In my 1929 house, I have a half bath off my master bedroom. The house has new 200 amp service with a new breaker panel feeding about 2/3 of the circuits. The rest of the circuits are fed from a fuse panel.

The master bedroom light/fan, outlets, and master bath light is all fed from one circuit in the fuse box. (currently has a 30 amp fuse on the hot and one on the neutral).

I have ripped out the walls in the bathroom to repair water damage while I have the walls open, would like to add a switch for the light and a GFI outlet. There is currently just one line running straight to the pull-chain lighting fixture.

The wiring in the light's junction box is beginning to fray a bit, but behind the wall it looks like it's in great condition. I'm not sure what 'type' the wiring is, but it's two conductors, no ground; inner wires are wrapped with a braided paper-looking insulator. The outside insulation is black. Outter insulation diameter is probably a good half inch.

I belive I've read somewhere that a GFI outlet cannot be on the same circuit as lighting fixtures. Is this the case? I guess that probably means I need to run a new circuit back to the breaker box? I have another bathroom on the same floor, not far away that needs outlets too. Can I add a GFI outlet to that bathroom on the same circuit?

As for the light in the bathroom and adding a switch, should I run a new circuit for it while I'm running one for the GFI, or continue to use the existing wiring? The bedroom has one ceiling fan w/ 3 lights, and has 4 other duplex outlets, which will probably feed two bedside lights and one chairside reading lamp.

Thanks in advance for the info.

 

First of all, unless the old wiring in question is 10 guage, you need to drop that 30AMP fuse to a 20AMP fuse (if its 12 guage wire) or a 15AMP fuse (if its 14 guage wire). Sounds like the circuit was blowing fuses so someone "upgraded" to a 30AMP fuse, creating a fire hazard.

For the bath outlets...
Current code requires that bathroom *outlets* be on their own circuit, and that the circuit be GFCI protected. (Even though its a 1929 house, any new wiring must adhere to todays code).

You can run one new circuit to one of the bathrooms, then go from that bath to the second bath. If you do that, the lights must be on a different circuit. You can provide GFCI protection in three ways: 1. Standard 20AMP breaker and GFCI outlet in each bathroom, 2. standard 20AMP breaker, GFCI outlet in the first bath, and a standard outlet in the second bath fed off the *LOAD* side of the GFCI, or, 3. GFCI breaker and standard outlets in the baths.

Option 1 is the best option, IMO, as a ground fault only kills power to the outlet where the ground fault occurs whereas as the other two options leave both baths without power if a ground fault occurs.


For the light...
I'd go ahead and run a new circuit there while I'm at it since you have the walls tore up anyway. Running two circuits shouldn't be much harder than running one.

You *may* be able to also use this circuit to replace a few more outlets/lights on that old circuit since it was apparently overloaded (the 30amp fuse). Just don't tie any of the old wiring into the new. Only problem with doing this is if you feed any of the master bedroom from this circuit, you will have to AFCI (ie, arc fault) protect this circuit with an AFCI breaker per current code (bedroom recepticles must be AFCI protected by todays code). The code gurus here can give more details, and correct any errors in my advise. (Code gurus please answer this: Can the AFCI circuit for a bedroom also serve the master bath lighting?)

 

Numerous problems are evident from your post. In addition to the hazards that chirkware cited, you also mentioned a fused neutral. That sounds really bad.

To address one of your specific questions, there may or may not be a code problem with putting lighting on a GFCI bathroom receptacle circuit. We have too little information to tell. There's no blanket prohibition, but it might be prohibited for other reasons.

To address chirkware's question, yes it's okay to put bathroom lighting on a bedroom AFCI circuit.

There are literally hundreds of electrical codes which apply to this project. It would be difficult to list them here. But let me say that bathrooms and kitchens are highly regulated by the electrical code, and anything you do without studying the codes first is very like to violate many of them.

I recommend you pick up the $6 green paperback Wiring Simplified in the electrical aisle of Home Depot. Read every word in it.