Isolating Existing circuit

[vdotmatrix]

Moving onto the next home project.

I am putting in a new bathroom exhaust/light/heat unit and I was required to pull a permit for the electrical to run NEW 20A circuits to the existing bathroom.

The house was built in 1956 and it had a 100amp panel before I replaced it with a 200A one years ago.

HERE IS WHERE IT GETS COMPLICATED FOR ME:
The existing circuit supplies the back bedroom, hallway, bathroom and my daughter's bedroom with a series of 3-wire and 2-wire cable to the switches, fixtures and outlets (ahhhhhhhhh!); there are no 3-way switches.

I want to take the bathroom off this circuit and here is the question:

Because of the 2-wire , 3-wire dance it's doing can I just remove the switching branches and wire nut all the blacks together, and so on and still maintain the circuit for the rest of this circuit to the other bedrooms? They are all still neutral and black and grounds right-uh, on the same circuit?

[HayZee518]

Uh, you said it above - NEW DEDICATED CIRCUIT(S) TO THE EXISTING BATHROOM" Answer run two new circuits to the bathroom. The heater will take probably all the 20 can provide and the fan/lite the other circuit. the fan is a fractional horsepower type, I have a fan/light/heater "with fan" and night light combination here. I ran two 20 amp circuits to this gizmo off a common trip two pole breaker.

[pushkins]

Around here inspectors want to see a dedicated circuit for bathrooms, by dedicated I don't just mean the obvious dedicated breaker, they also want to see a "stand alone cable run" from panel to bathroom.

[vdotmatrix]

Yes thankyou!

I also said, or tried to say, that I needed to do something with the existing circuit.

Is wire nutting the blacks, whites, reds and grounds a fail safe method for isolating the bathroom from the existing circuit (i.e. by-passing the bathroom), if I don't know from what direction the wires come from and otherwise don't know what to do with the series of 2-wire and 3-wire combinations on this circuit???

The new circuit details are already addressed in my approved electrical permit, and only serve as background for clarity in my rambling question to the group!

(I hope to have big enough boxes to accommodate the old wiring and the new wiring or else I'll have to have a box with a blank plate which will look really ugly. (wire limits inside boxes-always something ).

[vdotmatrix]

Around here inspectors want to see a dedicated circuit for bathrooms, by dedicated I don't just mean the obvious dedicated breaker, they also want to see a "stand alone cable run" from panel to bathroom.

Pretty much around here too and of course adhering to the 2008 NEC.

I am pulling 2-20A 12/2's with respective breakers as detailed in my permit as required for the dedicated heater circuit on the unit and the other for the bathroom 20A CFGI outlet and vanity light. Thanks

[HayZee518]

OK, you're gonna need to find how many feeders are going to your switchboxes and outlets in all the rooms you speak of. Since you say there are no three way switches but there is a few three wire lines we're gonna hafta look for a switch leg for split wired outlets in the bedroom(s) Chances are that the outlets in the hallway are just two wire. bedroom one and bedroom two have split wired outlets part of which is switched, the other half hot at all times. bathroom will have a two wire to a gfci and downstream loads will be taken off the bottom screws of the gfci. tell me what you have in each switchbox and I might be able to tell you what to splice together. look in the codebook for"box fill" requirements. this is the number of 12 wires you can legally put into what size box. each gangeable box has a certain number of cubic inch volumns of wires you can put in there. a typical 2x3x2 1/2 inch box can take only two 12 wires plus receptacle and be in compliance.

[vdotmatrix]

I am psyched that you know exactly what I am talking about....

I will collect all the diagrams I made as I opened up each box and post them. I had an idea i was going to need this when I started seeing 3-wire stuff.

All I am concerned with are the switch legs to the existing fan/heat in the bathroom and I 've identified them. I see the same kind of phenom. at the existing vanity light where the 3-wire and 2-wire interact (wire pigtails) and then one or the other continues to the next fixture in the next room....which of course i am not concerned with.....Once i understand the wiring pattern, I will see how the 2 and 3 wire interacts in the existing bathroom wall switch box,and then can isolate that circuit!

I am lucky on this project because it seems like the wiring travels across the floor in the attic and I have open access to it. So, I won't have to worry about correct box size and volume for max. numbers of conductors per box and I can pull the wires up or cut them and make splices in a j-box up in the ceiling and be done with that but first have to ensure circuit continuity......

Once all this noise is addressed, I can finish pulling the NEW 12/2's for this circuit!

Thanks for your time!





!!!!! Yippeee!

[vdotmatrix]

Here are the diagrams .

Essentially there is a 14/2 circuit that runs along the house to the hall lite j-box. From there a 3-wire heads off i think to the hall light switch (this has a 2-wire and 3-wire in and out, see diagram). the bathroom switch box controls a single vanity light, ceiling heat lamp and fan as wellas has a single 110v outlet. (see diagram) Next it looks like 3-wire heads off to the vanity light box from the bathroom switch box. In there I see the 3-wire, a 2-wire and another 2-wire....this all heads to the adjacent room to power an over head light, and 2 wall outlets where I do believe this circuit terminates....

[HayZee518]

I redrew your diagram so I could better understand it. You've got a feeder for the hall, which extends to a bedroom, then goes to the bathroom vanity lamp round box, then comes out of there and goes to the other bedroom. Since you have access from the attic, I'll suggest you put a four inch square box near the vicinity of the wall partition between the bedroom and bath vanity lamp and feed the 14/2 that comes from the hallway ceiling box to the square box. Then hopefully you'll have enough of slack to bring the two wires you have coming out of the vanity lite box to the square box. You'll be eliminating the existing line from the hallway to the vanity lite box. I don't think you'll have the length to use the existing line. The hallway light switch stays the same. the new two wire splices onto the feeder from the panelbox. the new wire from the hallway box to the square box splices onto the two wire going to the outlets in the other bedroom and the switch loop black goes to the feed black with a black taped white going to the ceiling lamp of THAT bedroom. This will completely isolate all the boxes and fixtures in the bathroom. If I got you right more will follow.
All the 14 in the bathroom will have to come out as you are going to use two dedicated 20 amp circuits for the bathroom if I understood you.

[vdotmatrix]

wow! yes to the very last question. I don't need any of those.

I saw example(s) of this style of wiring in BLACK and DECKER's complete Guide to HOME WIRING 2001, the 2-wire/3-wire runs.

Do they still wire houses this way today? to save wire by sharing, WHAT?, the neutral wire right?

Once I can isolate this circuit I can blast though the rest of the project! Thanks for taking the time!

It is fun for you figuring out this stuff for folks right!!! I know I appreciate having a place like this to share my experiences and to learn from the more experienced giants in this field...thanks again! v.

[vdotmatrix]

hmmm, i think from the hall lite box the 3-wire to goes to the hall lite switch (this box has the 3-wire and a 2-wire in and out) instead of directly to the vanity box?.

I can see the bathroom box and vice versa from the hall lite switch box (since they are adjacent inside the same wall almost touching inside the wall) so I think the cabling goes to the bathroom box next, instead of the vanity box which appears to be further down the line and up high on the wall.

Remember, the bathroom switches also have a SINGLE 110 outlet in that box so it has juice. (2-prong, no GFCI). hope this doesn't confuse the picture more.

[HayZee518]

from what you are telling me what I see is a two wire from the panel to the hallway light box. then a three wire from that box to a wall switch box and then a two wire to the bedroom OR bathroom. the feeder is in the hall lite box. the whites are spliced here. the black of the two wire and the three wire are spliced. the red goes to the hall light [black fixture wire] at the wall switchbox the white of the out going two wire is spliced to the three wire white. [this carries the neutral on through] the three wire black and the two wire black plus a black pigtail are spliced. the pigtail goes to a switch terminal and the red goes to the other switch terminal. this turns on-off the hall light. the two wire coming out of this box goes where? bedroom or bath?

[HayZee518]

ok, then, the two wire out of the hall switchbox goes to the almost back to back bathroom box. so you got a hot in here. this wire you'll want to remove out of this box and run it into the attic to a square junction box. this will be your continuous feed to the other bedroom, and isolate the bathroom. [for your dedicated 20 amp - 12 wire]

[vdotmatrix]

Great! so it is the 2-wire is the key for this kind of wiring scheme. You called the continuous feed.

Inthe Bathroom switch BOX: The 2-wire that supplys the outlet only contributes the white (nuetral wire), The black comes from the 3-wire from the light switch.

[HayZee518]

NO! the white and black supply power to the bathroom. you got yahoo messenger?