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.
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.