Questionable wiring

[kf4zht]

Tracing down breakers to label them in my house and ran across some questionable wiring. Is this legit?

Circuit panel has a 14-3 cable running in. Ground and neutral are normal. Black goes to one 15a breaker, red to another non-connected 15a breaker.

Run to a switch box. One hot then runs right back out to an outlet where the AC condensation pump is connected, and a mini fridge. Other hot goes to a light switch then out to the blower motor/controller on the furnace. All neutrals are tied and all grounds are tied.

So what is confusing me:

Can you have 2 "separate" 110V circuits that share a neutral of the same size? Seems to me you would then possibly be putting 30a over that line

Why does my furnace blower have a light switch on it? Is this a cheap way for a disconnect? Not a big fan of it since it is right next to the stairs where someone could accidentally hit it trying to find the lights.

 

[goldie lox]

yes, that can be done and is common practice. it saves money having to run 2 wires to the same area. EXCEPT IT HAS TO BE DONE RIGHT IN THE PANEL. you have two phases in the panel, they are 180° apart meaning that they are opposite of each other allowing you to share the same neutral. JUST MAKE SURE, AGAIN, JUST MAKE SURE that they are opposite of each other when they are hooked to the breakers. that means if you count down the breakers on one side in the panel from top to bottom like 1,2,1,2,1,2,1,2,1,2 ect make sure that one of the wires are on 1 and the other is on a 2. it sounds confusing but really its not. usually when its done like this they are installed red on one breaker then breaker right below is the black. if the two hots are on the same phase, or number, you can over load the neutral and melt it if there is to much of an imbalance. this is the where you asked about a 30a breaker. hooking it up right it will have 15a on all there wires. hooking it up wrong you could have 15a on the two hots and 30a on the neutral. if this is two confusing message me and i can talk to you. MOST IMPORTANT OF ALL. NEVER NEVER NEVER oversize breaker for the wire. if you do this, take a look inside of you toaster when its working. see the little wires get red hot. thats what your wires inside your walls will be doing if you put to big a breaker for the wire in. one last thing, when you're counting the breakers count the double pole breakers as 2 single breakers. so a double pole breaker would be 1,2 or 2,1 depending on where is it installed.

 

[goldie lox]

forgot about the switch part. yes, the switch is a normal thing. new installs usually have this mounted right on the side of the furnace

 

[Orionrising]

yes the breaker need to be next to eachother and tied together so you don't end up with it half hot and half not

 

[G_P]

yes the breaker need to be next to eachother and tied together so you don't end up with it half hot and half not

He's not running a 240v circuit. he has 2 seperate 120v circuits sharing a neutral wire. One circuit to run a pump and a fridge and one to run a blower motor.

I dont know if its code legal, but I would not have wired it that way. I would have run 2 separate circuits. One for the outlet powering the pump/fridge and one to run the furnace blower.

 

[pattenp]

Or the breaker needs to be a common trip double pole breaker. Untied single pole breakers are not to be used on a multiwire branch circuit (MWBC).

read this... http://ecmweb.com/code-basics/branch-circuits-part-1




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[goldie lox]

He's not running a 240v circuit. he has 2 seperate 120v circuits sharing a neutral wire. One circuit to run a pump and a fridge and one to run a blower motor.

I dont know if its code legal, but I would not have wired it that way. I would have run 2 separate circuits. One for the outlet powering the pump/fridge and one to run the furnace blower.

so with this thinking, whenever there is a three phase wiring, you would run each phase alone with its own neutral? no. you dont do it this way. the phases are out of cycle enough to allow for sharing of the neutral. when done with single phase wiring a 220v is also sharing the same neutral. this it the same as running two sperate 110v. you are sharing the same neutral. in either situation you are only getting one phase of the cycle on the neutral at one time. the only thing to remember when sharing a neutral is to keep on hots on opposing phases.

 

[goldie lox]

Or the breaker needs to be a common trip double pole breaker. Untied single pole breakers are not to be used on a multiwire branch circuit (MWBC).

read this... http://ecmweb.com/code-basics/branch-circuits-part-1




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mwbc? that is for ungrounded circuits. not for his 14/3 wiring he is using.

call your local inspector. i deal with them on a daily basis

 

[pattenp]

mwbc? that is for ungrounded circuits. not for his 14/3 wiring he is using.

call your local inspector. i deal with them on a daily basis

Ungrounded circuits, what are you talking about? A multiwire branch circuit is where you have 2 circuits using one cable such as a 14/3 where the neutral is shared. This is exactly what the OP has.

Edit: The reference says ungrounded conductors, not circuit. Ungrounded conductors is the terminology for the hots.


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[goldie lox]

Ungrounded circuits, what are you talking about? A multiwire branch circuit is where you have 2 circuits using one cable such as a 14/3 where the neutral is shared. This is exactly what the OP has.

Edit: The reference says ungrounded conductors, not circuit. Ungrounded conductors is the terminology for the hots.


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A multiwire branch circuit basically consists of two or more ungrounded conductors that share a neutral. All conductors of a multiwire branch circuit must originate from the same panelboard [210.4(A)].

For personnel safety, each multiwire branch circuit must have a means to simultaneously disconnect all ungrounded conductors at its origin [210.4(B)]. If that origin is two or more breakers, you can provide this disconnect by using single-pole circuit breakers with handle ties identified for the purpose [240.15(B)(1)].

 

[pattenp]

A multiwire branch circuit basically consists of two or more ungrounded conductors that share a neutral. All conductors of a multiwire branch circuit must originate from the same panelboard [210.4(A)].

For personnel safety, each multiwire branch circuit must have a means to simultaneously disconnect all ungrounded conductors at its origin [210.4(B)]. If that origin is two or more breakers, you can provide this disconnect by using single-pole circuit breakers with handle ties identified for the purpose [240.15(B)(1)].

I know the code, so what's your point? That's where I said you need to use a DP breaker if not using SP breakers with handle ties.

 

[goldie lox]

Ungrounded circuits, what are you talking about? A multiwire branch circuit is where you have 2 circuits using one cable such as a 14/3 where the neutral is shared. This is exactly what the OP has.

Edit: The reference says ungrounded conductors, not circuit. Ungrounded conductors is the terminology for the hots.


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and with your thinking every 3phase panel has to have the breakers your talking about because they share the same neutral?

 

[pattenp]

and with your thinking every 3phase panel has to have the breakers your talking about because they share the same neutral?

Who said anything about 3 phase?

Edit: Are we not talking about 14/3 cable serving as 2 circuits from a single phase panel? From my training and experience that's a multiwire branch circuit.


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[teamextreme]

OP has a MWBC. Goldie's advise was all correct, but now you're running into the weeds arguing about MWBC. That is exactly what the OP has and the setup does need to be phased properly as both Patten and Goldie pointed out. Years ago it was legal to hook up the 2 hots on a MWBC to 2 separate breakers. Now it is required to have them on a 2 pole breaker, or at least handle tied 1 poles. Not sure what you're trying to say regarding 3 phase. Yes, same applies to 3 phase. If you have 2 hots (or 3) sharing a neutral, the breakers need to be tied together.

 

[kf4zht]

Didn't realize I was going to start a big discussion with this. I verified that the breakers are on different phases, but it sounds like if I keep it adding a breaker tie would be wise. I am also looking at moving the switch for the AC to one that mounts on the side of the cabinet or get a cover so it won't be mistaken for a light switch.

Saving wire is a pretty lame excuse here. The AC is 5 feet from the breaker panel. It might have saved 10ft of wire.

 

[APEowner]

Regarding the light switch for the furnace; some municipalities require a switch like that at the top of the stairs when the furnace is in the basement. The idea is that you don't have to go into a smoke, fume, fire filled basement to shut the unit off if it malfunctions. Yes, they do get shut off accidentally on occasion.

 

[sberry]

Old code had different requirements. I believe some handle tie was in a newer version.

 

[NY_treeguy]

My house (Built ca 1942) had most circuits run this way, but with 12 ga BX. One cable was run to the kitchen attic, then it was split into 2 runs, each with a separate neutral from that junction box. I guess they were short on copper during the war. It has since been changed with the red wires capped at both ends.

 

[Mustang51js]

A multiwire branch circuit basically consists of two or more ungrounded conductors that share a neutral. All conductors of a multiwire branch circuit must originate from the same panelboard [210.4(A)].

For personnel safety, each multiwire branch circuit must have a means to simultaneously disconnect all ungrounded conductors at its origin [210.4(B)]. If that origin is two or more breakers, you can provide this disconnect by using single-pole circuit breakers with handle ties identified for the purpose [240.15(B)(1)].

What year code book are you reading from, you used to be able to use two separate single pole breakers but now you have to use a two pole breaker so you don't back feed the neutral if you disconnect the wires. Another thing to protect people who shouldn't be working on electric. As far as the switch at top of stairs it is code for oil furnace to have a switch at top of basement stairs. You may still have oil or has been swapped out over the years but the switch was left. The multi branch circuit is normal and still used today,just not as much thanks to the arc fault breakers now required. It's just more money for homeowners to have to pay out in materials and extra labor of running wires

 

[zmaxmotorsports]

Id say it depends on when it was installed as to whether or not its a violation.

 

[kf4zht]

The switch is not at the top of the stairs, it is at the bottom, right next to the unit and near all the switches for the basement (other than the stairway light)

The house was built around 2002-2003, AC appears to be from the same era. It seems that the AC company did all the wiring, not the electrician. None of the AC breakers were labeled and the wire sheathing is slightly different than anything else in the house.

If the lazy installers had labeled the breakers and the switch I never would have noticed. Sounds like it may have been code but it's a pretty cheap way to save 10ft of already inexpensive wire.

Now the next mystery is how a 3 bedroom 2 bath house is completely filling a 42 spot panel. (only 6 are for shop/garage stuff including the entire basement). As soon as the replacement wire hound gets here I have my work cut out

 

[Mustang51js]

Sounds like someone went overboard,prob have two circuits per room,one for lights and one for outlets,out side outlets prob separate circuits too.

 

[APEowner]

The switch is not at the top of the stairs, it is at the bottom, right next to the unit and near all the switches for the basement (other than the stairway light)

Well, I have no explanation for that!

 

[urbanG33K]

This has been a very informative thread. Thanks to OP for asking the questions and thanks to those who provided clear answers.

 

[urbanG33K]

Now the next mystery is how a 3 bedroom 2 bath house is completely filling a 42 spot panel. (only 6 are for shop/garage stuff including the entire basement). As soon as the replacement wire hound gets here I have my work cut out

I have this same problem myself right now. My panel is full, Im in a 3 bedroom / 1.5 bath bungalow built in mid 90's and my panel is full.

The kitchen, has 4 double throw breakers (including the stove), plus 2 separate untied singles. Just insanity in my opinion.

 

[Mustang51js]

Kitchens need the most circuits, at a minimum you have 2 counter,micro,dishwasher,refrigerator,and lighting. So that's 7 right there, throw in an electric oven and garbage disposal and your up to 10,any other wall outlets would need to be a different circuit also if it's not on the counter.

 

[urbanG33K]

Kitchens need the most circuits, at a minimum you have 2 counter,micro,dishwasher,refrigerator,and lighting. So that's 7 right there, throw in an electric oven and garbage disposal and your up to 10,any other wall outlets would need to be a different circuit also if it's not on the counter.

Oh yeah, the dishwasher, forgot about that. That's another double breaker I forgot to mention. Microwave is running off the counter plugs (which we have 4 of). No garberator/disposal


I miss counted...

4 counter plugs, each on it's own double.
Stove - another double
dishwasher - double
2 lights, range hood and fridge and 110v floor outlet behind stove on a single
3 more outlets at floor - patio door and kitchen table on another single

so that's 14 positions in my panel. I guess when you look at it in terms of code requirements I get it. It's just easy to point fingers at the biggest culprit( kitchen) when your cursing your full panel. I ended up running a small sub panel that was already mounted to the board beside my main panel, but wasn't hooked up, when I took possession of my house. I guess the previous owners had the same idea, but didn't really know where to start in terms of wiring it up.

 

[nafterclifen]

Why are ya'll complaining about a full panel? So what. I say that's better than having too much space. It might have cost a bit more but more than likely, you shouldn't have to worry about overload. And...when you need to shut off a breaker to do any electrical work, you're more than likely only affecting a small area as opposed to disconnecting power to a larger area that is fed off of only one breaker. I'm wiring seven 4' fluorescent fixtures to one 15a breaker. Overkill? I don't think so. Benefit to me is that I'll be able to keep the lights on in the garage even when I shut off all of the breakers feeding power to the garage.

 

[ishiboo]

Well, I have no explanation for that!

The NEC does not require a switch "at the top of the stairs", and I am guessing you can count the number of municipalities with the rule you suggested on one hand. Or no hands.

The NEC DOES require a disconnect in sight of the furnace, which almost always means a single pole toggle switch on or near the furnace, as that's the cheapest way to do it.

 

[urbanG33K]

Why are ya'll complaining about a full panel? So what. I say that's better than having too much space. It might have cost a bit more but more than likely, you shouldn't have to worry about overload. And...when you need to shut off a breaker to do any electrical work, you're more than likely only affecting a small area as opposed to disconnecting power to a larger area that is fed off of only one breaker. I'm wiring seven 4' fluorescent fixtures to one 15a breaker. Overkill? I don't think so. Benefit to me is that I'll be able to keep the lights on in the garage even when I shut off all of the breakers feeding power to the garage.

True.

It becomes a bother though when you want to add just 1 or 2 circuits and every position on your 100amp x 48 breaker panel is in use on a 1250 sq foot bungalow with an unfinished basement. Again, just seems excessive the way 'they' wired my house specifically.

No matter - I have a sub panel for my needs now so I'm all good.

 

[katy]

"Regarding the light switch for the furnace; some municipalities require a switch like that at the top of the stairs when the furnace is in the basement. The idea is that you don't have to go into a smoke, fume, fire filled basement to shut the unit off if it malfunctions. Yes, they do get shut off accidentally."

Ditto

Put a #4 strap over the switch so people have to stop and think before they turn it off.

Don't know if they still make them, but years ago you could buy a red colored switch plate with the words "Furnace shut off" (or similar) on them, to use in those applications.