Switching lighting circuits

[Isaiah]

Contractor wants to run both emergency lighting and normal lighting from the same three way switch using double-pole double throw toggle... Is there any problem mixing this at the same switch provided separate conduits are run to the switch from different power sources, per Art 700?

 

[480sparky]

Why would you want emergency lighting on a switch?

 

[Isaiah]

These LEDs have two lamps - one for normal and one for emergency.

 

[480sparky]

You'd still be switching off your E-light, no? If you do that, it'll lose power and turn on.

 

[Isaiah]

You'd still be switching off your E-light, no? If you do that, it'll lose power and turn on.

No because he just wants to run the emergency wiring through the switch without actually terminating it. Only the dirty power would be actually switched...doesn’t make a lot of sense but I couldn’t see a violation doing it that way


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[480sparky]

How do you run a circuit 'through a switch' ...' without terminating' it? And how is 'dirty power' involved?

 

[infinity]

You cannot mix EM and normal in the same raceway is that you'll end up with?

 

[480sparky]

I'm totally lost here. Are the e-lights fed from an emergency back-up system (UPS, generator etc)? Or are they simply a strip of LEDs built into the fixture that will come on when power is lost?

 

[Isaiah]

I'm totally lost here. Are the e-lights fed from an emergency back-up system (UPS, generator etc)? Or are they simply a strip of LEDs built into the fixture that will come on when power is lost?

Yes, they're both

 

[roger]

Yes, they're both

Then it's as Infinity says, the EM conductors can not be in the same raceways as the normal conductors.

Roger

 

[Isaiah]

Then it's as Infinity says, the EM conductors can not be in the same raceways as the normal conductors.

Roger

Thank you gentlemen. That’s exactly what I thought


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[480sparky]

I'm still trying to figure out the use of the switch, and how it is not terminated but still is dirty power.

 

[infinity]

I'm still trying to figure out the use of the switch, and how it is not terminated but still is dirty power.

Sounds like both the EM and normal circuits enter the switch box, the normal is switched, the EM passes through to the fixture along with the normal switch leg in the same raceway.

This part from the OP has me confused "using double-pole double throw toggle ", sounds like both the EM and normal go through the switch.

 

[480sparky]

Sounds like both the EM and normal circuits enter the switch box, the normal is switched, the EM passes through to the fixture along with the normal switch leg in the same raceway.

So what's the DPDT switch for?

 

[Isaiah]

So what's the DPDT switch for?

Judging from this string he doesn’t need it. Single pole only will work since you can’t run both through the same switch anyway


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[Another C10]

I'm still trying to figure out the use of the switch, and how it is not terminated but still is dirty power.

It almost sounds like the emergency lighting circuit and the "dirty" or regular lighting circuit are both running through a common switch box while the emergency does not terminate at that point and just feeds on through, whereas the standard lighting circuit switches a portion of the tubes/bulbs at the same fixture. The emergency circuit typically is tied directly into the battery pack of the fixture normally from a completely different panel, unless its 1 circuit that provides a constant hot for the battery and a switched version for the general fixture lamps. That may be legal, I'd have to look it up, using one circuit to be manipulated for a constant and switched design of a combo two purposed fixture.

 

[Isaiah]

It almost sounds like the emergency lighting circuit and the "dirty" or regular lighting circuit are both running through a common switch box while the emergency does not terminate at that point and just feeds on through, whereas the standard lighting circuit switches a portion of the tubes/bulbs at the same fixture. The emergency circuit typically is tied directly into the battery pack of the fixture normally from a completely different panel, unless its 1 circuit that provides a constant hot for the battery and a switched version for the general fixture lamps. That may be legal, I'd have to look it up, using one circuit to be manipulated for a constant and switched design of a combo two purposed fixture.

I’m looking at 700.12 (2017)NEC, unit equipment. You could do the last scenario you noted. You wouldn’t need the EMERG GEN, or UPS back up power or separate conduit for that matter. You could tap off the hot leg of the first toggle switch and drive the exit LEDs for example using normal power - that is the same power source for the normal lighting


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