Camper frame grounding bus location

[muttmaster]

I can't seem to find the frame grounding bus on my 2006 Grandby. Per BlueSea Isolator specify I should ground the negative bus bar to the frame on the camper.

I called FWC, and was told to check behind the IOTA for the ground bar, yes there is a ground bus attached to the IOTA right behind the fuses, but I can't trace the wiring to the frame grounding location. I really don't want o tear anymore paneling apart to find exactly where on the frame it is grounded and I really don't want to cut and drill into frame, that is even if I knew where the framing is at.

FWC handout on "Steps to wiring a truck" shows need for metal frame grounding of camper too, but it does not show where the bus is at.

Is the ground bus right below the stock Sure power 1314 that I took out connected to the frame already?

Any help would be appreciated.

 

[ntsqd]

Find an exposed section of the frame and check resistance between the buss that you found and the frame. If its zero or close to it then it matters not where the wire is, you know the frame is connected to the ground buss.

 

[muttmaster]

That is the problem,
I don't see any exposed frame from the inside, and not sure I can or want to drill here and there to find a section of aluminum frame.
If I have seen an open section in the front, I would of grounded in at the spot already. It is all plywood inside in the front.

The ground bus below the battery isolator/separator is just screwed into plywood, not connected to frame.

 

[BFH4N]

I don't know how helpful this will be since it's a different model. On my front-dinette Fleet the DC ground bus is back in behind the IOTA, virtually inaccessible and mounted to the plywood, not the aluminum frame. There is a ground wire running back to a frame connection on the rear wall near the back of the cabinet. At that location, there is a hole (about 1/2") in the plywood interior paneling and a sheet metal screw into the aluminum frame member. There are also AC ground terminals along with AC neutral terminals on a separate block back in there. Again, inaccessible unless you take the front off the cabinet. I don't remember how the AC ground bus was connected to the frame, but it was.

On the outside, metal parts such as the water heater cabinet or the refrigerator grille are screwed into the aluminum frame. You could use one of those screw heads for your ohm-meter test.

- Bernard

 

[Vic Harder]

As Bernard points out, the bus bar behind the Iota is grounded. That IS the "framing ground buss" on your camper. You should be fine to ground, rather than hunting for another separate ground. In fact, keeping everything grounded in ONE place is good practice, as it avoids ground loops, and could potentially reduce the dreaded galvanization/corrosion issue some folks here are fighting.

 

[ntsqd]

Usually the frame is exposed in the door opening where the dead-bolt or latch, or both, engage the striker plate(s).

 

[muttmaster]

Thanks Bernard and Vic, Yes I did find the negative bus behind the IOTA, and I think that bus is wired to the bus below the battery isolator. I still don't know where the bus behind the IOTA is connected to a frame. I guess I shouldn't bother worrying about following diagrams that specify grounding to go the frame. I will do the continuity test Thom suggested. Thanks!

 

[ntsqd]

FWIW I also agree that the fewer grounding points employed the better. If you can make it only one that is good.