Question about CAFCI and an existing breaker...

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Old 05-04-20, 06:08 PM
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Question about CAFCI and an existing breaker...

I purchased a new smart switch for our bedroom and it requires a neutral wire in the light switch box. The way the lights are wired, the power comes into the first lighting fixture and there is no neutral in the box.

The previous owner fancied himself a DIY guy and installed the recessed lights himself. I went up into the attic to see how I could re-route the lines to get a neutral in the light box, I noticed he wired the lights and run to the switch with 14g but the breaker in the panel is a 20 amp breaker. It appears the run to the breaker box was done in 12g wire, however (I need to confirm that, as I didn't look close enough).

Now I am faced with a dilemma. I can run all new 12g wire and keep the 20A breaker or the easier move might be to just switch out the breaker for a 15A one. I am not sure why he used a 20A breaker as the only fixtures on the line are the ceiling fan and then 8 LED recessed lights. I guess for future expansion?

Anyway, if I switch the breaker, I believe the codes have changed and new breakers need to be CAFCI, correct? Or because this 20A line was installed prior to code changes, can I just switch it out for a regular 15A breaker?

Thanks.
 
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Old 05-04-20, 06:22 PM
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I would replace the breaker with a 15 amp.

NEC 210.12 (B) only says if the branch circuit wiring is replaced, modified, or extended you need to install an arc fault. If you are just replacing the breaker then I would not think you are required to install an AFCI breaker.
 
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Old 05-04-20, 06:24 PM
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I agree. I would also add a tag to the wire and on it put 15A only.
This way it won't get changed back to a 20A by mistake.
 
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Old 05-04-20, 08:14 PM
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Immediately after posting this, I decided to dig around some more. It gets a bit weirder, so my apologies if I confuse you guys. Good idea on labeling the line so no one tries to switch in a 20A breaker in the future.

- Let's call the circuit I described as circuit #15. Like I said, it has 14g wire for the fixtures and switch and the run from the breaker box to the first fixture is 12g.

- I pulled off the light switch cover on the switch I want to replace and gave it a better look. Tucked into the back of the box is another line where the hot and neutral are nutted together. I didn't notice this the first time in my quick look in the box. I figured it was maybe a dead line that the previous owner cut off when he reworked the lighting. I killed circuit 15 at the panel to make sure power was off at the box. But when I used a NCV tester, the other line in the back of the box that was nutted together was hot!

- So I went up into the attic, dug around and followed that line to a receptacle. Let's call that circuit 6. So it appears (my guess) that the original light in the room was power by circuit 6 - receptacle was powered from panel and then split to other receptacles and then to power light. Owner just nutted it off in the box (which doesn't seem safe to me) when he ran a new circuit for the recessed lights.

- Now tell me if I am wrong here, but it appears I can now disconnect that line in circuit 6 that runs from the receptacle to the light switch box and use it to rewire the new light switch that requires a neutral line. I would just have to redo the configuration where instead of the power in circuit 15 going from breaker into the recessed light, I could use the existing line in the switch AND the old line from circuit 6 that was nutted off in that box to run power into the box and then to the light, creating the needed neutral connection for the new switch in the box (FWIW, the logistics of where the lines run would make this possible). But then a question arises............. since it would appear I am modifying the circuit, would I then need a CAFCI breaker?
 
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Old 05-05-20, 01:40 AM
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Sorry.... I read this last post several times and can't follow it. I must be too tired.
 
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Old 05-05-20, 04:49 AM
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The black and white spliced together may be part of a switch loop.
 
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Old 05-05-20, 05:56 AM
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Hi, you canít test anything reliably with NCT, agreed that the last post is quite confusing, are you sure the B&W that are spliced together isnít the switchleg going to a fixture?
Geo
 
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Old 05-05-20, 06:48 AM
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LOL, sorry for the confusion.

That wire in the back of the light switch box that is nutted together is a totally different circuit and has nothing to do with the recessed lights on that switch. I followed that line across the attic and it goes down another wall in room where there is a receptable. I have access to the back of that receptacle through the garage attic wall and you can see the line coming in from the panel into that receptacle, then splitting off to power other receptacles in room and run to the switch box in question.

My guess is that that circuit originally powered the old ceiling light but the previous owner disconnected that circuit for the light and ran a new circuit for the fan and recessed lights he installed. But nutting the black and white together of a hot wire off has me bumfuzzled. I must be missing something as my brain is failing to see the potential switch loop, LOL. I am going to pull the receptacle out today or tomorrow and see how it's wired.
 
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Old 05-05-20, 08:40 AM
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Sounds like it may have been a switchleg at one time and the switch was removed and spliced through, not uncommon.
Geo
 
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Old 05-05-20, 08:50 AM
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I probably am just going to disconnect it at the receptacle since it serves no purpose now. I could possibly use then that line to connect to the junction box in the attic so I can rework the configuration in the light switch box to provide a neutral line to connect the smart switch to.
 
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Old 05-05-20, 10:38 AM
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I noticed he wired the lights and run to the switch with 14g but the breaker in the panel is a 20 amp breaker. It appears the run to the breaker box was done in 12g wire, however (I need to confirm that, as I didn't look close enough).
I am not sure why he used a 20A breaker as the only fixtures on the line are the ceiling fan and then 8 LED recessed lights.
That was done and was acceptable by code many years ago.
 
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Old 05-05-20, 10:43 AM
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It sounds like you have a good plan forward.
Owner just nutted it off in the box (which doesn't seem safe to me) when he ran a new circuit for the recessed lights.
FYI, there's no issue with having a live 'unused' cable in a box. As long as it's a box and wire nuts over the end of the wires, it's fine as is.

Of course, if you want to disconnect it completely and cut it out of the box completely, that's fine too... but other than being an odd setup, there's nothing inherently unsafe or code-non-compliant.
 
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Old 05-05-20, 05:41 PM
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I'm not understanding you Joe.

There was what was called a 5' tap rule where you could over size the wire one breaker size up but only based on 5' of wire.
 
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Old 05-06-20, 09:42 AM
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Thanks guys for the responses. After all of this, I guess another option would be to just end up rewiring the lights with 12g and leaving the 20A breaker in. I have enough 12g wire on hand to do it.

Added benefit is that I can spend an hour or so of quiet time away from the kids in the attic. LOL.
 
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Old 05-06-20, 05:25 PM
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I am wondering why the kids are in the attic.
 
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Old 05-06-20, 09:23 PM
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I am wondering why the kids are in the attic.
Isn't that the perfect place to keep them.
 
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Old 05-10-20, 03:21 PM
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I'm not understanding you Joe.
40 to 50 years ago the code allowed switch legs and switch loops on 20 amp lighting circuits to be run with 14-2 NM cable.
 
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Old 05-10-20, 05:15 PM
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Ok. You're showing your age Joe.
 
 

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