12V wiring Aluminum Cargo Trailer conversion

djglover7 wrote:
I was responding to *your* post.

Thanks for the clarity, sorry for my poor re-read (dummy me - lol), I was only running on 7 dang cylinders...

I was responding to *your* post.

djglover7 wrote:
Thank you 3tons.

"I would note that AFAIK, within the main, household copper wire is commonly attached to aluminum lugs harboring steel screws...".

That appears to be true for the neutral bus bar.
The ground buss bar is steel/steel.

Are we talking metallurgical compatibility, conductivity, or maybe something else - I’m somehow missing your point?... I’m of the ‘KISS’ persuasion - I’ve often seen aluminum wire and copper wire and steel components co-mingled within the same Main...BTW, your aluminum chassis is a far better conductor than steel, yet steel is commonly employed as an effective ground return in all vehicles...You’ll be fine so long asyou apply a small dose of De-Ox...

Thank you 3tons.

"I would note that AFAIK, within the main, household copper wire is commonly attached to aluminum lugs harboring steel screws...".

That appears to be true for the neutral bus bar.
The ground buss bar is steel/steel.

I would note that AFAIK, within the main, household copper wire is commonly attached to aluminum lugs harboring steel screws...

djglover7 wrote:
All,
My one unresolved issue is:

*IF* I bond/connect 12VDC negative to chassis *AND 120VAC ground to chassis, is there *ANY* issue with voltage surges/spikes/daemons going from AC to DC?

The big concern is surges/spikes/daemons going from AC to the tow vehicle (DC).

Please advise.

Answer: No, this is common accepted practice...

All,

I have added a ground link (10AWG) from the AC ground bus to the chassis.

But, before I made the connection, I wanted to test whether or not the 12VDC positive would close the circuit to chassis ground. My assumption was NO as I have not seen any AC grounds to the chassis.

(Note: this is a DIY toy hauler that I purchased and I inherited all the undocumented work.)

When I did the test with a simple 12VDC circuit tester, I showed a complete circuit (i.e. light came on). So, somewhere, one of the receptacles is grounded or one of the appliances is grounded to chassis. (I also assume that if a bare grounding were to touch the chassis, no issue).

I think I am safe now and I can continue with locating the mystery grounding points.

Yes, the 120v and 12v share the same RV frame for ground (120)/neg (12). Typical RV power centre has the 120v incoming to the 30a Main breaker with the bare ground wire going to the RV frame. Meanwhile the converter in that power centre uses the same RV frame for much of its several neg paths to the various 12v items such as slide motor, jacks, etc. The metal skin of RVs that have that is the negative path for the clearance lights too.

The metal casing of the power centre is grounded to the frame as is the "lower portion" 's metal casing (chassis) so that is the "chassis ground" for the converter. If you have a deck mount converter it will have its own chassis ground from a lug on its metal casing. Same with a bigger inverter.

Warning--do not bring the chassis ground of an inverter back around to its own neg input terminal. That does get to the frame via the battery's neg ground to frame, but you are supposed to run the inverter chassis ground direct to the frame.

Those inverter chassis grounds are to reduce radio interference.