My 12v dist. panel has a fused branch circuit that is not used. I would like to add a few small lights from that lead. My question is, what is the proper, safe way to ground it?. ...Hot wire to the switch, then to the lamps. Mounted on wood the lamps need a ground. Where do I connect the ground? I'm thinking a grounding bus for 12v in the converter, but I can't find it.To clarify, I have an 06 Cougar 5er. The converter is a WFCO 8955. I want to install small lights in a large dark pantry. My converter has a neutral bus and a grounding bus on the A C side. I don't think I want to ground 12v to the 120 A C side of the box. I think Burbman had it right. I will check behind the converter when I get home.Seems like a common converter, so I will post what I find. Thanks everyone

all 12vdc circuits in the RVhave 2 wiresboth the positive and the negativerv house circuits, do NOT use the frame grounding method that Vehicles useinsde the converter you will find a NEGATIVE busit will NOT be grounded to the RV frameyes the battery is, but the 12v circuits are wired with 2 wires from the converter/fuse panelits possible you will find all the Negatives, fastened/connected together inside or behind the converter

MrWizard wrote:all 12vdc circuits in the RVhave 2 wiresboth the positive and the negativerv house circuits, do NOT use the frame grounding method that Vehicles useinsde the converter you will find a NEGATIVE busit will NOT be grounded to the RV frameyes the battery is, but the 12v circuits are wired with 2 wires from the converter/fuse panelits possible you will find all the Negatives, fastened/connected together inside or behind the converterSomewhere that NEGATIVE is fasten/hooked to the battery, most likely through the frame, or none of the 12 volt would work.Dusty

Most of the negative wires in the house are returned to the power distribution box (the box that contains the power distribution panel), however my converter is grounded to the frame.I can't think of any electrical reason for this, and so I think the negatives are returned to the power distribution box because there is no metal frame in the house, all plastic and wood.

All of the above...Yes, there is a negative bus in the converter, but it connects to the frame and uses that as the path of (-) on the battery. So there is nothing wrong with grounding to the frame IF you can fine frame to ground to...in a stick/tin or fiberglas RV the frame only runs around the bottom...Depends on where you are planning to install the lights. If inside then plan on running a 2-wire set from the converter so you have a return path for ground. If for example you were adding a light under the RV for the steps, you could could ground right to the frame.

My 12v ground bus for accessories is behind the converter panel.

grounding new 12v branch circuit | Good Sam Community

westend
Explorer
Oct 01, 2013
Two wires to your new light fixtures. One power wire to the vacant distribution panel position and one wire to either DC (-) ground bus, the battery, or the frame.

I don't like having a bunch of frame grounds spread across the frame. I'd rather pull more wire and use busses. I have two wires to the frame, an AC ground to the load center and a DC ground to a buss.
MrWizard
Moderator
Oct 01, 2013
the POINT BEING
he HAS TO RUN a negative wire from the new lamp to somewhere, like a negative buss or maybe the Frame
not just attach it to the metal skin or the closes 'Aluminum' strut
Bobbo
Explorer II
Oct 01, 2013
I get tickled.

In a thread about the 12v system, it is asserted that you CAN NOT connect the 120v system's ground wire to the frame.

In a thread about the skin of the RV shocking you, the answer is to ground the frame to the 120v system's ground wire, then to the power source's ground path.

Come on guys. Ground is ground is ground, on every system. While purists will say 12v doesn't have a ground wire, the 12v negative wire is electrically identical so I will use the terms interchangeably. Note, that does not include the 120v neutral.

If you crawl under my MH, you will find literally dozens of 12v ground wires bolted to the MH frame in each of 4 or 5 areas, and the 120v ground wire going from the breaker box to the frame. They did not carry each and every 12v ground wire back to the distribution system. Also, the negative (ground) wire from the battery goes only to the frame. The negative (ground) 12v wire from the converter goes only to the frame.

Also, both the chassis and house batteries are connected to the frame, so the grounds of both 12v systems are connected. The only thing that separates those 2 systems is the isolator/relay that separates their hot wires. Otherwise, the relay to connect them together would have to be double pole to connect both the hot wire AND the ground wire.

To the OP, you can carry the ground for your lights anywhere you want that connects back to the battery. That includes the RV frame, as well as the distribution system's ground buss. The only thing I would not do is use a ground wire from the 120v system, but that is for esthetic and trouble shooting purposes. Electrically, it would work just fine.
haddy1
Explorer
Oct 01, 2013
RoyB,

Your schematic appears to be correct. The top note on the right hand side explains how the DC SHOULD be wired.
MEXICOWANDERER
Explorer
Sep 30, 2013
"Lo siento mucho pero no hablo Ingles". Like eating in a Vietnamese restaurant, if you were present during the making, you would flee. These guys have gunfights over saving a nickel. Someone in a suit shows up at the front door, the staff shimmies out office windows. Someone in a uniform shows up and all the noise in the assembly area stops, dead. All you can hear is the rapid patter of sneakers.
BurbMan
Explorer II
Sep 30, 2013
How I understood it too.
OnaQuest
Explorer
Sep 30, 2013
Running dedicated (+) and (-) wires from source, through load and back to a ground bus, will certainly add a degree of reliability and problem solving flexibility, but EVERY RV I have ever worked on (there have been many dozen) have had the AC an DC systems BOTH ultimately GROUNDED to the vehicle frame.

Just for clarification and simplification, the ac neutral and ground should NEVER be bonded (connected together) in an RV. The ac GROUND should always be connected to the frame ground, but the ac neutral should NEVER be.
MEXICOWANDERER
Explorer
Sep 30, 2013
Tolya I was dumb. Image says for me to go do something immoral to myself if I try and copy it.
BurbMan
Explorer II
Sep 30, 2013
MEXICOWANDERER wrote:
I am too computer dumb to know how to copy and paste the image but here is a link to a small buss. The hole with no screw is the one you run a screw down into the wood to hold it with.

http://www.homedepot.com/p/Square-D-by-Schneider-Electric-3-Terminal-Ground-Bar-Kit-PK3GTA1CP/202353311#.UknhIj8cTPs

Just like in the pic I posted above
RoyB
Explorer II
Sep 30, 2013
Here is a schematic of my DC setup using the WFCO series 89 power distribution center.

I have a DC negative bus bar which is also grounded to frame ground.

My DC cable is a 2-conductor 14GA or 12GA BOAT WIRE that has the BLACK and WHITE color conductors in it. One of these is run to each DC device. The BLACK lead connects to a fuse position in the panel and the WHITE wire goes to the DC NEGATIVE ground bus.

Roy Ken