Emergency Light with 3-way switch (NEC 700.20)

[beaucephas]

I need some help clarifying something. We design many projects where we use a standby generator to provide emergency power to egress lighting. Typically we use a generator transfer device such as the Bodine GTD so that the emergnecy lights can be switched with the normal power lights, but still automatically come on upon loss of normal power.

NEC 700.20 clearly says that emergency lighting cannot be connected to a 3-way switch. Does this requirment still apply when you use a generator transfer device since the device brings the lights on automatically regardless of switch position? thank you.

 

[marinesgt0411]

For 1) emergency lights should not be switched except to turn ON emergency lights. 2) emergency lights should come on with lose of power, take out the word normal. That is my opinion and I am sticking to it.

 

[Strathead]

I need some help clarifying something. We design many projects where we use a standby generator to provide emergency power to egress lighting. Typically we use a generator transfer device such as the Bodine GTD so that the emergnecy lights can be switched with the normal power lights, but still automatically come on upon loss of normal power.

NEC 700.20 clearly says that emergency lighting cannot be connected to a 3-way switch. Does this requirment still apply when you use a generator transfer device since the device brings the lights on automatically regardless of switch position? thank you.

The GTD has two sources of power. One normal and one emergency circuit. The 3 way switches you refer to switch the NORMAL power circuit. NEC 700.20 actually clearly refers to switches that control emergency lighting circuits. The emergency circuits are only switched by the circuit breakers in this scenario. So no problem.


Also, as a side note. 700 deals with emergency circuits. This is defined and circuits legally required and classed as emergency by (paraphrase) government entities. They are not necessarily emergency circuits just because you put them on a Generator.

 

[iwire]

For 1) emergency lights should not be switched except to turn ON emergency lights.

Not possible, often the emergency lights are the same fixtures that light the room normally and there are reason where the emergency fixture must be shut off, say a conference room where they show videos etc.

The code allows shutting them off if you provide an automatic way for them to bypass the off switch during a power failure.

 

[thepij]

Unless I am mistaken - if your generator is supply Emergency Power, then it is not a backup generator. It is an emergency generator and will have to follow respective code requirements. If there are non-emergency power circuits on the generator, then the wiring for both types of loads will have to be seperated.

 

[Dennis Alwon]

Let me get this straight. The op has a generator which is connected to the switch leg of light fixtures that are normally on a 3 way switch??? Is this correct? Is so I don't see a problem since the switches would be inoperative.

 

[ngd4130]

Not possible, often the emergency lights are the same fixtures that light the room normally and there are reason where the emergency fixture must be shut off, say a conference room where they show videos etc.

The code allows shutting them off if you provide an automatic way for them to bypass the off switch during a power failure.

IMO, I am not sure why a designer would design a conference room with emergency lights in the fixtures on 3-way switches. Other options are available, namely, battery back-up either in the fixtures or as wall mount units. :?