Inverter Wiring Safety in a Van or RV
The inverter handles the highest current in your van system. Getting the wiring right is the difference between a safe, reliable system and a fire risk.
Why inverter wiring is highest-stakes
A 2,000W inverter at 12V draws up to 185A from the battery. For comparison, a 30A fuse block feeds all your small 12V loads at 30A total. The inverter cable carries 6× that current.
At 185A:
- A loose connection generates significant heat
- An undersized wire overheats and can ignite insulation
- A short circuit on the DC input cable can deliver thousands of amps from the battery
All wiring rules apply more critically here than anywhere else in your build.
DC input wiring
Cable sizing
| Inverter size | Continuous current | Cable (up to 4' run) | Cable (up to 8' run) |
|---|---|---|---|
| 1,000W | ~95A | 1/0 AWG | 2/0 AWG |
| 2,000W | ~185A | 2/0 AWG | 4/0 AWG |
| 3,000W | ~275A | 4/0 AWG | Not recommended at 12V |
Always verify with your inverter manufacturer's documentation — they specify minimum cable sizes.
Cable type: Welding cable (SAE J1127) or marine-grade stranded copper. Flexible enough to route and vibration-resistant.
Fusing
A fuse on the positive DC input cable, within 18 inches of the battery positive terminal. Use:
- ANL fuse: Blue Sea Systems or Littelfuse ANL fuse holders. Rated for battery short-circuit current. Size at the wire's ampacity or slightly above (not the inverter's power rating).
- Class T fuse: Higher interrupting capacity — used in serious installations where fault current is very high (large battery banks).
For a 2,000W inverter with 2/0 AWG cable: 200A ANL fuse. For a 2,000W inverter with 4/0 AWG cable: 250A ANL fuse.
Cable length
Keep the DC run as short as physically possible — battery positive to inverter positive should ideally be under 36 inches. Same for negative. Mount the inverter as close to the battery as the build allows.
Connection at inverter
Most inverters have 5/16" or 3/8" stud terminals. Use the correct ring terminal size and torque to specification. A loose inverter terminal can arc at high current.
AC output wiring
The inverter's 120V AC output is wired like household wiring: hot (black), neutral (white), ground (green or bare). Use 14 AWG or 12 AWG stranded wire depending on the current requirements of the circuits you're feeding.
Grounding the AC output: Connect the inverter's AC ground terminal to the van chassis or to your negative bus bar (which is connected to chassis). This provides safety ground for AC outlets — required for proper GFCI function if you install GFCI outlets.
Separate AC and DC runs: Where possible, run AC output wiring separately from DC wiring to minimize interference, particularly for audio equipment.
Inverter mounting location
Clearance: 4–6 inches on all sides for airflow over heat sinks. Inverters generate significant heat under load — blocking airflow causes thermal shutdown and eventually premature failure.
Mounting surface: Mount on a metal surface (van body panel, steel plate) not directly on wood. Wood is combustible; metal dissipates heat and doesn't ignite.
Orientation: Most inverters are designed to mount vertically or horizontally per their documentation. Check — some models must be mounted a specific way for proper cooling.
Proximity to battery: Close to battery (short DC cables) but not inside an enclosed battery box — inverters need ventilation, and battery boxes in some configurations vent hydrogen or other gases.
No flammables nearby: Keep the area around the inverter clear. Don't store paper, cloth, or flammable materials within 12 inches.
Remote on/off switch
Most quality inverters (Victron MultiPlus, Aims, WZRELB) have a remote on/off port. Wire a switch in the cab area so you can kill the inverter without reaching into the van interior. Useful for driving (no need for inverter when vehicle is moving) and for reducing standby draw when not needed.
Common inverter wiring mistakes
Too-small DC cable: The most common. Check your cable gauge against the inverter's recommendation. A hot cable is a fire waiting to happen.
No fuse or wrong fuse: Must be an ANL or Class T fuse, within 18" of battery. A generic automotive blade fuse cannot interrupt the fault current that a battery can deliver.
Grounding the AC neutral to chassis: Some inverters auto-bond neutral to ground (transfer switch function). Others require you to do this manually. Read your inverter documentation. An unbonded neutral means GFCI outlets won't trip on faults.
Inverter in enclosed space: Inverters must have airflow. A sealed cabinet without ventilation causes thermal shutdown within minutes of load.