
+        openFirstSystem(in: app)
+
+        let expected = ["Übersicht", "Verbraucher", "Batterien", "Ladegeräte"]
+        for title in expected {
+            XCTAssertTrue(
+                app.buttons[title].waitForExistence(timeout: 15),
+                "Tab \"\(title)\" is missing — the German string table is not being read"
+            )
+        }
+
+        for rawKey in ["tab.overview", "tab.components", "tab.batteries", "tab.chargers"] {
+            XCTAssertFalse(
+                app.buttons[rawKey].exists,
+                "Tab bar shows the raw key \(rawKey) instead of a translation"
+            )
+        }
+    }
+
+    private func openFirstSystem(in app: XCUIApplication) {
+        let list: XCUIElement
+        if app.collectionViews["systems-list"].waitForExistence(timeout: 15) {
+            list = app.collectionViews["systems-list"]
+        } else {
+            list = app.collectionViews.firstMatch
+        }
+        XCTAssertTrue(list.waitForExistence(timeout: 15))
+
+        let firstCell = list.cells.element(boundBy: 0)
+        XCTAssertTrue(firstCell.waitForExistence(timeout: 10))
+
+        let cellButton = firstCell.buttons.firstMatch
+        if cellButton.exists {
+            cellButton.tap()
+        } else {
+            firstCell.coordinate(withNormalizedOffset: CGVector(dx: 0.5, dy: 0.5)).tap()
+        }
+    }
+}

CableUITestsScreenshot/SystemVoltageDropTargetUITests.swift

@@ -0,0 +1,64 @@
+import XCTest
+
+/// Verifies that a system exposes its voltage-drop budget and that picking a tighter
+/// target sticks, which is what drives cable sizing for that system.
+final class SystemVoltageDropTargetUITests: XCTestCase {
+
+    override func setUpWithError() throws {
+        try super.setUpWithError()
+        continueAfterFailure = false
+        XCUIDevice.shared.orientation = .portrait
+    }
+
+    @MainActor
+    func testVoltageDropBudgetIsSelectableInSystemEditor() throws {
+        let app = launch(arguments: ["--uitest-reset-data", "--uitest-sample-data"])
+
+        openFirstSystem(in: app)
+
+        let systemTitle = app.buttons["system-title-button"]
+        XCTAssertTrue(systemTitle.waitForExistence(timeout: 15))
+        systemTitle.tap()
+
+        let picker = app.segmentedControls["system-voltage-drop-picker"]
+        XCTAssertTrue(picker.waitForExistence(timeout: 15), "System editor must offer a voltage drop budget")
+
+        let standard = picker.buttons["5 %"]
+        XCTAssertTrue(standard.waitForExistence(timeout: 5))
+        XCTAssertTrue(standard.isSelected, "New systems start at the 5 % default")
+
+        let critical = picker.buttons["3 %"]
+        XCTAssertTrue(critical.exists)
+        critical.tap()
+        XCTAssertTrue(critical.isSelected, "Picking 3 % must stick")
+    }
+
+    // MARK: - Helpers
+
+    private func launch(arguments: [String]) -> XCUIApplication {
+        let app = XCUIApplication()
+        app.launchArguments = arguments
+        app.launch()
+        return app
+    }
+
+    private func openFirstSystem(in app: XCUIApplication) {
+        let list: XCUIElement
+        if app.collectionViews["systems-list"].waitForExistence(timeout: 15) {
+            list = app.collectionViews["systems-list"]
+        } else {
+            list = app.collectionViews.firstMatch
+        }
+        XCTAssertTrue(list.waitForExistence(timeout: 15))
+
+        let firstCell = list.cells.element(boundBy: 0)
+        XCTAssertTrue(firstCell.waitForExistence(timeout: 10))
+
+        let cellButton = firstCell.buttons.firstMatch
+        if cellButton.exists {
+            cellButton.tap()
+        } else {
+            firstCell.coordinate(withNormalizedOffset: CGVector(dx: 0.5, dy: 0.5)).tap()
+        }
+    }
+}