12V distribution question
Here is a sketch of what I want to do for 12V for review. Will the #8 wire with a 40A breaker from the isolater be an issue? The #8 wire is original. The schematic for the PD9145A shows 18" max to...
Forum Discussion
The general setup looks more or less reasonable, but there are several details I don't really like.
I would suggest using heavier wire for your six inch wires, or even a little buss bar. If you don't have a main fuse on the fuse panel, note that with the setup you show the power you have available there will have rather significant differences depending on whether you're running off the house battery (50A max), or plugged into shore power (95A max in theory). 95A is more than 6 gauge wire can carry safely. Some of the other wires could in theory under some (rare) circumstances also be overloaded when multiple sources are on line at the same time.
The 50A breaker near the junction point on the battery wire is pointless and unnecessary. Leave the breaker or fuse as close to the battery as possible. Likewise, the breaker on the line to the isolator is unnecessary if you have a breaker or fuse of an appropriate size close to the chassis battery (as you should).
The 6 gauge and 8 gauge wires to the battery and isolator are rather long for their size in terms of voltage drop. Heavier wires will help with battery charging in particular. If possible, I would prefer to mount the converter at or near the battery rather than at the fuse panel, but that's possibly more a personal preference than anything. (If you have an "emergency start" switch associated with the isolator, you should have much heavier wire between the batteries and the isolators and much larger fuses/circuit breakers for it to be very effective. The starter needs much more than 40A.)
Do you have a battery disconnect switch planned? That would presumably go between the battery and the rest of the world.
Do you have a generator installed in the RV? That would need another heavy wire lead from one or the other of the batteries, of course with an appropriate fuse or circuit breaker.
I would suggest using heavier wire for your six inch wires, or even a little buss bar. If you don't have a main fuse on the fuse panel, note that with the setup you show the power you have available there will have rather significant differences depending on whether you're running off the house battery (50A max), or plugged into shore power (95A max in theory). 95A is more than 6 gauge wire can carry safely. Some of the other wires could in theory under some (rare) circumstances also be overloaded when multiple sources are on line at the same time.
The 50A breaker near the junction point on the battery wire is pointless and unnecessary. Leave the breaker or fuse as close to the battery as possible. Likewise, the breaker on the line to the isolator is unnecessary if you have a breaker or fuse of an appropriate size close to the chassis battery (as you should).
The 6 gauge and 8 gauge wires to the battery and isolator are rather long for their size in terms of voltage drop. Heavier wires will help with battery charging in particular. If possible, I would prefer to mount the converter at or near the battery rather than at the fuse panel, but that's possibly more a personal preference than anything. (If you have an "emergency start" switch associated with the isolator, you should have much heavier wire between the batteries and the isolators and much larger fuses/circuit breakers for it to be very effective. The starter needs much more than 40A.)
Do you have a battery disconnect switch planned? That would presumably go between the battery and the rest of the world.
Do you have a generator installed in the RV? That would need another heavy wire lead from one or the other of the batteries, of course with an appropriate fuse or circuit breaker.
