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tmartin000 avatar image

Chassis ground with no real chassis in Truck camper

Obviously the whole chassis ground thing has a purpose. But truck campers have no real chassis. So my plan is to run a 6ga green wire from the rear where the Vic 120/3000 inverter and 4 lithium batts and solar controller reside. That 6ga starts at a bus bar where I have the Vic 250/80 controller and the Vic Inveter/charger only. Then the 6ga runs 20’ forward is a chassis bar that is inches away from the bat NEG bar and neutral 120vAC bar.

Is that sufficien?

Grounding
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Kevin Windrem answered ·

The purpose of a chassis ground connection is to safely route fault currents away from people. The chassis ground (aka safety ground) bonds to the AC neutral at the service entrance. It is also connected to a ground rod to drain static electricity only. Without a proper safety ground, should a fault occur that connects an AC hot lead to the chassis, the chassis would be elevated to the AC line voltage and become a shock hazzard. With a proper safety ground, a circuit breaker (or fuse) trips to deenergize the fault circuit.

While 12 or 24 volt DC circuits are less lethal than 120 or 220 volts AC, there are still opportunities for unhealthy conditions or circuit damage if the fault current isn't redirected and circuit breaker/fuse tripping.

The situation is really no different in an RV/camper than a home. There are always metal appliances or even the vehicle frame, windows, door handles, etc. that could become the source of lethal voltages.

The DC common and AC safety ground must all be bonded to the vehicle frame somehow. The shortest path is usually best.

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tmartin000 answered ·

Perfect, thank you very much Kevin! I believe this should be close enough....If I add two 6ga wires in parallel, we are more than covered. I'd rather over-protect than under... Besides, its not much more $$$. Funny, I see installs where people do what is cheaper and easier, but I really don't want that. :)


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Kevin Windrem avatar image
Kevin Windrem answered ·

6 AWG should be sufficient. I think US National Electrical Code rates it for 100 amps or less. Other countries may have different requirements.

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tmartin000 answered ·

Well, there is no metal chassis in a truck camper. So, I will answer my own question and realize that the only neutral ground bar is 20’ away and that’s where I must run my 6ga green chassis ground wire. Incidentall, the largest accepted wire gauge in/on that particular bus bar, is only 6ga. So, I will re-ask my question....is that sufficient? If I must add a thicker wire, I could run two and attach them BOTH to opposite ends of that neutral buss bar.

Thanks for your help.

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