RV & Van Wire Color Codes: 12V DC Wiring Standards
Following a consistent color code makes your van wiring safe to work on and faster to troubleshoot — especially years later when you've forgotten where every wire goes.
DC 12V color conventions
The ABYC E-11 standard (the governing document for recreational vehicle and marine 12V wiring) specifies:
| Wire function | Color |
|---|---|
| DC positive (unfused, high current) | Red |
| DC positive (fused circuits) | Red or color-coded by circuit |
| DC negative return | Black or Yellow |
| DC grounding conductor | Green |
In practice, most van builders use:
- Red for main positive cables and positive bus bar connections
- Black for main negative cables and negative bus bar connections
- Green (or green/yellow stripe) for chassis ground and safety ground conductors
- Other colors (blue, orange, purple, white) for individual 12V load circuits in the fuse block
Circuit-specific colors (common van build conventions)
| Circuit | Common color |
|---|---|
| Main battery positive | Red |
| Main battery negative | Black |
| Solar PV positive | Red |
| Solar PV negative | Black |
| 12V fridge | Orange or blue |
| Lighting | White or yellow |
| Fan/vent | Blue or purple |
| Water pump | Green (non-grounding) or orange |
| USB/device charging | Any distinct color |
Using different colors for different circuits makes it easy to trace a specific load from fuse block back to its device — useful when troubleshooting "what's feeding this wire?"
AC 120V color conventions (NEC/shore power)
If you have a shore power inlet and AC distribution, follow NEC household wiring colors:
| Wire function | Color |
|---|---|
| Hot (live) | Black |
| Neutral | White |
| Safety ground | Green or bare copper |
On a 30A shore power inlet: the hot wire is black (NEMA TT-30 plug's hot blade), neutral is white, ground is green.
Never use the same color for DC and AC circuits in the same build — a van with both DC and AC wiring should make them visually distinct to prevent dangerous confusion.
Where van builds commonly deviate
Automotive conventions vs ABYC
Automotive wiring often uses black for ground (same as ABYC), but may use a variety of colors for positive leads without a strict standard. Some van builders wire the 12V DC fuse block using leftover automotive wire in arbitrary colors — this works fine as long as everything is labeled.
The "any color with a label" school
Some very tidy builds use a single wire color (black) for all DC runs and rely entirely on labels at each end. This is allowed by ABYC as long as circuits are identifiable at terminals. It's also confusing to anyone who doesn't know the build — including you two years later.
Recommendation: Use red for positive and black for negative at minimum. Color-code fuse block circuits for convenience.
Practical tips
Label both ends. Whatever color you use, label each wire at both ends — at the fuse/breaker and at the device. Use heat-shrink labels or flag labels with a permanent marker.
Use wire labels consistently. A label maker with shrink-tube labels is the gold standard. Painters tape with a marker works in a pinch.
Document your system. Draw or photograph your wiring diagram with wire colors noted. Future you (and anyone who ever works on the van) will thank you.
Consistent lug colors. Many builders use red ring terminals for positive and black for negative at connection points — adds a visual layer without relying on wire color alone.