Separate vs. Dedicated Branch Circuit

[dixiedrafting]

In elevator pits and/or machine rooms the NEC requires that the circuit(s) for light(s) and receptacle(s) should be seperate. What does separate mean? How about separate branch circuit vs. dedicated branch circuit? Can a separate branch circuit extend beyond the elevator pit or machine room (i.e. if machine room light and receptacle are served from same branch circuit as corridor lighting)? The code uses the term "Separate" in 620-22(a) and "Dedicated" in 620-22(b) what's the difference?

 

[Shockedby277v]

620.24 (A)

IMO a seperate branch circuit would mean it can only be used for the pit lighting and the receptacle and not part of a multiwire branch circuit. No where else can it be used.

 

[infinity]

The terms separate branch circuit and dedicated branch circuit are not defined in Article 100. My guess is that something that is separate is not part of something else. Therefore, the circuit would solely supply the pit lighting and receptacles and nothing else. I'd guess that you could call this a dedicated circuit since its dedicated only to the pit. IMO this could be fed from a MWBC and still be a separate branch circuit as required in 620.24(A).

 

[LarryFine]

"Separate" implies separate from one another. Both words ("lights" & "receptacles") are identified in the sentence. "Dedicated" only requires that a single item be named. That's how I see it.

However, one of my best friends is an elevator engineer, and we've discussed this. The concern is not the same as kitchen appliance and lighting circuits: a malfunction on the former should not disable the latter.

That's the intent of the second sentence of 260.24(A), so it obviously is okay for the lighting to be on the same circuit as the GFCI receptacle, just not on its feed-through load terminals.

In this case, "separate" means separate from other elevator circuits, so power and lighting are available even with the elevator power system completely de-energized. Pit work is often done with a dead elevator system.

 

[George Stolz]

This is an odd one.

620.24 Branch Circuit for Hoistway Pit Lighting and Receptacle(s).
(A) Separate Branch Circuit. A separate branch circuit shall supply the hoistway pit lighting and receptacle(s).
Required lighting shall not be connected to the load side of a ground-fault circuit interrupter.
(B) Lighting Switch. The lighting switch shall be so located as to be readily accessible from the pit access door.
(C) Duplex Receptacle. At least one 125-volt, single-phase, duplex receptacle shall be provided in the hoistway pit.

It has to be a misnomer. Or, at least, just not in keeping with the rest of the code. It should be rewritten to follow the "A circuit shall be provided...This circuit shall have no other outlets" formula. This is not terribly clear.

Can a separate branch circuit extend beyond the elevator pit or machine room (i.e. if machine room light and receptacle are served from same branch circuit as corridor lighting)?

No, see 620.37(A):

620.37 Wiring in Hoistways, Machine Rooms, Control Rooms, Machinery Spaces, and Control Spaces.
(A) Uses Permitted. Only such electric wiring, raceways, and cables used directly in connection with the elevator or dumbwaiter, including wiring for signals, for communication with the car, for lighting, heating, air conditioning, and ventilating the elevator car, for fire detecting systems, for pit sump pumps, and for heating, lighting, and ventilating the hoistway, shall be permitted inside the hoistway, machine rooms, control rooms, machinery spaces, and control spaces.