14g wiring on 20amp circuit

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Old 01-01-21, 03:59 PM
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14g wiring on 20amp circuit

The wiring to my bathroom is on a 20amp breaker, with a 12g wiring running into the bathroom from the breaker. The 12g wire from the breaker terminates in a 3 gang box that contains 3 switches. From there it pigtails to a mix of 14g and 12g wiring. The one 12g wire runs to a single gang receptacle box a few inches away. The rest are 14g gauge wires running to the 3 switches in the box which control the shower fan+light, a night light in the shower fan, and the vanity lighting above the sink. Is this to code?

I know it's very bad to run 14g wiring on a 20amp breaker to a receptacle because someone could plug appliances into both outlets and draw up to 20amps before tripping the breaker, which is unsafe on 14g wiring. However for the light and fan, the loads are fixed and known, and never more than probably 2amps. I guess the risk would be some malfunction in the fan or lighting that somehow caused it to draw between 15 and 20amps. I'm not sure if this is a realistic concern, and I'm not sure if code requires 12g wiring in this application for this reason or some other.

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Old 01-01-21, 04:01 PM
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20 amp breaker means 12 ga wire. Period.
 
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Old 01-01-21, 04:05 PM
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All the wiring is required to be #12 (or larger) to be on a 20 amp breaker. If there is #14 in the circuit then you may only use a 15 amp breaker.

Note: Fixture wires are covered elsewhere in the code. Fixture wires are only the wires that come with the fixture from the manufacturer.
 
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Old 01-01-21, 05:13 PM
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Ok. I guess I need to downgrade to a 15amp breaker then, at least for now. It's been this way for a couple years now since a contractor renovated the bathroom. I was planning on having him do some more work in the next year or so. I'll talk to him about it then to see how hard it will be to upgrade the wiring. Unfortunately I'm pretty sure the wiring to the vanity light will require putting some holes in the walls. The fan will be easier since it runs straight up to the attic where it is exposed.

BTW, are there any potential code issues with downgrading the breaker to 15amp? The breaker services this hallway bath, the outlet in the hallway, and the small bedroom across from the bathroom (ceiling light and outlets). Might there be something in the code that says this is too much for a 15amp breaker?
 
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Old 01-01-21, 05:44 PM
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The only violation would be that bathroom receptacles are required to be a dedicated 20 amp circuit. Having the circuit properly protected is more important at this point.

It might be easier to run a separate 14/2 circuit to the switch box and put the lights, fan, and other bedroom on that circuit and just run the 12 gauge wiring to the receptacle. Then your wiring would be correct.
 
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Old 01-01-21, 06:16 PM
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With all the areas outside the bathroom on the same circuit it sounds like you house was built well before the code requirements for the 20 amp circuit.
 
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Old 01-01-21, 06:32 PM
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Yes, it was built in 1976.

So the bathroom receptacles need to be on their own 20 amp circuit. Ok, so let's say I run 14/2 on a new 15 amp breaker to service fan and lights. That still doesn't isolate the receptacles since they currently are on the same circuit as the hallway receptacle and the bedroom. So it sounds like I need to also run a 12/2 for the bathroom receptacles and a new 20 amp breaker for it.

I'm assuming here that a bathroom remodel requires that all wiring in the bathroom be brought up to code, even if it was in code before the remodel. In other words, the remodel itself necessitated the need to put the bathroom receptacles on their own 20 amp circuit (and this is a completely separate issue from the 14/2 running to the lights and fan).

[Slight correction. I see now that the suggestion is have the 14/2 also service the bedroom, so probably can still get away with just two circuits].
 
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Old 01-01-21, 06:37 PM
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If you want to do it the the right way the outlets need to be on a dedicated 20AMP and gfci protected either at the receptacle or the panel. The vanity light may be on a separate 15 AMP shared from another room (does not have to be dedicated circuit). The fan / light combo really should be on a dedicated 20 also depending on the draw. The most important thing to do at this point would be to replace the breaker with a 15 AMP breaker and make sure your receptacles are GFCI protected. I would be leery about having the same contractor that put substandard wire on a 20 AMP circuit come back and do more work.
 
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Old 01-01-21, 06:49 PM
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Receptacles are GFCI protected. Not sure about your concern with the fan/light combo and putting it too on a dedicated 20 amp circuit. I don't think it even draws 1 amp.

Yes, I understand the concern about the contractor. I'll need to talk with him. He is friendly and honest. He does use subcontractors, and I know he will subcontract larger electrical jobs. But for this job he did things like plumbing and wiring himself. Possibly he just saw this as a smaller job that felt he could tackle himself to keep costs down, but he is not as knowledgeable of electrical code as he should be.

I also plan on having any future renovations permitted, which would catch issues like this. I (naively) didn't for this job. It was the first time I hired someone for renovation work, and I just didn't understand the importance of permitting (contractors around here never seem to encourage permitting) when you ask.
 
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Old 01-01-21, 06:55 PM
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The exhaust fan light can share a lighting circuit.

A 20 amp circuit can serve lighting and fans as well as 5he receptacle if the circuit only serves one bathroom.
 
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Old 01-01-21, 07:04 PM
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A 20 amp circuit can serve lighting and fans as well as the receptacle if the circuit only serves one bathroom.
That doesn't really help much. It means the 14g wire to the fan and lights still needs to be replaced with 12g, and I still need a new circuit to service the hallway receptacle and the bedroom. So it looks like 2 new circuits is an easier approach as it avoids (I think) punching holes in the wall, which leads to another question. When running conduit from the attic straight down to the electrical box, does it need to be secured to a stud? If yes, I guess there would still need to be some hole punching, although not as much as when replacing the 14g wiring.
 
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Old 01-02-21, 04:40 AM
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No hole punching or enlarging is needed for the sole purpose of securing wires to a stud. Omit the securirng at those points where you thought you would punch or enlarge a hole. (You would secure the wires at the first and last already open locations beyond the enclosed space to come as close as possible to meeting the distance between securements.)

You will need at least one new branch circuit, either a new 20 amp circuit to become the required bathroom circuit, or to re-energize other wires and #14 wires orphaned by being removed from the existing 12 gauge circuit that becomes the bathroom circuit.

Nothing forbids a second bathroom receptacle with existing feed from another branch circuit although all bathroom receptacles need ground fault circuit interrupter protection.
 
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Old 01-02-21, 03:51 PM
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Allan, there are a couple of things in your post that I'm not so sure what you are trying to say, mostly regarding the "dedicated bathroom circuit", so let me just state my current understanding of things:

The bathroom needs a dedicated 20 amp branch circuit for at least the receptacles, but it can also include the bathroom lighting and fan. This circuit cannot service anything outside of the bathroom. The receptacles in the bathroom cannot be on a circuit that services anything outside the bathroom, but the lights and fan can be on a circuit that provides service outside the bathroom.

So given this, the simplest solution seems to be to replace the existing 20 amp breaker with a 15 amp, and provide a new 20 amp circuit that services just the receptacles. Yes, it could also service the lights and fans, but that would require upgrading the wiring to 12g (the receptacles are already using 12g but the lights and fan use 14g from the switch). The bathroom lights and fan, the hallway receptacle, and bedroom light and receptacles can share the 15 amp circuit.

Does this sound right?
 
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Old 01-02-21, 04:19 PM
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Yes what you said is right.

I believe that there are some additional combinations (not encountered here) that will work:
(3) A 20 amp circuit serviing bathroom receptacles only (no lights, etc) can be the bathroom circuit for two or more bathrooms. This is not preferred because two persons using hair dryers may trip the breaker.
(4) An additional receptacle in the bathroom, for example wired on a different circuit with the lights in a medicine cabinet, does not have to be separated and put on the bathroom circuit.
 
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Old 01-03-21, 05:22 PM
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Any fan/light bathroom fixture I wire I put on a dedicated 20. Many times the homeowner decides they want a heater also and this way I don't need to try to run a new circuit. I also do all my GFCI protection at the panel with combo breakers to also meet the newer code and also have AFCI protection.
 
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Old 01-03-21, 07:06 PM
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Yeah, I'm thinking of getting my panel replaced and upgraded to AFCI and AFCI/GFCI combo breakers. It's 44 years old and has seen better days. Will probably have it done as part of the kitchen remodel when that eventually happens.
 
 

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