I have a 3000W inverter connected to a 24V battery bank and I'm trying to figure out the right cable size. The math shows I would need about 125 amps, which suggests a 1/0 cable would be fine. However, when I use several online cable sizing calculators, they recommend a 4 AWG cable for this setup. I'm puzzled about this discrepancy. Also, the total length of the cable run is under 10 feet and it won't be in a high-temperature or enclosed space. What am I missing?
1 Answer
Honestly, I wouldn't rely too much on those online calculators for electrical work. It's best to stick to established standards to avoid any issues later. In the US, for instance, we have the NEC guidelines which provide proper ampacity charts. First up, for your 3000W at 24V setup, you should calculate your over-current protection size, which would bring you to about 157 amps. The next common size for that would be a 175A breaker. For cabling, you'll want to go with a 2/0 AWG copper wire to handle the load safely. In solar setups, 2/0 for 175A is common, whereas for 12V and 24V systems, you'd often see 4/0 at 250A. Just make sure to use cables rated properly by the manufacturer, especially since some lower voltage systems might have their own specific ampacity standards. And don't forget about terminations; proper terminations are crucial, as not all terminals support fine strand wire without additional techniques like using ferrules.
Can you elaborate on 'terminate properly'? What does that involve?
Yeah, I hear you! I also think more brands should offer 24V models instead of those bulky 12V setups.