Grounding - Aluminum Frame Trailer

[Rusty99]

Hello,

My trailer has a completely aluminum frame except for the axles. Reading that I should avoid grounding to aluminum as it will likely corrode due to dissimilar metal and eventually will have a faulty ground.

This leaves me with the steel axles and very tip of the tongue/hitch.

My thought was to establish a single common grounding stud where all grounds would terminate.

What should I do? Some pictures would be great.

Thank you,
Rusty

[dmdc411]

Sounds like a great plan! My opinion, with tow lighting, all grounds running to each light using the tow light harness. Shore power, definitely to a point on the trailer, with a ground to each and every outlet. You'll want the trailer frame grounded with the shore power ground for safety. I wouldn't connect the two grounds together, as in 12vdc & 120vac shore power. That could lead to issues. Good luck!

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[tony.latham]

My thought was to establish a single common grounding stud where all grounds would terminate.

Is this for the chassis lights I assume? I would just wire the lighting through a trailer junction box.





Tony

[Rusty99]

Sounds like a great plan! My opinion, with tow lighting, all grounds running to each light using the tow light harness. Shore power, definitely to a point on the trailer, with a ground to each and every outlet. You'll want the trailer frame grounded with the shore power ground for safety. I wouldn't connect the two grounds together, as in 12vdc & 120vac shore power. That could lead to issues. Good luck!

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I am lost where to actually make this single grounding stud, I don't have many options. Any suggestions?

What got me thinking is a video link below (at 4:48 min mark) on the PD4045 mighty mini where the guy says that I should have separate grounding locations for all 3 grounding points on the unit. I can't located 1 grounding point on my aluminum trailer yet alone 3 grounding locations

https://www.youtube.com/watch?v=F8hvTeLcInk&t=339s

[Rusty99]

My thought was to establish a single common grounding stud where all grounds would terminate.

Is this for the chassis lights I assume? I would just wire the lighting through a trailer junction box.





Tony

Hi Tony,

This is for all the grounds in my trailers interior & exterior electrical and mainly my progressive dynamics PD4505 mighty mini.

[Sparksalot]

Use a short piece of #4 aluminum wire attached to the frame and running to an Al/Cu listed ground bar. You can then bring copper wire to the ground bar. The ground bar doesn’t have to be mounted to the frame itself, that should alleviate the dissimilar metal issue.

https://www.homedepot.com/p/Murray-Siem ... B1%7D%3Anf

[John61CT]

Mobile DC does not usually have, nor does it need any true Earth Ground.

Common Reference and Negative Returns yes, and these can connect in multiple places.

It is with AC circuits that things get tricky, important for safety to get it right.

Only one true Earth Ground location at the shore power circuit box, no other.

And once unplugged, rolling or living off grid, floating is the norm just like the DC side. Questions in this topic area with AC should really be put to a pro sparky.

Galvanic corrosion is an even more complex and subtle issue, if you see any signs the sparks at marinas have the gear and the skillz.

[Shadow Catcher]

Ours came from the maker with grounds to the aluminum frame both for DC and AC and I heard the AGM battery boiling when converter was on. It killed the converter and the battery. Fortunately all the circuits had power and ground wire and I pulled all the grounds off the frame. The consequences of a hot frame could have been dire.

[John61CT]

I'm not sure about what was going on with that grounding situation

but it is normal and healthy for FLA batteries to vigorously bubble toward the end of the charge cycle.

Of course verify that the Absorb / CV voltage is being capped within the mfg spec, but for all types the transition to Float should not happen until the CV endAmps point is reached.

More batteries are murdered early by Premature Infloatulation like 98% rather than overcharging 2%.

[foxontherun]

Use a short piece of #4 aluminum wire attached to the frame and running to an Al/Cu listed ground bar. You can then bring copper wire to the ground bar. The ground bar doesn’t have to be mounted to the frame itself, that should alleviate the dissimilar metal issue.

https://www.homedepot.com/p/Murray-Siem ... B1%7D%3Anf

Good afternoon,
Could you accomplish the same thing by just mounting one of these to the frame and use copper wire directly to the frame and eliminate using the aluminum wire? This lug is Al/Cu rated if I read the specs correctly.

https://www.homedepot.com/p/Commercial- ... /310741766

Thanks,
Harry

[Sparksalot]

Use a short piece of #4 aluminum wire attached to the frame and running to an Al/Cu listed ground bar. You can then bring copper wire to the ground bar. The ground bar doesn’t have to be mounted to the frame itself, that should alleviate the dissimilar metal issue.

https://www.homedepot.com/p/Murray-Siem ... B1%7D%3Anf

Good afternoon,
Could you accomplish the same thing by just mounting one of these to the frame and use copper wire directly to the frame and eliminate using the aluminum wire? This lug is Al/Cu rated if I read the specs correctly.

https://www.homedepot.com/p/Commercial- ... /310741766

Thanks,
Harry

That should work well also.

[foxontherun]

Great!! Thanks for the reply!
Harry