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Posted: 5/3/2022 7:54:57 AM EDT
[#1]
It probably has been working that way for years
Change bulbs ?? to led , amps will go down |
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Posted: 5/3/2022 7:59:51 AM EDT
[#2]
Quoted: I saw this set up in a barn in a property I was looking at and am curious about it. 12 /2 wire runs from a 20 amp breaker in a subpanel. It feeds a 3 switch gangbox, each switch controls a seperate circuit of lights. The light circuits are 14/2 wire. I calculate about six amps per circuit (5 150 watt lights each). My questions- I know that 14 wire is usually limited to a 15 amp breaker, is that the case here? If all the circuits are on together, I assume the 18 amps would would trip a 15 amp breaker. Is this set up ok with a 20 ? Thanks. No. Lighting circuits are considered continuous duty, and for that you have to derate the circuit ampacity to 80%. So a 20a circuit x .8 is only rated for 16 amps, and a 15 amp breaker would only be rated for a 12 amp lighting load max. I know years ago we were allowed to mix/match circuit/switch legs in residential IE. 20a circuit with 14/2 switch legs, but I believe now you would have to limit the breaker size to 15 amps if 14/2 is used anywhere along the circuit. I don't think its as much of an overload issue as much as it is an equipment ground size/resistance issue. |
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Posted: 5/3/2022 8:05:10 AM EDT
[#3]
I am not an electrician but…
Whether something will “work” is a different question from whether it meets “code”. The total load on the 20A circuit breaker sounds like it may be “OK”, subject to limitations of “code” which may not be as “OK”, but the individual branches would be “happier” if each branch were protected by its own breaker. |
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Posted: 5/3/2022 8:45:48 AM EDT
[#4]
Quote HistoryQuoted: No. Lighting circuits are considered continuous duty, and for that you have to derate the circuit ampacity to 80%. So a 20a circuit x .8 is only rated for 16 amps, and a 15 amp breaker would only be rated for a 12 amp lighting load max. I know years ago we were allowed to mix/match circuit/switch legs in residential IE. 20a circuit with 14/2 switch legs, but I believe now you would have to limit the breaker size to 15 amps if 14/2 is used anywhere along the circuit. I don't think its as much of an overload issue as much as it is an equipment ground size/resistance issue. ^^^^ Technically correct. |
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Posted: 5/3/2022 9:06:04 AM EDT
[#5]
I'm not an electrician but.....
Circuit breakers are there to protect the wires, not the bulbs, not the vacuum cleaner, not the toaster, etc. It's the wires that are more likely to burn the house down when overloaded. 14/2 is good for 15 amps, not 20 amps. I would put in a 15 amp breaker and LED bulbs. |
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Posted: 5/3/2022 9:50:33 AM EDT
[#6]
Quote HistoryQuoted: No. Lighting circuits are considered continuous duty, and for that you have to derate the circuit ampacity to 80%. So a 20a circuit x .8 is only rated for 16 amps, and a 15 amp breaker would only be rated for a 12 amp lighting load max. I know years ago we were allowed to mix/match circuit/switch legs in residential IE. 20a circuit with 14/2 switch legs, but I believe now you would have to limit the breaker size to 15 amps if 14/2 is used anywhere along the circuit. I don't think its as much of an overload issue as much as it is an equipment ground size/resistance issue. Especially at my house where they never turn anything off. Our next house is not going to have any switches, all the lights will just stay on 24x7. My Bedroom will just have a clapper wired in. I'd think our circuit powering our TVs, the Fans and a few other things should be rated continuous duty as well. I mean unless I turn them off, they do not get turned off. Every morning before work I turn off Our Bedroom TV and Fan Bathroom 1's light Step Daughter's Room light and Fan, TV and anything else she happens to find an interest in and turns on. Living room TV, fan and air purifier Kitchen Lights and ceiling fans Bathroom 2's lights. If I say anything, I'm an unreasonable asshole. They've commented that I leave my PC and laptop on (which go into sleep mode after 20 mins), so I guess that justifies leave everything in the house on. |
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Posted: 5/3/2022 2:15:22 PM EDT
[#7]
Quote HistoryQuoted: I've never heard that before, but it makes plenty of sense. Especially at my house where they never turn anything off. Our next house is not going to have any switches, all the lights will just stay on 24x7. My Bedroom will just have a clapper wired in. I'd think our circuit powering our TVs, the Fans and a few other things should be rated continuous duty as well. I mean unless I turn them off, they do not get turned off. Every morning before work I turn off Our Bedroom TV and Fan Bathroom 1's light Step Daughter's Room light and Fan, TV and anything else she happens to find an interest in and turns on. Living room TV, fan and air purifier Kitchen Lights and ceiling fans Bathroom 2's lights. If I say anything, I'm an unreasonable asshole. They've commented that I leave my PC and laptop on (which go into sleep mode after 20 mins), so I guess that justifies leave everything in the house on. You too, huh? 
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Posted: 5/4/2022 3:03:37 PM EDT
[#8]
#12 wire is good on a 20A breaker
#14 wire is good on a 15A breaker You are not supposed to mix wire sizes...breakers need to match the smallest wire size in a branch circuit As another person mentioned, the breaker is protecting the wire, not lights or whatever you plug in. |
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Posted: 5/4/2022 9:30:41 PM EDT
[#9]
I would sub panel the barn with 15 Amp breakers to protect the 14 Ga wiring
What worries me most is the size of the feeder to the building and apparently no ground rod there. You really need a 4 wire feed from the house feed to the outlaying building plus a local ground rod. Switch to LED bulbs helps. |
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Posted: 5/4/2022 10:51:02 PM EDT
[#10]
Quote HistoryQuoted: Our next house is not going to have any switches, all the lights will just stay on 24x7. My Bedroom will just have a clapper wired in. I know you jest but light switches (location and number) are required by code, I don't think a clapper meets code (but occupancy sensors do). |
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Posted: 5/5/2022 12:43:14 PM EDT
[#11]
Thanks for the help. I'm still trying to learn about this type of stuff. So if I put a 15 amp breaker on each 14 line as it exits the switch Box, it would be OK because each branch only carries its own load so the individual 15 amp breakers would not trip? Is this correct?
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Posted: 5/5/2022 6:45:46 PM EDT
[#12]
Quote HistoryQuoted: Thanks for the help. I'm still trying to learn about this type of stuff. So if I put a 15 amp breaker on each 14 line as it exits the switch Box, it would be OK because each branch only carries its own load so the individual 15 amp breakers would not trip? Is this correct? Breaker in the panel yes.. Don't wire in a breaker right after the switch, that would be weird |
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Posted: 5/5/2022 7:55:33 PM EDT
[#13]
Quote HistoryQuoted: Breaker in the panel yes.. Don't wire in a breaker right after the switch, that would be weird Got it, thats what I am thinking, run input into a panel, then a breaker for each branch. |
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Posted: 5/5/2022 9:22:12 PM EDT
[#14]
Quote HistoryQuoted: Got it, thats what I am thinking, run input into a panel, then a breaker for each branch. The easy solution was already proposed. Change all the lights to high efficiency lights (LED) then switch the 20A breaker to a 15A to protect the #14 wire. If the lights are already high efficiency there are other options that may work. |
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Posted: 5/5/2022 9:39:14 PM EDT
[#15]
If box was with a 12 on 20 A breaker, I would not worry much. Each light switch feeds lights with 14 wire, no load on each individual switch and the 14 wire will be anything to worry about.
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Posted: 5/6/2022 1:21:45 AM EDT
[#16]
Quote HistoryQuoted: If box was with a 12 on 20 A breaker, I would not worry much. Each light switch feeds lights with 14 wire, no load on each individual switch and the 14 wire will be anything to worry about. Smarter people then me on the subject but here is my 2 pennies If your only concern is overload then I could see not really worrying much about the OP's situation on a lighting load that is basically fixed. But.... If there is a fault a real worry is getting the upstream OPD to function properly and in a timely manner. Time is key and the 14ga wires WILL impact. MAX overcurrent on 14Ga is 15 amps See NEC 240.4(D) |
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Posted: 5/6/2022 7:26:43 AM EDT
[#17]
Quote HistoryQuoted: The easy solution was already proposed. Change all the lights to high efficiency lights (LED) then switch the 20A breaker to a 15A to protect the #14 wire. If the lights are already high efficiency there are other options that may work. I should have been more clear, lights are already LEd ufo type, theres one outlet the 12 wire feeds before the lights, hence trying to see how to keep the original 20 breaker. Thanks again to all for the answers |
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Posted: 5/6/2022 9:10:58 PM EDT
[#18]
Quote HistoryQuoted: I should have been more clear, lights are already LEd ufo type, theres one outlet the 12 wire feeds before the lights, hence trying to see how to keep the original 20 breaker. Thanks again to all for the answers In that case there is no code compliant way I can think of w/o spending a lot of money & time or replacing the 14 ga wire. It is technically a code violation. But if you look at this question on electrician forums there is a lot of debate about the topic. Most agree it is a code violation, though many argue that it's not actually that dangerous. There is so much factor of safety built in to the breaker size vs wire size equation that many argue a 20A would likely trip before a 14 ga started a fire, especially if the outlet or the other light switches were on as well. |
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Posted: 5/6/2022 9:51:49 PM EDT
[#19]
Quote HistoryQuoted: I should have been more clear, lights are already LEd ufo type, theres one outlet the 12 wire feeds before the lights, hence trying to see how to keep the original 20 breaker. Thanks again to all for the answers As a rule of thumb you load a breaker max 80% of its rated current for a continuous load. A 15A breaker that would be 12A - 20A breaker would be 16A If your wanting to do it properly you could run an additional circuit to the lighting box divide the load appropriately and breaker both branch circuits at 15A Before I did anything I'd clamp it and see where you are actually at |
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