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PirateKatz 11-24-2008 09:13 AM

Older wiring question...

I have a few questions regarding rewiring the downstairs of an older home. To preface: I live in a 100 year old 2 story, brick, American Foursquare. It has a 100 amp service in a Cutler Hammer panel, which is located in a “modern” (ca. 1970’s addition) w/modern wiring. There is no basement but there is a crawlspace.

The kitchen was remodeled in the late 1970’s and has modern, 3 wire 12/2 NM wiring. Unfortunately, it is attached to the downstairs run of knob-and-tube at one of the receptacles and the microwave and garbage disposal are on the same circuit. The rest of the downstairs receptacles (dining & living rooms) are also on this circuit (15 amp breaker on panel). All of downstairs lights are on a separate circuit.

Ultimately, I would like to hire an electrician to place the kitchen on its own circuit, with the microwave on a separate circuit, and an additional circuit installed for a future dishwasher. I would also like the dining & living room placed on its own circuit too. I’m trying to get a better understanding of what’s involved before I talk to an electrician.

Here are my questions…

1) The knob-and-tube run is visible in the crawl space (2 separate wires, hot and neutral) and I can see where they feed the receptacles, as well as where the cloth NM feeds the “newer” receptacles. Does each knob-and-tube circuit use their own neutral or is there the potential that other circuits would be sharing this same neutral run? How would this be determined?

2) All of the downstairs receptacles are in somewhat small, metal boxes. If I were to upgrade the wiring/receptacles, would it be acceptable to use the existing boxes? They don’t have a grounding screw like new ones do. Ideally, it would be nice to use the old ones because they’re all cut into the original oak baseboards.

3) The breaker box is beginning to fill up. There is an unused double pole, 30 amp breaker that is not being used. Is it possible to replace this with two single pole breakers?


handyman78 11-24-2008 09:26 AM

My shot at your questions:
1) Each circuit SHOULD and likely are using its own neutral per circuit but no one can say with accuracy as we cannot see or test your circuits;
2) Grounding clips (green) may be used in place of screws however you need to be concerned about box fill capacity;
3) Yes, you can replace a double-pole 30a with two single-pole breakers of the same brand as the panel.

Gigs 11-24-2008 09:31 AM

If the knob and tube is visible in the crawlspace, I see no reason why you wouldn't want to just replace it completely. Even if it's installed correctly, the insulation is probably rotting off it, and also the outlets on the knob and tube will never be grounded.

PirateKatz 11-24-2008 10:04 AM

Wow, thanks for the quick replies!

Basically, the goal is to update all of accessible wiring downstairs. The downstairs run of knob-and-tube is visible in the crawl space. Everything "looks" straightforward. In the process of updating the downstairs, I should be able to deactivate and remove the k-and-t fairly easily.

So far, I've determined where the kitchen wiring is tied into the downstairs circuit. It seems like it would be fairly easy to update this. I forgot to mention but the refrigerator and stove wiring was updated fairly recently, so I don't need to worry about this.

The dining and living rooms aren't quite as straightforward but I've been able to map the layout. There is a run of knob-and-tube that runs down the main support beam in the crawl space. It powers one receptacle in the dining room and one in the living room. All of the other receptacles appear to originate at the old receptacle in the living room and run on cloth NM wire. This receptacle currently has me a bit worried, since each terminal has two wires attached directly to it; as it is, I don't think that many pigtails would fit in the existing box.

joed 11-24-2008 10:20 AM

If want to save on your energy bill you need low wattage fixtures. They can be low voltage or normal voltage. You are billed on watts it doesn't matter what the voltage is.

Gary_602z 11-24-2008 05:18 PM

If I understand this right you are running the kitchen and the dining room on 1 15 amp circuit? If so how is your insurance policy?:) Can you run a 12-2 romex(20 amp circuit) for the kitchen and a 14-2 romex for the other 2 rooms (15 amp circuit)? Should be able to run it in place of the knob and tube fairly easy. This would still leave you a extra spot in your box. Ideally you should run at least 2 circuits to the kitchen though.


PirateKatz 11-25-2008 07:24 AM


That's pretty much correct. The kitchen (not including the stove or refrigerator), dining room, and living room are on a single 15 amp circuit.

I know where the kitchen is tied into the existing, older wiring. It seems like it should be relatively easy to put it on its own circuit. There is a built in microwave, which I'm not entirely sure how to fish wires up to but I'm sure it can be done. I'd also like to put in a dedicated circuit for a future dishwasher.

One thing I have wondered... Is there any advantage of using 14/2 and a 15 amp breaker? Isn't it better to just use 12/2 whenever possible just so you can have a 20 amp circuit?

handyman78 11-25-2008 08:29 AM


Originally Posted by PirateKatz (Post 189881)
One thing I have wondered... Is there any advantage of using 14/2 and a 15 amp breaker? Isn't it better to just use 12/2 whenever possible just so you can have a 20 amp circuit?

I like using 14/2 wg & 15a on lighting circuits where there isn't going to be a drastic change of use. In outlets, 20a and 12/2 wg works well for me since you might plug a few high draw items there- vacuum cleaners, window air conditioner, space heater.

Looks like a very good time to seperate out your kitchen circuits now.

theatretch85 11-25-2008 10:11 AM

One thing to keep in mind, if there is ANY 14/2 wire in the circuit it must not be rated for more than 15 amps. So if you do run 12/2 in the hopes of running it on a 20 amp circuit, make sure all the wiring that is connected to it is 12 gauge wire.

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