Switched Wiring

[Thomas K]

Hi! I'm replacing some NM wiring that had no ground with newer NM w/ground. I know that on a simple light circuit power went into ceiling box and you had one length of Romex going to switch box, with black and white wires connecting to switch terminals plus a ground wire. Seems to me I read somewhere that isn't acceptable anymore. Something about the code requiring a neutral wire in the switch box now.

If what I read is correct, you have to run one length of Romex 14-2 w/ground from breaker into switch box, and then another length of Romex from switch box up to light fixture. Thus most of the wiring connections would be made in the switch box now instead of the ceiling box, like it used to be.

There was one other line connected into the ceiling box that goes to one room further over.

If I'm correct about newer way of wiring, could I join breaker box wiring in ceiling box with 1. Line going to other room and 2. Another length of Romex 14-2 with ground going to light switch box? Another length of Romex would come out of that switch box to go back up to the light assembly itself.

Or would I have to run Romex from breaker box directly into switch box, run another length of Romex from switch box to light, and yet another length of Romex from switch box to another junction box in ceiling where it and existing power line to other room would be joined?

Please inform me of the correct way to route wiring. Thanks!

-Thomas

 

[Jadnashua]

If you use 14/3 for at least part of the run, you can have power and neutral sourced either at the ceiling or the switch. The goal is to get a neutral at both locations.

 

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[Thomas K]

I didn't consider that. Using one 14-3 run from ceiling box where power wire is down to switch box would satisfy code requirements, I think. Why the new neutral rule? Smart switches needing a neutral?

Just one question: Would you use the red wire to return power to light instead of white, and connect white wire in switch box to white wire in ceiling box?

By the way, Jadnashua, thanks for the tip!

 

[Jadnashua]

Red is normally used as the switched hot.

You might not need the neutral, depending on the switch, so you could just cap it in the box unless you're daisy chaining power somewhere else.

Some smart switches may need power, so a neutral may be required. SOme dimmers tend to run a small current through the filament of an incandescent bulb, but since most of them today are now LEDs, you don't really want that, so neutral allows the device to be powered without letting a little trickle through the bulb. There are probably other reasons...not sure.

 

[Thomas K]

Sounds good. One thing I may have done wrong is run (2) NM 14-2 light circuit cables along with (1) NM 12-2 cable through a 15/16 hole bored in 2 x 10 joist. 12-2 is dedicated circuit powering 3 bathroom GFCIs.

Is this okay, or do I need to drill some more holes? I have plenty of joist for that.

 

[wwhitney]

The relevant NEC issue is derating due to bundling. That occurs when you have a 24" run of cables without "maintaining spacing" or when you have cables going through a hole that will get sealed (e.g. all holes in a top or bottom plate get firestopping).

So through a single open hole, you can run an arbitrary number of cables without derating. If it's multiple holes in a row, or if the hole is getting sealed, then you have to consider derating. [For runs through open holes in joists, I've thought that someone should make a plastic spreader ring with notches around the perimeter to hold cables apart in each joist bay, to avoid bundling.]

Now, as to derating, it's only potentially a problem if you exceed 9 current carrying conductors (CCCs). With 9 or below, the derated ampacity of the NM cable still exceeds the usual limit of a 15A breaker for #14 or a 20A breaker for #12. For determining CCCs, you don't count the EGC, and a pair of travelers for 3-way switching only counts as 1 CCC. [The neutral of a multiwire branch circuit also does not count.]

Your example is only 6 CCCs, so no problem if derating applies. Which would only be the case if the cables are bundled for 24" or the hole is getting sealed.

Cheers, Wayne

 

[Thomas K]

Thanks, Wayne. Wiring is fed through (7) 2nd floor joists, centered in height of joists. So not sure. But I think on any more runs I'll limit it to 2 cables per hole.

 

[wwhitney]

So that would be bundled, but 9 CCCs is OK. (4) /2 cables or (3) /3 cables are definitely fine.

Cheers, Wayne

 

[Thomas K]

While on the subject of wiring, 20 amp circuit with 12 ga wire that powers up refrigerator is same circuit that feeds (3) outlets above kitchen counters (which are supposed to be GFCI but aren't) and wiring for kitchen range hood. I know I can wire in 1 GFCI and then feed the other two downstream from the LOAD side of the GFCI, so am wondering if this circuit is okay because refrigerator regular 20 amp outlet is wired in upstream of the LINE side of GFCI. I guess I'm asking if a refrigerator, coffee maker, microwave oven, and countertop toaster oven are too much for one circuit.

We have a GE 21 cubic foot freezer, as well, but it will be downstairs in storage room. There were outlets down there, but were wired in with lighting circuit I'm rewiring. This storage room has the breaker box in it, so since I have a couple of legs left in box, I will add a 20 amp breaker and run a 12 ga dedicated circuit for the freezer.

I could wire other outlet into the lights like it was, if I have to. I don't know who did wiring, but they had NM 14 gauge cable with no ground attached to a 20 amp breaker in box. Way too much breaker. The only things powered up by this circuit, as far as I can tell, is the downstairs lighting: (4) 60 watt recessed lights in den (which now have LED bulbs that pull 10 watts each), and four more 60 watt recessed light fixtures in rooms adjoining den. Since you can theoretically have around 1440 watts at your disposal (at 80 percent load) on a 15-amp circuit, I don't think I'd have any problem adding one outlet back to lighting circuit. Reason for so few outlets in freezer room is that all walls are concrete block with 2 x 4 framing around them for drywall.

Update: Remembered that there was one more 60 watt hall light on this light circuit and outdoor flood light with 2 60 watt bulbs in it. Which I am likely to change to LED.

 

[wwhitney]

So you need to have at least (2) 20 amp small appliance branch circuits for the kitchen and dining room. Those circuits have to serve the countertop receptacles and the wall receptacles, and may serve refrigerators and gas ranges, but not hoods. The countertop receptacles can't all be on a single circuit, but otherwise how you divide things is up to you. Other kitchen equipment and lights can be served with other circuits, which can be 15 amps or 20 amps.

Cheers, Wayne

 

[Thomas K]

I didn't know countertop receptacles couldn't all be on same circuit. I haven't done any wiring in kitchen, just checked to see which ones have grounds. Receptacles in kitchen are grounded. Breaker box has three legs left in it, one of which I was going to use for freezer, one other for GFCI outlets (4) in upstairs bathrooms and one downstairs. I think the absolute first thing I need to do is see which lighting and outlet circuits are powered by which breaker, and plan from there.

There can't be that many circuits; this is a 1963 house. One light in each bedroom, none in living room, one in dining room and one in kitchen. Master bath by bedroom on second floor had 2 lights in it, and one power outlet on light. Larger bathroom where I'm putting stackable washer and dryer had 2 vanity light bulbs and one outlet in the switchbox. Breaker spacing for stackables is already accounted for in breaker box. I'll just have to install new dryer outlet and washer outlet (GFCI.) I thought I might have to have AFCI for washer, but Alabama is under NEC 2014, so I think 20 amp GFCI breaker in breaker box will suffice. I would install right behind washer, but couldn't access.

 

[Jadnashua]

When I remodeled my kitchen, I needed to put in a subpanel to handle all of the new circuits and bring things up to code as I was moving all sorts of things around. In 1963, things were pretty lax compared to today's code...but, today, we tend to have LOTS more electrical appliances than we did, and it seems, people aren't all that attuned to some of the safety issues, so we now require GFCI protection and (often) arc fault protection on new circuits.

If you were using something like an electric frying pan, maybe a toaster, or some other heating device, and your refrigerator tried to turn on, you'd probably pop the circuit breaker. In mine now, my frig, dishwasher, stove hood, and lights are all on their own breaker, along with the required two separate circuits for the counter. That all starts to add up. Some like to put a garbage disposal on its own breaker, too, as some of them are a HP or maybe even more, and that's about half the load a 15A breaker can handle, not counting the turn-on surge.

I'd figure out the first counter receptacle in the chain, and insert a GFCI there to protect things downstream from it. You could replace the breaker with a GFCI one, but some would argue about it tripping and your frig defrosting. The latest versions are not prone to false tripping, and it should be fine. You'll hear horror stories about lost goods in the fridge, but generally, today, if it trips, there's a good reason and what's your life worth?

FWIW, I'd seriously consider running a new branch circuit and separating the counter from the frig. You can use 15A receptacles on a 20A circuit, but check the wiring to see what gauge it is, you may only be able to run 14g wire from the panel to the first receptacle unless you want to replace all of it with 12g.

 

[Thomas K]

By subpanel, do you mean a smaller breaker box? I don't think I could fit one next to the main breaker box because it's between a window and a wall. But there is room on the other side of said window. I'm thinking you mean a smaller breaker box that is powered up by (2) 10 gauge wires, but is that ten gauge wire powered by a twin breaker from main breaker box? Reason I'm asking is that main breaker box is almost full, but I'm pretty sure a few breakers could be moved to accomodate subpanel. And I wholeheartedly agree that refrigerator needs a dedicated circuit just like the freezer. But not the freezer's dedicated circuit! I haven't checked to see if the dishwasher is wired in to the outlet circuits, but I'm betting it is.

I've been wiring lights and outlets since I was a teenager, but I will hire a licensed electrician to install the subpanel if needed.

While I'm on the subject of fuse panels, please answer me this: There is an 8-3 cable connected to twin 40 amp breakers in main box, and this cable runs out to another subpanel by AC condenser unit outside. It powers up the HVAC, and also has two other breakers in box. One breaker powers 2 outlets on the pool privacy fence (we're not rich; pool came with the house and is a pain to keep up) and a yard light on a pole. I don't remember breaker size, but I think 20 amp, and outlets aren't GFCI Other breaker powers up the pool pump (110 volts). Shouldn't that pool pump be on its own dedicated circuit? I don't know how many horsepower, but it's a Century Model 0-184981-23.

 

[wwhitney]

By subpanel, do you mean a smaller breaker box? I don't think I could fit one next to the main breaker box because it's between a window and a wall.

Yes. The electrically efficient thing would be to put the subpanel near the kitchen, that way you just run one large cable to the kitchen area (to the subpanel), rather than many small circuits. But that requires an out of the way place for a subpanel, as most people don't want to look at them. Also, the subpanel, like all panels, has to have a clear space in front of it that is 30" wide x 36" deep x 79" tall (not necessarily centered on the panel).

I'm thinking you mean a smaller breaker box that is powered up by (2) 10 gauge wires, but is that ten gauge wire powered by a twin breaker from main breaker box?

It would be rare to use #10/2 (30 amps and 120V), a more common minimum would be #6/3 (55 amps or 60 amps, depending on wiring method, and 120/240V), and larger is common.

Also, "twin" is a synonym for "tandem" which means a two breakers in a single position; they will be on the same leg, so can only supply 120V. A feeder for a 120/240V subpanel would need a double pole breaker which takes two positions and has access to both legs. [Or a quad, which is two double poles in the just two spaces instead of four.]

While I'm on the subject of fuse panels, please answer me this: There is an 8-3 cable connected to twin 40 amp breakers in main box, and this cable runs out to another subpanel by AC condenser unit outside. It powers up the HVAC, and also has two other breakers in box. One breaker powers 2 outlets on the pool privacy fence (we're not rich; pool came with the house and is a pain to keep up) and a yard light on a pole. I don't remember breaker size, but I think 20 amp, and outlets aren't GFCI Other breaker powers up the pool pump (110 volts). Shouldn't that pool pump be on its own dedicated circuit? I don't know how many horsepower, but it's a Century Model 0-184981-23.

Without comment on the other aspects of the installation, the pool pump is on a dedicated circuit. The branch circuit extends from the load to the first upstream breaker. As long as the proper load calculation was done for the 8-3 feeder and it's sized adequately, no problems on that score.

Cheers, Wayne

 

[Thomas K]

There is nowhere in the kitchen I could put it where it would not be seen, except behind the refrigerator and I don't think that would be a good idea. However, the first floor room where I replaced the 4" cast iron plumbing drain pipe is supposed to be a half bath with a sink. What it really is is the old utility area. The water heater sits in one corner, access to crawl space door is there, and there are old washer faucets (disconnected) cemented within the block exterior wall behind toilet someone installed in concrete floor (too close to the wall, I might add).

I could have a subpanel installed somewhere in this room, as it is just below the kitchen area and I think most of the kitchen area wiring enters the crawl space and goes up through the kitchen wall floor plates from below. I will investigate that this weekend. It would likely be about 4-5' away from a small single-sink vanity, though.

 

[wwhitney]

Sorry, no breakers in residential bathrooms (NEC 240.24(E)).

Cheers, Wayne

 

[Thomas K]

Heh! Back to the drawing board!

Just to be curious, is there any code disallowing a water heater in a bathroom? I'm dead serious, because if there is, I can't have a bathroom there.

 

[Reach4]

Heh! Back to the drawing board!

Just to be curious, is there any code disallowing a water heater in a bathroom? I'm dead serious, because if there is, I can't have a bathroom there.

Electric OK. Gas may be ok if the air comes from outside and exhaust goes outside.

 

[Thomas K]

Electric OK. Gas may be ok if the air comes from outside and exhaust goes outside.

It is a newer GE electric water heater.

 

[Thomas K]

Room with breaker box is gutted. I will post a few photos of it here tomorrow evening. I'll also post a few pictures of the kitchen area to see if anyone has any ideas for subpanel placement.