Adding a 12v outlet

I think it would be better to simply tie into an existing 12V circuit that seems appropriate.

Yes, but with caution. Remember that you are not connecting to the circuit breakers (which are AC) so more than likely there is no BUS to help you out.

You are connecting to the fuses which typically are powered by a single, heavier gauge wire into the back of the fuse panel.

From the fuse panel you will then have a bunch of smaller fused wires out to the various 12v applications. You should be able to isolate a single 12v wire (I've used overhead lights in my trailer) and tap into that wire for your 12v positive. By going this route you probably do not need a fuse as the wire you tapped into is already fused at the panel.

As far as the negative, you might get lucky and the fuse panel also has a connected ground wire. If no ground wire then you can run a separate ground wire to somewhere. This is where a multimeter to check continuity comes in really handy. It might be possible to tap into the ground BUS on the AC side of the breaker panel. But this is typically advised against. You really want to find a ground location that is a bit isolated from the AC side of the system.

Okay, that makes sense! Thanks for your help and feedback!!

er78mph wrote:
Hello,

I wanted to tie in a 12v outlet at the panel/converter but there is no additional space. The location is really convenient. I was wondering if I can just tap in the the negati e/positive bus behind the panel in order to make this happen? I'll also add an inline fuse. I would just be using the outlet for low watt items. Thanks all in advance!!

Short answer is yes so long as you remember the fuse.

I have extra fuse slots in my panel and have added several additional outlets. Some wired back to the panel (3) some (3 more) tapped into existing circuits that had the current carrying capicity and a proper fuse.

So I found a wire running to a 15Amp fuse at the panel for the "living area" and "exterior lights". Would it be okay to tap into this wire for my 12v connection?, thanks!!

Yes but remember if you turn on too many lights it will be lights out when you plug into that outlet.. Of course if you convert to LED lights... LIkely won't happen. Just so you know each 1141 lamp is about 1.5 amps Running.

Before I tapped into that wire, I would pull its fuse and check to see just what doesn't work anymore. That way you have an idea of how much power that wire is currently supporting and just what will go out if you blow the fuse.

The answers above are the basics electrical circuits and what you can and can’t do.

I believe most auto store or big box store plugs and sockets are rated around 7amps, I chose to use Marinco rated at 15amps.
Marinco socket.
If you use their plugs they are waterproof and have a locking function.


I ran 10 gauge wire from my fuse panel and found an unassigned 20amp spot that I reduced to 10amp fuse. Heated CPAP and handheld car vacuum each have their own outlet.