What Wire Gauge
for 2000W?
Don't set your van on fire. Technical analysis according to ISO 10133 norms.
A 2000W 12V/110V-220V inverter is the standard for powering a coffee maker, hair dryer, or power tools. But beware, 2000W at 12V is a massive current (over 160 Amps!).
Undersizing this cable doesn't just cause a voltage drop: it causes severe heating that can melt the insulation and start a fire. Here is the math behind this wiring.
The Math: Ohm's Law
Let's calculate the real current. The formula is simple: I (Amps) = P (Watts) / V (Volts).
However, an inverter is not 100% efficient (typically 85-90%). We factor in a 15% loss. Moreover, while a Lithium (LiFePO4) battery sits at ~12.8V, a Lead-acid battery drops to 11.5V under heavy load.
- Without loss: 2000W / 12V = 166.6A
- With loss (85% eff): 166.6A / 0.85 = 196A peak!
Conclusion: Your cable must handle a constant 200 Amps.
What the Standards Say (ISO 10133 / ABYC)
US and European standards limit voltage drop to 3% generally, but for critical heavy-draw components like inverters, aiming for less than 1% drop is highly recommended to prevent heat.
| Round Trip Distance | Minimum Required Gauge |
|---|---|
| Less than 3 feet (1m round trip) | 1/0 AWG (50 mm²) |
| 3 to 6 feet (2m round trip) | 2/0 AWG (70 mm²) |
| More than 6 feet | 4/0 AWG (95 mm²) (or reconsider layout) |
MEGA Fuse Sizing
The golden rule of RV electrical: The fuse protects the cable, not the appliance.
It must be placed as close to the battery positive terminal as physically possible. For a max draw of 196A and a 1/0 or 2/0 AWG cable, a 250A or 200A MEGA fuse is mandatory.
Avoid cheap automatic breakers (car audio style) for a 2000W inverter: they wear out from high thermal cycles and trip prematurely. Use an authentic bolted MEGA fuse.
I'm Leo, an engineer and vanlifer since 2019. I've installed and tested the electrical systems in 3 different vans. Every recommendation on this site is based on hands-on experience, not copied spec sheets. I have no commercial ties with manufacturers — I only recommend what I use or would install in my own van.
Frequently Asked Questions
What cable size for a 2000W inverter?+
For a 2000W inverter at 12V (~170A), you need a minimum of 50mm² under 1m, or 70mm² beyond. With the 3% max voltage drop rule, the gauge increases with distance.
Do I calculate round-trip cable length?+
Yes, absolutely. Current flows through the cable both ways. If your battery is 1m from the inverter, the cable length to consider is 2m (1m x 2). This is a very common mistake that under-sizes the installation.
Fuse or breaker to protect an inverter?+
MEGA bolt-down fuse for high currents (100A+). Thermal breakers of the audio type wear out from repeated thermal cycles and end up tripping for no reason. Size the fuse at 125% of max rated current.