Circuit breakers as switches

[Coppersmith]

I looked a job today where twelve GE circuit breakers are being used to control 120v florescent lighting in a warehouse. These breakers are worn and one has totally failed. If my understanding is correct, the only time a breaker can be used to control lighting is if they are marked for "switch duty" (SWD).

The owner is asking me to put in 12 toggle switches to control the lighting so he can avoid using the breakers. He specifically does not want a lighting contactor. There is plenty of room to do this near the surface-mounted panel, however I'm running up against the derating rules. If I run two short pieces of conduit with 12 conductors each (12 switch legs in, 12 out) to a switch box, I have to derate 50%. Since I want 20 amp circuits, I would have to run #10 which seems like a pain.

The switch box could be 6 4x4 deep boxes chase nippled together with 2 switches each. Or I could use two pole switches and switch two circuits at a time with less boxes.

An alternative I'm considering is mounting a 12 slot Cutler-Hammer subpanel with SWD breakers, but the same derating rules apply as far as I know. I can be a few inches away from the main panel.

Suggestions?

 

[infinity]

Derating only applies when your raceways exceed 24" so short sections between your components will eliminate the need to derate the conductors. The old CB's were generally listed as switch duty (SWD), newer ones are typically listed as HID for high intensity discharge lighting.

240.83(D) Used as Switches. Circuit breakers used as switches in120-volt and 277-volt fluorescent lighting circuits shall be
listed and shall be marked SWD or HID. Circuit breakers
used as switches in high-intensity discharge lighting cir-
cuits shall be listed and shall be marked as HID.

 

[roger]

I looked a job today where twelve GE circuit breakers are being used to control 120v florescent lighting in a warehouse. These breakers are worn and one has totally failed. If my understanding is correct, the only time a breaker can be used to control lighting is if they are marked for "switch duty" (SWD).

Actually that only pertains to florescent and HID lighting.

There is plenty of room to do this near the surface-mounted panel, however I'm running up against the derating rules. If I run two short pieces of conduit with 12 conductors each (12 switch legs in, 12 out) to a switch box, I have to derate 50%. Since I want 20 amp circuits, I would have to run #10 which seems like a pain.

I can be a few inches away from the main panel.

Suggestions?

See 310.15(B)(3)(2)

Roger

 

[Coppersmith]

Derating only applies when your raceways exceed 24" so short sections between your components will eliminate the need to derate the conductors. The old CB's were generally listed as switch duty (SWD), newer ones are typically listed as HID for high intensity discharge lighting.

So if I run 24" to the first 4x4 box and then I have several boxes chase nippled together, do I have to derate the wires that go to the furthest box since the total length would exceed 24"?

 

[petersonra]

So if I run 24" to the first 4x4 box and then I have several boxes chase nippled together, do I have to derate the wires that go to the furthest box since the total length would exceed 24"?

I don't see how it could be properly interpreted that way. The nipple ends at the box and then a new one starts.

Personally, I would like to see someone use this provision to run a crap load of wires in a conduit using 24" nipples between boxes just to see what a picky inspector could do about it.

 

[ActionDave]

So if I run 24" to the first 4x4 box and then I have several boxes chase nippled together, do I have to derate the wires that go to the furthest box since the total length would exceed 24"?

I don't remember the wording, but I know the 24" rule only mentions raceways. If you read it carefully you could run two feet of pipe, install a box, run two more feet of pipe, and so on. I'm sure that's not what was meant to be allowed, but it is how the section reads.

 

[infinity]

I don't remember the wording, but I know the 24" rule only mentions raceways. If you read it carefully you could run two feet of pipe, install a box, run two more feet of pipe, and so on. I'm sure that's not what was meant to be allowed, but it is how the section reads.

I agree, that's how it's worded.

 

[JFletcher]

While I would not wire lights w/o switches in the circuit, just utilizing the breakers, now that it is wired that way, what's the big deal with replacing the breakers every so often? 12 1p 20A GE breakers arent expensive and the labor is nil compared to adding onto the circuit.

If you really want the switches, why not just run 3 pieces of conduit to a switchbox instead of 2? 12 switch = 24 CCC/3 = 8/pipe = 70% derating x30A = 21A, still enough for a 20A breaker

 

[Coppersmith]

If you really want the switches, why not just run 3 pieces of conduit to a switchbox instead of 2? 12 switch = 24 CCC/3 = 8/pipe = 70% derating x30A = 21A, still enough for a 20A breaker

I hadn't thought of that.

As others have mentioned, the point seems moot if I stay within 24" which I can.

 

[blkmagik21]

I don't see how it could be properly interpreted that way. The nipple ends at the box and then a new one starts.

Personally, I would like to see someone use this provision to run a crap load of wires in a conduit using 24" nipples between boxes just to see what a picky inspector could do about it.

I've ran from an exterior panel into a house and ran all the romex home runs through a 1-1/2 chase nipple. The inspector tried calling me and saying I had too many wires in it (23) but they fit and the code was on my side so I won.


Sent from my iPhone using Tapatalk

 

[JFletcher]

I hadn't thought of that.

As others have mentioned, the point seems moot if I stay within 24" which I can.

If you have box, conduit (of any length), panel, isnt that a complete raceway?

 

[ActionDave]

If you have box, conduit (of any length), panel, isnt that a complete raceway?

Yes, but complete raceways 24" or less don't require any derating.

 

[kwired]

While I would not wire lights w/o switches in the circuit, just utilizing the breakers, now that it is wired that way, what's the big deal with replacing the breakers every so often? 12 1p 20A GE breakers arent expensive and the labor is nil compared to adding onto the circuit.

+1

GE plug on breakers are not much more expensive then a 20 amp spec grade switch is.

Throw lighting contactors into the mix and total installation/possible maintenance cost jumps pretty fast.

 

[roger]

If you have box, conduit (of any length), panel, isnt that a complete raceway?

See post #3

Roger

 

[jim dungar]

The old CB's were generally listed as switch duty (SWD), newer ones are typically listed as HID for high intensity discharge lighting.

Switching Duty (SWD), is an optional rating for 15 and 20A single pole breakers. HID is an equivalent type of rating used on all other breakers.
As I recall, SWD involved on-off cycling as well as contact material, for the most part an SWD breaker is tested similar to a standard wall switch.

 

[hbiss]

I'm with the others here who recommend just replacing the breakers and calling it a day. However, I was asked a few times to provide switches next to a panel just to keep people out of the panel who always seemed to mess with circuits not associated with the lighting. I used a 1900 type gang box that is available up to 9 gang. Once your wiring is in the box it is no longer subject to bundling because the conductors are far enough apart.

-Hal

 

[Coppersmith]

I'm with the others here who recommend just replacing the breakers and calling it a day. However, I was asked a few times to provide switches next to a panel just to keep people out of the panel who always seemed to mess with circuits not associated with the lighting. I used a 1900 type gang box that is available up to 9 gang. Once your wiring is in the box it is no longer subject to bundling because the conductors are far enough apart.

-Hal

Hmmm. Client is asking for switches. Wants switches. I quoted him $1300 to put in switches and replace the worn breakers. I suppose I could convince him to just let me change the breakers for $200 instead. But I won't. No wonder so many EC's go out of business.