grounding to the trailer

[westend1530]

I am looking at my trailer running light wiring and at one point the ground wire was grounded to the trailer. Is this necessary if it is well grounded coming from the truck? I guess it can't hurt, but it looks like it has pulled free twice.


Thanks

[westend1530]

Ok I think i understand this now. Please tell me if this is not correct

There is a wire that is connected to the trailer frame that is the ground. This wire is very rusted and loose, so someone has tried to find another place to connect the ground wire. If the frame is not grounded then the lights will not work. The taillight fixtures are grounded through the skin of the trailer.

[westend1530]

I ground down where the ground wire contacts the frame and made a better connection. then tightened everything down. I ran a wire from that to the back of the trailer light housing and checked the ohm's. There was still a lot of resistance. I guess there is too much rust and the skin is to loose to make a good connection. If I want the lights to work I will have to run a ground wire back there.

Anything else I should check

[vikx]

When in doubt, ground it again. My Hanson has 5 grounds, the main and smaller skin to frame grounds.

You might try cleaning the sockets and the screws attaching the light housing to the skin.

[cowcharge]

On my'76 there were frame ground wires on everything, 5 or 6 different ones, one under the kitchen, one under the fridge/furnace, one under the left rear for the tail/marker lights, one under the left front for grounding the 110v box, one right rear for the water pump... I guess by then they had given up on skin grounding.

[westend1530]

I just ran a new ground wire from the skin to the frame, running lights now work like a champ.

Thanks

[bagpipeswest]

im going to throw this one out there.

If I ground the trailer to make my clearence lights work, how will that interfere with the grounding of my 120VAC breaker box, my inverter, my conveter ,

in a nut shell , does it matter if I ground the A/C and the D/C on the frame at the same time?

BM

[schweetcruisers]

According to the 3 Electrical Engineers I consulted, you really want all the grounds run to one point. If you decide to have multiple grounds you need you run wire between them, to tie them together.

[bagpipeswest]

that make sence.

thanks again

cheers
BM

[vikx]

Schweet's comment makes sense, but it's not necessary to wire all the grounds together on a trailer. The frame is one big ground. So, each grounding point on the frame is already connected to the other...

[cowcharge]

And the 110 ground should only be a ground for the breaker box case, not the back side of an appliance's power supply like with the 12v lights. There should NOT be any 110 voltage travelling through the trailer frame.

[Bow_Tied]

I agree with Vik.

Cowcharge, I think I know what you mean. 120V appliances should be contiguously grounded back to the main panel via ground wire vs. relying on the chassis as the chassis/frame is not grounded to earth where as the ground in the 120V power supply is.

[cowcharge]

With 12v, you only have two wires, positive and negative (ground). You can attach the grounds from your lights, water pump etc. to the trailer frame wherever it's convenient. My water pump is grounded to the wheel well, so there is only the positive wire that needs to travel all the way through the walls to the pump.

Three wires for 110, hot, neutral and ground, all in the cable. The neutral wire is what completes the 110v circuit back from the appliance. The ground (the round third connector on the plug) connects the frames of outlets, the breaker box, and the trailer frame to earth.