Can I use main breaker as battery disconnect?
I am getting ready to purchase and install a battery disconnect. I am very familiar with residential wiring and electricity but I have not familiarized myself with rv wiring. Could I just use the ...
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The biggest problem is that the 120 VAC breakers are only rated for a few amps, and they are rated at VAC, not the direct current, that tends to ark when exposed to high amperage fault.
Your home is limited to the fault current that can go through the typical #6 wire going from a 10 KW transformer to the home, and it limited to about 25,000 amps maximum fault current. A truck battery can supply more than 25,000 amps for a couple of seconds, and typically will require a fuse to make sure that the device does trip in a high amperage fault.
The 480 volt rated Square D circuit breakers are also rated at 48 VDC, and you could use that type of breaker, but they are the larger frame 'I line' breakers, about 1.5" wide and 6" long. Many times a electric car conversions will have a I-Line circuit breaker in it, rated at 300 amps or so.
You can find DC rated circuit breakers at a place like West Marine. I would rather use a automatic reset circuit breaker like found at Napa Auto, or your local auto parts store. They come in 15 amp to 60 amp ratings with 5 amp steps. Only about $3 - $10 each. In my RV, the generator starter wire is protected by a pair of the 30 amp breakers with a bussbar between them, so it is rated at around 60 amps. You can gang them together.
Good luck,
Fred.
Your home is limited to the fault current that can go through the typical #6 wire going from a 10 KW transformer to the home, and it limited to about 25,000 amps maximum fault current. A truck battery can supply more than 25,000 amps for a couple of seconds, and typically will require a fuse to make sure that the device does trip in a high amperage fault.
The 480 volt rated Square D circuit breakers are also rated at 48 VDC, and you could use that type of breaker, but they are the larger frame 'I line' breakers, about 1.5" wide and 6" long. Many times a electric car conversions will have a I-Line circuit breaker in it, rated at 300 amps or so.
You can find DC rated circuit breakers at a place like West Marine. I would rather use a automatic reset circuit breaker like found at Napa Auto, or your local auto parts store. They come in 15 amp to 60 amp ratings with 5 amp steps. Only about $3 - $10 each. In my RV, the generator starter wire is protected by a pair of the 30 amp breakers with a bussbar between them, so it is rated at around 60 amps. You can gang them together.
Good luck,
Fred.
