Adding DC circuits on my Interstate

[StephensNC]

I am adding a couple of new circuits to my 2014 Interstate for charging my phones and iPad and other 12 equipment. I'm confused by the DC side of the load center as there are no individual negatives from the various existing circuits attached to the negative bar. For my new circuits, do I bring my negative sides directly to the vertical bus bar where the large white jumper is attached?

[wiseguy2315]

You should not have to add any grounding at the distribution panel. The distribution panel has only 1 DC ground that all the circuits pass through. As far as adding the circuits are concerned, this is what I would do to determine if you can add them:

1. Throw on all your DC load.
2. Use an amp meter to determine how much current is passing through the ground wire with all your DC loads on.
3. Run the new circuits you want to run on the floor and plug in the devices you want to be able to charge. As far as grounding is concerned, try tapping into nearby DC grounds. Make sure that the ratings of ground wires you're tapping into can handle the additional amperage (if you're able to add the circuits permanently, I would break them up among your remaining circuits in the distribution panel. Laptops can use as much as 10A to charge, so you may run into a problem with that. However, iPads and smartphones only use a couple of amps).
4. Remeasure the current in the ground wire in the distribution panel. If you have room to spare within the rating of the ground wire in the distribution panel, you can add the circuits permanently. If you don't, do NOT add the circuits permanently.
5. Consult RVIA for the proper gauging of wires that correspond with different max amperages (i.e. 15A = 14Ga, 20A = 12Ga, 30A = 12Ga).

The distribution panel I believe has a max amperage of 30A for the first 2 circuits and 20A for the remaining circuits, but consult the manual on the distribution panel for verification.

If following the above steps yields that you cannot add the circuits and your unit has 12V accessory sockets, I would use those. If your unit does not have those, I would use a wall adapter on an inverter circuit while dry camping.

[StephensNC]

Thanks, wiseguy2315, for the explanation. It was very helpful. I was only adding two small, short circuits for USB connections at the back near the lounge. I ended up running both the loads and the grounds into the load center but could easily could have tapped the white common for the two grounds. I ended up adding a jumper from the white common over to the otherwise unused ground bar for the DC section and attached the two negatives at that point. Either way it works great now that i understand it better.

[wiseguy2315]

No problem. Just make sure that any work you do, you consult the RVIA standards.

[Boxster1971]

Originally Posted by wiseguy2315

No problem. Just make sure that any work you do, you consult the RVIA standards.

If one desires to consults the RVIA standards this link has entire list.

https://www.rvia.org/standards-regul...ansi-standards

You have to pay for all these standards. However those published by NFPA are available to view for free at this link.

https://www.nfpa.org/codes-and-stand...-and-standards

It would be great if all standards organizations would offer their documents for free viewing like NFPA. The free viewer only allows you read, but not copy or download the entire documents. But it is still useful.

This article by Mike Sokol, a well know RV electrical Safety professional is worth reading.

https://www.rvtravel.com/rv-electric...find-out-here/

[Rocinante]

Given the quality of the wiring I've seen installed by technicians who were allegedly following RVIA standards, I wouldn't worry too much about that specific question. I'd focus more on ensuring a good, safe electrical upgrade that follows proper DC wiring practices.