DrewE wrote:
DRTDEVL wrote:
4/0 is 0.46"
2 awg is 0.2576"
2x 2awg is 0.5152"
I believe this will pass the same, if not more, power capacity, while saving money. After all, 4/0 cable is about $4/foot and 2 awg is less than $2/foot. I'll need about 10 feet each for the positive and ground, so this is the difference of $20 in cabling for the same capacity.
Unless I am wrong, then someone correct me. I don't want to burn the thing down.
It's not the same, for a couple of reasons. First, you're comparing diameter rather than cross-sectional area, which of course for a round wire is pi r^2. Here is a nice chart where the math is done for you; 2 AWG has a cross-sectional area of 42.4mm^2, and 4/0 has a cross-sectional area of 107 mm^2. Two and a half 2 AWG wires would be just about equivalent.
The second reason they are not equivalent is perhaps of greater importance. If one of the ground wires were to work lose or break or corrode and have a (relatively) high resistance, you may never notice the difference in performance but the one remaining good one would carry most or all of the current and be overloaded. Even under good conditions there is likely to be some current imbalance as the impedances will not be precisely equal, and it doesn't take very much resistance at all to cause a fairly significant difference for a chunk of wire.
Can't the grounds connect to the trailer frame itself? I wouldn't think you'd need ten feet, just a couple feet at the battery bank and a couple feet at the inverter.
Exactly the info I need. I'll hit them both with 4/0 then.
As for the ground location, there really isn't a good spot on the frame extensions at the rear of the coach to attach a ground, and there is already a ground bus bar near the battery box that I was going to bolt it to (where the factory generator ground is, among other things. I will then add another 4/0 from the bar to the battery bank in conjunction with the 2 awg that already grounds to the battery. This should fix the issues you noted, with the 4/0 carrying the main load and the 2 awg carrying all the little loads from the 12v appliances.
