#14 switchlegs on a 20A light circuit

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102 Inspector

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N/E Indiana
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There used to be a practice to run switch legs for lighting on 14 ga even though the circuit was 20 amp overcurrent device. Is this an acceptable practice still? I have not seen anyone do this for a long time in my jurisdiction and wondering if I am missing something. Do not want to reject something that is acceptable. Thank you.
 
Daniel malack

Daniel malack

Senior Member
Location
Amissville, Virginia USA
102 Inspector said:
There used to be a practice to run switch legs for lighting on 14 ga even though the circuit was 20 amp overcurrent device. Is this an acceptable practice still? I have not seen anyone do this for a long time in my jurisdiction and wondering if I am missing something. Do not want to reject something that is acceptable. Thank you.
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20 amp means 20 amp! Use 20 amp wire............ period!

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kwired

kwired

Electron manager
Location
NE Nebraska
Something that was done a lot in some places, think it would have been a very long time ago if it ever actually was NEC acceptable, like possibly back when knob and tube wiring was still the main wiring method being used.
 
Fulthrotl

Fulthrotl

~Autocorrect is My Worst Enema.~
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102 Inspector said:
There used to be a practice to run switch legs for lighting on 14 ga even though the circuit was 20 amp overcurrent device. Is this an acceptable practice still? I have not seen anyone do this for a long time in my jurisdiction and wondering if I am missing something. Do not want to reject something that is acceptable. Thank you.
Click to expand...

the premise would have been that the connected load would normally
have been a couple hundred watts, and you'd never overload a #14
wire.

not code compliant. never has been, to my knowledge.
 
Daniel malack

Daniel malack

Senior Member
Location
Amissville, Virginia USA
kwired said:
Something that was done a lot in some places, think it would have been a very long time ago if it ever actually was NEC acceptable, like possibly back when knob and tube wiring was still the main wiring method being used.
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You must use correct wire size to breaker not load. I worked with people who focused on load more than Supply. It's the breaker size that determines the wire size. Within its context.

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102 Inspector

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N/E Indiana
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Inspector- All facets
At least I know I am not completely crazy. I seem to remember a few old timers doing this in the late 80's, but had not seen it for a long time. It is a shame that contractor now has to replace 500 feet of wiring just because of switch leg reduction of conductor sizing. I know the argument will be that it is LED lighting with minimal load, but as stated, it is the supply that dictates the conductor sizing, not the loading. thanks for the quick responses.
 
don_resqcapt19

don_resqcapt19

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102 Inspector said:
At least I know I am not completely crazy. I seem to remember a few old timers doing this in the late 80's, but had not seen it for a long time. It is a shame that contractor now has to replace 500 feet of wiring just because of switch leg reduction of conductor sizing. I know the argument will be that it is LED lighting with minimal load, but as stated, it is the supply that dictates the conductor sizing, not the loading. thanks for the quick responses.
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Why would the wire and not the OCPD be replaced?
 
J

Jim1959

Senior Member
Location
Longmont, CO
TABLE 210.24 TAPS

TABLE 210.24 TAPS

There are allowable branch circuit taps per Table 210.24. Maybe the OP had learned from those who utilize these taps, whether code compliant or not. I've worked with electricians who believed they could tap circuits for an individual receptacle or light fixture without distance limitations. Per 210.19(A)(4) Exception #1, the uses for these taps is quite limited.
 
Daniel malack

Daniel malack

Senior Member
Location
Amissville, Virginia USA
102 Inspector said:
At least I know I am not completely crazy. I seem to remember a few old timers doing this in the late 80's, but had not seen it for a long time. It is a shame that contractor now has to replace 500 feet of wiring just because of switch leg reduction of conductor sizing. I know the argument will be that it is LED lighting with minimal load, but as stated, it is the supply that dictates the conductor sizing, not the loading. thanks for the quick responses.
Click to expand...
Just change the breaker to 15 amps. Double check full load on that circuit. If load is too much split the circuit at easiest point and reseed it.

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charlie b

charlie b

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Lockport, IL
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I agree with Don and Daniel. I don't know of any requirement for lighting to be on a 20 amp circuit. Just replace the breaker with a 15 amp version, and the wires can remain in place.
 
mbrooke

mbrooke

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United States
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charlie b said:
I agree with Don and Daniel. I don't know of any requirement for lighting to be on a 20 amp circuit. Just replace the breaker with a 15 amp version, and the wires can remain in place.
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That might be a code violation if wired to 3va per foot. Just make sure its not- and the circuit can do without those 5 extra amps.
 
Ponchik

Ponchik

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Location
CA
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Electronologist
jumper said:
Yes. Where #12 is used a #12 EGC would be required.
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JFletcher said:
If you did use 15A breakers, then wouldnt the portion of the circuit that is in #12 technically be upsized and require a larger ground (for the #14) per 250.122(B)?
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I thought the EGC needs to be upsized only when the conductors are upsized for "voltage drop" conditions. If the distance is not an issue why does the EGC needs to be upsized?
 
jumper

jumper

Senior Member
Location
3 Hr 2 Min from Winged Horses
edward said:
I thought the EGC needs to be upsized only when the conductors are upsized for "voltage drop" conditions. If the distance is not an issue why does the EGC needs to be upsized?
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They revised it and took out the voltage drop clause.

(B) Increased in Size. Where ungrounded conductors are
increased in size from the minimum size that has sufficient
ampacity for the intended installation, wire-type equipment
grounding conductors, where installed, shall be increased in
size proportionately according to the circular mil area of
the ungrounded conductors
 
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