Moving Bathroom 3-arm sconce - Electrical Question

[New Home Owner]

Hello,

A few months ago, we purchased a 3 bedroom, 2 bath 1800 sq. ft.home built in the mid-1960's. We've started to try to update the rooms (stripping wallpaper, painting - nothing major), and this weekend, decided to do the master bathroom. These bathrooms are tiny - maybe

6x5 feet - with tile covering most of the wall like wainscotting. Above the sink was a mirror that we discovered was hiding an in-set medicine cabinet, and a hole where an old wall sconce used to be located. Above the toilet was a new wall sconce, and when I removed it to strip the wallpaper, discovered that there was no junction box, and that it had an extension wire spliced to the old junction box. After much reading, I'm discovering several problems, and want to know if the way I think I can fix it will be an approved repair.

First, the extension wire that was spliced from the original junction box to their light fixture didn't have a ground wire, and the ground wire is just "hanging out" in the junction box. Then, of course, they didn't have a junction box, and the extension wire is 16 gauge (I forgot to look at the circuit breaker to see what amp the circuit is, but I'm betting it is 20). We thought we'd take this opportunity to put a new 3-light sconce up above our medicine cabinet, but of course, we can't use the old junction box because it's hidden behind the medicine cabinet, and the original romex cable coming into the junction box is not long enough to move to a new junction box.

Assuming the circuit is 20 amp, could I get new cable and splice the white/white, black/black, and ground/ground inside the old junction box, and then run the cable the 8 inches up the wall into a new "old work" blue plastic junction box for a light fixture? I'd get a cover for the old junction box, and our medicine cabinet would conceal it so it would still be accessible as per code, but not viewable every day. I'd then follow the lighting fixture guidlines for coupling the white/ white and black/black, but how would I handle the ground? The instructions are to put the fixture's ground wire to the screw, but then what would I do with the ground from the extension cable?

Thanks if you made it through this long question.

[Mike S.]

What you want to do is fine, get rid of that 16 gauge wire, use a piece of #12 romex, 2 conductors with a ground. Connect that in the junction box that will be covered and concealed ( but accessible) behind the cabinet. Then run the new wire inside the wall to the new box you install. Connect white to white, black to black ( I'm assuming USA wiring, other countries are different), and ground to ground and connect the ground to the fixtures ground screw too, in other words all the grounds get connected together to ground the metal of the fixture. I'm assuming all the wires are copper too, if aluminum is involved it is different.

Make sure you do all this with the power off and use approved wire nuts, etc, I'm assuming you have basic electrical wiring knowledge, this isn't rocket science but you do need to have the basics, if not then ask again.

[New Home Owner]

Thanks, Mike.

Yes, I am in the US and using copper wire. Your explanation of handling the grounds helped - I knew I needed to connect them together, but wasn't quite sure if connecting BOTH to the screw in the fixture was the correct thing to do.

[John Grabowski]

In the 1960's it was not required to have a 20 amp circuit for the bathroom. Nor for the kitchen for that matter. The current code does require a 20 amp circuit for the bathroom GFCI outlet and you can leave the lighting on the existing circuit. Since you are redoing the bathroom it is a good idea to bring it up to current standards.

Your plan to redo the light box sounds good. Do what the other poster said with the grounds.

[New Home Owner]

messagenews: [e-mail]...

Mike and John,

We bought the new 12-gauge Romex and hooked up the fixture by the plan and taking your advice about the grounds. The circuits in our house luckily were all brought up to standard some time before we bought the house, so we did have a 20 amp circuit for the bathroom already. Now we just have to repair the giant hole where the old inset medicine cabinet was, and prime and paint. Thanks again!

Layne