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So, I had a friend wire my basement for me because even though I had a basic understanding of it, I wasn't 100% comfortable with doing it alone (he's been working construction for several years now). I noticed he wired a string of 8 outlets and then two can lights in the bar. He used 12 gauge wire for all the outlets but 14 gauge for the lights. All this is running on a 20 amp breaker. From what I've read, this is technically not code, but I'm not too concerned with that. I just want to know if it's safe. I also wanted to add an outlet to the circuit for under the bar for a mini fridge, so I'm thinking I need the 20 amp breaker for that reason, otherwise I'd just switch it to a 15 amp breaker. Any thoughts?

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    "this is technically not code, but I'm not too concerned with that. I just want to know if it's safe." - the code isn't just some arcane ritual performer to satisfy some bureaucrat, it's literally a collection of rules that defines a safe system, written out of the blood and ash of people injured or killed in electrical accidents. Take it seriously. Mar 7, 2021 at 18:33
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    Really. Every rule in Code is because a sufficiently large number of accident reports came in to justify the rule. Putting 15A light branches on 20A circuits is one of those things. Mar 7, 2021 at 19:02
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    And by the way, this is precisely why nobody can work on other's houses without a pro license. Your friend has no risk here. You have skin in the game, since you pay the ultimate price for blunders. Mar 7, 2021 at 19:03
  • @Harper-ReinstateMonica I pretty much agree with you, but, and here's the but: In the 2020 code nearly everything in a home has to have GFCI protection....water heaters, furnaces, outdoor HVAC units, Ranges. I believe some of the rules like this are driven by electrical manufacturers who would much rather sell you a $45 breaker than a $4 breaker. I believe GFCI/AFCI protection is warranted for convenience outlets and lighting, but for properly grounded, permanently installed equipment is over-kill. Not only that nuisance trips on freezers and fridges has destroyed a lot of food. Mar 7, 2021 at 21:08
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    @George Industry manipulation is a factor, but there's meat to it. A great many lives would be saved if AFCI were commonplace, so the data supports it. However behind the aggregates is the fact that the casualties are in old housing stock. If the city put down an entitlement rule that "to build this 1000-house development you must kit out 1000 older homes with AFCI"... that would have the intended impact. It would also be "socialism", and we can't have that! Mar 7, 2021 at 22:27

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Not only is it "technically not code", it is not to code and could be dangerous. If you need a 20 amp breaker, then you have to change that wire to 12 AWG. It might be easier to run a new 20 Amp circuit to the bar and change the lighting circuit to a 15 Amp breaker although 8 outlets is a lot for a 15 Amp breaker. This is the kind of stuff that can kill a sale in the future or be a reason to insurance companies to drop you.

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  • Maybe you need the 20A breaker for a dehumidifier or some other basement gadget? You don't need one for a mini fridge so a variation of this answer would be to install a new circuit for the device that needs 20A and use a 15A breaker for the existing circuit.
    – jay613
    Mar 7, 2021 at 19:54
  • Just curious - is there a concept of protecting this extended line with 15 amp breaker right from where it starts (some junction box)? If yes - would it be sufficient?
    – ZakiMa
    Mar 13, 2021 at 1:42
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Giving your friend the benefit of the doubt, he may be misapplying exception 1 of 210.19(A)(4) exception 1a:

Exception No.1: Tap conductors shall have an ampacity
sufficient for the load served. In addition, they shall have an
ampacity of not less than 15 for circuits rated less than
40 amperes and not less than 20 for circuits rated at 40 or
50 amperes and only where these tap conductors supply
any of the following loads:

  (a) Individual lampholders or luminaires (fixtures)
  with taps extending not longer than 450 mm (18 in.) beyond
  any portion of the lampholder or luminaire (fixture).

Basically this means you can use 14 AWG for pigtails for connecting light fixtures, when the light fixture is only rated for 15 amp or less, but those pigtails must be shorter than 18 inches. What your friend did, which was to use 14 AWG from an outlet or switch to the fixture, which almost surely exceeds 18 inches, is not allowed. If that 18 inches is exceeded the full requirements of 210.19(A)(1) must be met:

  1. General. Branch-circuit conductors shall have an ampacity not less than the maximum load to be served.

You should switch to a 15 amp breaker. And tell your friend he needs to review his material before he starts helping on other people's homes.

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By the way, a mini-fridge could use a 6 amp breaker, if we even had that kind of thing in this country. Fridges are very small loads - stick a 'Kill-a-Watt' meter on one sometime.

Our own main fridge consumes 120 VA (1.0 amps) while it is running, and averages 36 watts (0.3A) on a continuous basis. I need just shy of 1.0 KWH per day to keep it going in an outage (which is important to battery sizing). We're talking a golf cart battery per day, more or less.

If you have anything important in that mini-fridge that would be hazardous if it spent time at room temperature, then I would have a dedicated circuit just for the fridge. You don't want a situation where the circuit trips, and later someone resets it because they need a different outlet to be hot, and never realizes the fridge was also on it and everything is full of bacteria now.

That also allows you to put bare minimum circuit protection (AFCI/GFCI) on it, to reduce the chance of a nuisance trip from those. Fridges don't really need GFCI protection, and on a dedicated fridge circuit, AFCI is fairly pointless if the cable is metal-armored.

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In addition to what has already been said, you are also not allowed to install lighting on 20 amp breakers in a dwelling (at least not in Canada, CEC 30-104). Will this start a fire or cause some other danger making this unsafe? I would say no, not in itself...we are talking about an additional 5 amps and to be honest, that 14awg wire could easily handle that, which those lights will never draw anyways. The more likely thing to happen is a short circuit, which the 20 amp breaker will trip just as quickly from. But the reason for the code rule is likely more to do with keeping things conformed to a standard. If you allow this in this particular situation, then it complicates things and can lead to more dangerous wiring habits. Placing restrictions like this helps keep the trade safe, even if it comes at the cost of convenience and is actually unnecessary in a particular instance. The better thing to do is take the lighting off the 20 amp circuit and feed it from another lighting circuit. May require more wiring and work, but it is a better installation and will meet all the code rules. If you overload the circuit causing the breaker to trip, all your lights will still be on so you can see.

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    Fascinating. So where (as I understand it) in the US you could, if you wanted to, wire up all regular receptacles and lighting on 20A circuits with 12 AWG wiring, in Canada you must (as in the US) have some receptacle circuits on 20A but lighting must be 15A. What about bathrooms? AIUI, in the US a bathroom requires a 20A receptacle circuit and that can be shared with multiple bathrooms or with lighting in the same bathroom. In Canada it sounds like you couldn't do that - so lighting would have to be on a separate circuit. Feb 7 at 1:51

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