Elevator Connected to Manual Transfer Switch

[Npstewart]

I have a project where a generator is going to be added to a building with an elevator. The Transfer switch for the generator is going to be a Manual Type (for various reasons). The Generator is an optional type system per NEC Article 702.

According to the Elevator installer, the generator power is not required, but IF its provided, the transfer switch must be Automatic type. Has anyone ever heard of this?

The code cited is ASME A17.1-2013/CSA B44-13.

Specific Code Section = 2.27.2.2

"The Transfer between the normal and the emergency or standby power system shall be automatic".

The code cited is brief and does not have any explanation or further info. On one hand Im thinking that maybe this section is stating that the elevator cannot be physically re-wired to a standby power source. On the other hand, maybe its correct? The code does not say "Transfer Switch" it just says "Transfer".


Thanks in Advance.

 

[steve66]

It does look like the requirement is for an auto transfer switch.

If you read on, it talks about what happens if the generator isn't sized for all the elevators that are connected, and allows a selector switch to pick the elevator.

I can assume the intent behind requiring an automatic ATS is to keep people from being trapped in a dark elevator while waiting for someone to transfer the switch to generator power.

Or maybe they are worried the generator might quit, and the switch may won't transfer back to utility even if utility power has been restored.

 

[charlie b]

If the building loses normal power before the generator is installed, what happens to the people in the elevator? How would that change if the generator is only connected to a portion of the building loads, and if the elevator is not on that portion? If the building presently has an elevator and if the building does not already have a generator rated for 700 or 701 service, then the elevator is not part of any life safety egress path. Therefore, it need not be supplied from the generator. Is this an option for you?

 

[Npstewart]

If the building loses normal power before the generator is installed, what happens to the people in the elevator? How would that change if the generator is only connected to a portion of the building loads, and if the elevator is not on that portion? If the building presently has an elevator and if the building does not already have a generator rated for 700 or 701 service, then the elevator is not part of any life safety egress path. Therefore, it need not be supplied from the generator. Is this an option for you?

Agreed. It definitely an option although not the most ideal one. I may proceed with an additional small ATS just for the generator. My state doesent require batteries for the elevator to lower to the ground level so removing it from elevator power means whomver is in there just has to wait for the power to come back on.

This code section isn’t very well written. After reading through it, I’m definitely not a fan of “the elevator code”.

 

[steve66]

It does seem odd since I would assume having a manual transfer switch would be better than no backup power.

And the requirement for an ATS might push many designs toward no backup power for the elevator.

 

[Jraef]

It’s been a long time since I was connected to the elevator industry but as I recall, the only time you were required to have a backup generator for elevators circuits at all was in health care facilities where evacuation of patients can’t be done via stairs. Otherwise, you don’t use the elevators in an evacuation emergency. So if you WANT to have a backup generator in those circumstances, you CAN use a manual transfer switch since the generator is basically for your own convenience. But I also recall there may be some connection to the TYPE of elevator system as well in that a hydraulic elevator can lower a car to the next floor down without needing line power, but a traction elevator cannot. It’s been too long though, I think I killed off too many of those brain cells with beer a decade ago. The point is, there was no “one size fits all” answer, it was complicated by a number of issues. That’s why there are elevator specialty contractors, they have to know and keep up with this, and it changes frequently, especially right after high profile accidents. I had to get out...

 

[mtfallsmikey]

It’s been a long time since I was connected to the elevator industry but as I recall, the only time you were required to have a backup generator for elevators circuits at all was in health care facilities where evacuation of patients can’t be done via stairs. Otherwise, you don’t use the elevators in an evacuation emergency. So if you WANT to have a backup generator in those circumstances, you CAN use a manual transfer switch since the generator is basically for your own convenience. But I also recall there may be some connection to the TYPE of elevator system as well in that a hydraulic elevator can lower a car to the next floor down without needing line power, but a traction elevator cannot. It’s been too long though, I think I killed off too many of those brain cells with beer a decade ago. The point is, there was no “one size fits all” answer, it was complicated by a number of issues. That’s why there are elevator specialty contractors, they have to know and keep up with this, and it changes frequently, especially right after high profile accidents. I had to get out...

No, your brain cells are fine. Emergency generator/ATS/shunt trips usually are required on "high rise" buildings, either above a certain number of stories/ building height. Traction elevators cannot, that is correct.