Install additional 110 volt outlet in RV

Try RV or Mobile home outlets, they are made for thin walls, and also listed for RV use. Local/small hardware stores (ACE/True Value) usually have some.

I used quite a few of these boxes and they have worked well.

Forget about using a residential type outlet box and receptacle. What you want is a "self-contained device" or SCD for short which are used in RVs and mobile homes. No box is required and can be installed in an existing wall. There is a plastic cover on the back that covers the connections. They are available at any local RV parts store, RV vendors on the internet and on ebay. They are CSA and/or UL approved and are every bit as good as the type used in residential applications. The only trick is "punching down" the wires onto the slotted stabs. There is a proper tool for this but if you are careful, you can use flat-nosed plers or a couple of large flat blade screwdrivers.

RV manufacturers often just screw a standard one-gang cover plate directly onto luan as in the case of TV co-ax/amp outlet at TVs for example (low voltage devices only).

Then just use a double port cover plate only screwed onto the luan plywood beside the receptacle like in the 3rd pic.

Here is a link to an SCD recept. on ebay: SCD receptacle

FWIW, Sigma has a charging center as shown in the last pic. You can also order it with two USB ports.

if you can get behind there you can also use liquid nails or gorilla glue to glue a hunk of wood next to the cutout that you can screw into.

I used this for a charging station

USB

If you have the depth then an old-work JB will easily accommodate even our 1/8" thick luan paneling. The plastic ears clamp down to zero. I've used the ones from Homedepot many times for this.
Link

I wouldn't agree that the RV SCD receptacles are better than a typical residential duplex sold at the big box stores. The SCD receptacles are prone to bad or loosened connections and aren't built with nearly the durability of a standard receptacle.

Also, advocating bad wiring practices (like the elimination of an enclosure) is just not good. There's enough that can go wrong besides trying to use shortcuts.

westend wrote:
I wouldn't agree that the RV SCD receptacles are better than a typical residential duplex sold at the big box stores. The SCD receptacles are prone to bad or loosened connections and aren't built with nearly the durability of a standard receptacle.

Also, advocating bad wiring practices (like the elimination of an enclosure) is just not good. There's enough that can go wrong besides trying to use shortcuts.

Who said something about eliminating an enclosure? Or that they are better? The SCD devices have an integral cover on the rear of them. As an EE, I see absolutely nothing wrong with SCD devices. They are identical to what's used in mobile homes, and there must be millions of those out there without issue. SCD devices, like other electrical devices and components must pass rigorous testing by testing organizations like UL or CSA, the same as residential receptacles. SCD wiring devices are designed and approved for use in RVs - that's what they're for.

The problem with SCD devices, and it does happen at RV plants also, is that the wires can be improperly terminated onto the push-in terminals, either by lack of using the correct tool or by carelessness. There's nothing inherently bad about SCD devices, it's about how they are installed. There's a lot of folks who shouldn't be doing 120 volt wiring in RVs or houses. Even licensed electricians do things like wire up a 120 volt RV for 240 volts. The very first SCD receptacle I pulled out of our first TT did not have the wires properly terminated, with the wires only pushed onto one of the two connectors. With a full 15 amps being drawn through it, it could have possibly overheated.

Like a lot of things, read the instructions, and if you need more help, go on the internet or ask somebody and make sure it's installed correctly.

One major advantage of SCD devices is that they are smaller overall and will fit in shallow cavities. They're also faster to install. There's nothing wrong with installing a residential type outlet box and recept. (or switch) in an RV, as long as it's not in an exterior wall and is installed properly. But doing this just because someone thinks that SCDs are bad is wrong. If there is anything from credible trade organizations, electrical inspectors or electrical manufacturers outlining problems, I'm curious and I'd be interested in seeing links to them.

This photo shows the cover on the rear of an SCD receptacle which covers exposed wiring and parts. I just bought 5 of these to replace white ones in our TT. I just can't see why there'd be an issue with the device itself.

I agree the SCD stuff seems like bad or cheap idea but in reality they work very good. They don't work loose or fail to carry current right up to their ratings. They do fail if someone doesn't know what they're doing and damages them - like forcibly pulling a wire back out.
The same kind of push-blade systems have been successfully used to wire entire commercial buildings, factories and skyscrapers for many years now.

IMO, the SCD device is not as robust as a standard duplex receptacle. The termination is not as secure and they are not built as well.

Myredracer states "RV manufacturers often just screw a standard one-gang cover plate directly onto luan as in the case of TV co-ax/amp outlet at TVs for example (low voltage devices only).
Then just use a double port cover plate only screwed onto the luan plywood beside the receptacle like in the 3rd pic"
This is bad practice and I wouldn't advocate it.

There have been more than a few posts on this Forum of folks trying to find out what the issue is with their 120V receptacles, only to find a loose or burnt wire in their SCD receptacle.

Like ScootG said, I've used old-work plastic boxes in my RV's without issue.