Wiring List — Length Adjustments
The Wiring List tab (accessible from the top navigation bar) displays every electrical connection in your harness drawing as a clean, sortable, exportable table. Each row represents a wire running from one connector pin to another, specifying wire color, gauge, twist group, and calculated physical cut length.
At the very top of the table is an interactive toolbar formatted into setting mini-cards, allowing you to dial in real-world length adjustments before printing or exporting to Excel/PDF. Wiringly calculates the exact cut lengths for your physical build automatically.
[!TIP] All adjusted lengths are automatically rounded up to the next 10 mm. For example, 361 mm becomes 370 mm, 370 mm stays 370 mm, and 371 mm becomes 380 mm. You will never be asked to cut an awkward 363 mm wire on the bench.
The Four Length Adjustments
1. 📐 Routing Margin (Always Active)
| Default | Scope | Purpose |
|---|---|---|
| 5 % | All Wires | Baseline routing curvature & harness branch bends |
The geometric length Wiringly measures on the digital canvas is the direct or routed distance between two connector endpoints. In physical installations, wires curve around corners, follow chassis mounting brackets, and branch off inside harness breakouts.
The Routing Margin adds a baseline percentage allowance across all wires to ensure no wire is cut short due to physical harness geometry.
- When to adjust:
- Increase to 10–15%: For complex engine bay looms or tight chassis routing with many 90° bends.
- Decrease to 2–3%: For simple, flat panel assemblies or short bench testing setups.
2. 🔀 Twisted Pair Extra (On by Default)
| Default | Scope | Purpose |
|---|---|---|
| 7 % | Twisted Wires Only (TW1, TW2, etc.) | Compensates for wire length consumed by twisting helical pairs |
When two or more conductors are twisted together into a twisted pair or bundle (e.g. CAN High / CAN Low, differential sensor signals, Ethernet, or knock sensor pairs), the twisting action consumes additional wire length compared to a straight parallel run.
Because two wires spiraling around each other travel a longer helical path, cutting them to standard straight length results in a bundle that is physically too short. Twisted Pair Extra applies a dedicated percentage multiplier (default +7%) specifically to wires assigned to a twist group.
- When to adjust:
- Default 7%: Perfect for standard 1-inch (25 mm) twist pitch CAN bus and sensor pairs.
- Increase to 10–12%: For high-density, tight-pitch twisted pairs (e.g. military/motorsport specification data lines).
- Toggle Off: If your harness contains no twisted pairs or if your geometric routing path already accounts for twist length.
3. 🌀 Concentric Twisting (Optional)
| Default | Scope | Purpose |
|---|---|---|
| 10 % | Entire Harness | Global spiral lay allowance for concentric motorsport looms |
In high-end motorsport and aerospace wiring, harnesses are constructed using concentric lay construction — where central core wires are surrounded by outer layers of conductors wrapped in alternating spiral directions.
Because conductors in outer layers travel along longer spiral paths than central core conductors, concentric twisting requires a global length multiplier across the entire harness bundle.
- When to use: Enable this option when building military or high-tier motorsport looms specified with concentric lay construction.
4. 🔄 Service Loop (On by Default)
| Default | Scope | Purpose |
|---|---|---|
| 40 mm / end | All Wires (2 ends per wire) | Maintenance slack for re-stripping and crimping |
A Service Loop is deliberate slack left at connector termination points. It provides critical benefits during harness assembly and field maintenance:
- Terminal Re-crimping: If a pin is damaged or mis-wired during assembly, extra wire is available to strip and re-crimp without replacing the entire conductor.
- Strain Relief: Slack prevents vibration from pulling the wire tight against connector backshells or strain relief boots.
- Future Modifications: Allows connectors to be repinned or replaced over the service life of the vehicle.
Because every wire connects between two endpoints, the total added service loop length per wire is Service Loop × 2 (e.g., 40 mm × 2 = +80 mm total extra per wire).
Complete Calculation Formula
Wiringly applies length adjustments in a precise, deterministic sequence:
adjustedLength = rawGeometricLength
× (1 + routingMargin / 100)
× (1 + (isTwisted && twistedExtraEnabled ? twistedExtraPct / 100 : 0))
× (1 + (concentricEnabled ? concentricPct / 100 : 0))
+ (serviceLoopEnabled ? serviceLoopMmPerEnd * 2 : 0)
finalCutLength = Math.ceil(adjustedLength / 10) * 10
[!NOTE] Under the adjusted length column in the Wiring List, Wiringly displays the raw geometric length in small text so you can inspect the exact breakdown of added margins.
Recommended Starting Settings
| Harness Type | Routing Margin | Twisted Pair Extra | Concentric Twisting | Service Loop |
|---|---|---|---|---|
| Simple Panel / Relay Box | 3–5 % | Off | Off | 30–40 mm |
| Standard Automotive Loom | 5–10 % | 7 % (on TW wires) | Off | 40 mm |
| Motorsport Engine Harness | 8–12 % | 7–10 % (on TW wires) | 10 % | 40–50 mm |
| Race Car Chassis Loom | 10–15 % | 7 % (on TW wires) | Off | 50–60 mm |
| Marine & Off-Road | 10 % | 7 % (on TW wires) | Off | 50–80 mm |
Exporting & Printing Reports
When you export your project via Export to Excel or Export PDF, the exported cut lists automatically use the adjusted and rounded final lengths.
The summary header of every exported Excel sheet includes an audit log of active length settings, guaranteeing total transparency during physical harness assembly.