Wiring an inverter correctly is mostly about three things: short heavy cable, the right fuse, and proper grounding. Here's the step-by-step for a US van or RV build, building on the inverters & 120V power guide.
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Step 1: Mount it close to the battery
Inverter cable carries the highest current in the system — at 2,000W, roughly 190A. Every foot of cable at that current adds cost and voltage drop, so mount the inverter as close to the battery/bus bars as the install allows, in a ventilated spot (inverters generate heat under load and need airflow).
Step 2: Run the DC cable
Size the positive and negative DC cables for the inverter's full-load current — for a 2,000W inverter, that's 2/0 AWG or larger. Both cables run from the inverter to the bus bars (not directly to the battery terminals). See the AWG wire size chart for other sizes.
Step 3: Add the fuse
A dedicated fuse goes on the positive DC cable, sized to the inverter's full-load current:
- Under ~1,000W: an ANL or MIDI fuse rated appropriately.
- 2,000W+: typically an ANL or Class T fuse rated 200-250A, placed as close to the bus bar/battery as practical.
See RV fuse sizing for the full method.
Step 4: Ground the inverter
- Chassis ground: connect the inverter's case/ground terminal to the vehicle's single chassis bonding point — the same one used for the rest of the 12V system.
- AC output ground: if the inverter feeds fixed 120V outlets, the AC ground conductor follows the same grounding/bonding scheme as the rest of the AC system, per NEC Article 551.
The AC output side needs NEC-compliant wiring
Running the inverter's 120V output to fixed outlets means that wiring — breakers, GFCI, grounding — falls under NEC Article 551. The DC input side (steps 1-3) is DIY-friendly; the AC output side should be installed or inspected by a licensed electrician.
Step 5: Add a remote switch (optional but recommended)
Inverters draw power just being switched on (standby draw). A remote on/off switch, mounted somewhere convenient, lets you fully power down the inverter when you're not using AC — without crawling to reach the unit itself.
Step 6: Test before relying on it
With the inverter wired and fused, test with a small known load (a lamp, a phone charger) before connecting anything sensitive. Confirm the battery monitor shows the expected current draw, and check cable temperatures after a few minutes under load — warm is normal, hot is not.
Review both sides of the inverter installation
On the DC side, document operating current at the lowest design voltage, cable routing and length, protection, isolation, terminal preparation and ventilation. On the AC side, distinguish standalone receptacles from a vehicle distribution system supplied by shore power as well as the inverter. Those arrangements need different design decisions.
For an illustrative 1,500W load, 90% assumed efficiency and 12V input give about 139A DC. At 11V the same assumptions give about 152A. This is a load calculation, not an AWG or fuse recommendation. Use the inverter manual and the actual cable installation to complete the design.
Can a neutral-ground bond be added to stop a tester warning?
Do not add or remove a bond by guesswork. Switching, grounding and GFCI operation depend on the inverter and supply modes. Have a qualified installer verify the full arrangement, including shore-to-inverter transfer. Never feed shore and inverter outputs together or backfeed through an exposed-pin lead.
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Jack Kennedy is a self-builder who has built two vans. He created Roam Wired to simplify conversion planning and share free tools, supported by affiliate links.
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