Grounding Question

[DunnYet]

Adding a 12 volt run to the nightstand, and looking at the grounding bus bar which appears to be full. Previous owner had an accessory added and doubled up a ground, which my understanding is a no-no. I could swear that I had seen a discussion of grounding on the Oliver in the past, but searching “grounding” “ground bus” and “ground bar” didn’t get me anywhere.

While familiarizing myself with the back of the 12 volt fuse panel, I found what looks to be a completely unused ground bar. It appears to head out through a floor penetration in the outer hull, I assume to a grounding point on the frame. Is there a reason this is unused? If I am connecting to a new fuse point for this 15 amp run to the nightstand would this be a valid place to connect.

And yet - I am removing the accessory that the previous owner placed 🙂 It was a “Smart Hub” and I have the TPMS switched to the built in Ford and we use a different temp monitoring system. So that “no-no” will be going away.

[jd1923]

23 minutes ago, DunnYet said:

doubled up a ground, which my understanding is a no-no.

This is not true. You can certainly double-up grounds. I would double up the lighter gauge yellow wires, 2 per screw-down which can give you many available spaces in the negative bus. I did this on ours after adding a new longer negative bus.

I'm not familiar with your 12VDC fuse panel pictured. Our much older hull has 12VDC fuses and 120VAC breakers integrated in one combined panel. To see if this is grounded correctly, use the continuity setting on a multi-meter. Touch this negative bus with one probe and touch the main negative bus (with all the yellow wires) with the other probe. If you hear the alert sound for continuity then this bus is properly connected to the battery negative post and can be used for any negative 12V wire.

If the unused bus is not grounded (connected to B- in a 12V system), you can ground it by running a 6 or 8 AWG wire to connect the two negative buses. I would not count on a frame ground in a trailer or RV electrical system. All 12V negative wiring must terminate at negative battery terminal. In an automotive system, the negative battery terminal is grounded to the steel frame.

Positive +12V wires can be wired to positive buses connected to the battery + terminal. Negative -12V wires (some use the word "ground" but "negative" is correct) can be wired to positive buses connected to the battery - terminal.

[DunnYet]

Thanks @jd1923 - I have not taken a look in the LE I from ‘22 to see what it has. In the ‘23 they used two different panels - one for DC and one for AC. Will take a photo tomorrow morning of the front and post. Appreciate the grounding tips - will run that test in the morning as well. Rebecca wants me to finish up the wiring projects so she can get the beds back together.

[jd1923]

46 minutes ago, DunnYet said:

Rebecca wants me to finish up the wiring projects so she can get the beds back together.

Love this sentiment, Chris too! That's why I did this extensive work. It keeps me from going under the beds unless I'm working a new mod! 🤣