RV 12V ground question

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  #1  
Old 11-13-15, 06:33 AM
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RV 12V ground question

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Size:  18.5 KBI am stumbling through redoing the wiring on my RV. Not always sure of schematics I have put in 2 negative to chassis wires. one from the battery and one from the 12V neg buss bar.

I am sure I have sized the wire right so that is not an issue.

Will the second neg to chassis from the buss bar cause any issues?
 
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Old 11-14-15, 12:26 AM
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The second ground wire should not cause any problems.

The wiring you use needs to be able to handle the expected load with minimal voltage drop.
Basic house battery supply wire should be #4 or so..... depending on the length.

Don't forget.... you need catastrophic protection fuses at the batteries to protect the wiring. I'd use #4 battery cable with a 100A fuse for a generic setup.
 
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Old 11-14-15, 03:14 AM
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One other thing. Don't forget the engine must be grounded to the chassis as well.
 
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Old 11-14-15, 04:58 AM
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Is this a travel trailer? The grounds/neutrals are not connected to the frame/chassis AFAIK. This bond is made when you connect to shore power.

All my bus bars are attached to wood..

If its a driveable RV then it should be the same I would think..
 

Last edited by lawrosa; 11-14-15 at 05:23 AM.
  #5  
Old 11-14-15, 07:16 AM
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Many years on the internet and I still don't give enough info Yes this is a fiberglass motorhome based on a 1993 Toyota pickup.

The OE wire is #8 and runs about 30 feet! I plan on using a #4 THHN and rerouting I will get the length down to about 18 feet! 100 A fuse seems like over kill, I have 50A on order?

Thanks for the input, don't go away I am not done yet
Jim
 
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Old 11-14-15, 09:12 AM
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A fuse is placed at the battery ONLY to protect the wiring from the battery to breakout location.

I mentioned I use #4 wiring and a 100A fuse. That's because I want to limit the amount of power drawn thru the wire in case of direct short to ground. I take the #4 wiring to a multiple fuse block where the other loads are connected with their own fuse.

You can use any size fuse you want on it.
You still need to use a proper sized fuse for each piece of equipment or circuit.

When dealing with 120v shore power.... the neutral and ground are not connected together.
 
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