Elevator shunt disconnect

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Electromatic

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Virginia
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Master Electrician
I'm working on my first elevator installation. There are separate elevator and fire alarm contractors. I'll pick their brains when the time comes, but I'm trying to get ahead on my understanding.

We installed a Littelfuse shunt trip disconnect.
https://m.littelfuse.com/~/media/el...ttelfuse_lps_operation_maintenance_manual.pdf
LPS2T20R1KGBF3 to be precise

Phase I of this building was several years ago, and there is a 125A shunt trip breaker already in one of the panels for the elevator. Do I even need the shunt breaker if we've installed this shunt disconnect? The elevator machine room is sprinklered, and I understand that power needs to be shut off before the sprinklers are triggered. Is that just power to the controller (i.e. power would still be present in the machine room coming into the disconnect), or should all the power be shut off via the shunt breaker in the panel in a separate room?

If I do need to use the shunt breaker, how would it be connected to the shunt disconnect? It seems like the N.O. fire alarm would be the place to land the breaker shunt signal, but it is also triggering the disconnect shunt. It seems like that could cause issues if one triggers before or after the other. And would I take power from the shunt breaker panel to the disconnect and back or use the 120V from the CPT in the disconnect?

Thanks as always,
 
I'm working on my first elevator installation. There are separate elevator and fire alarm contractors. I'll pick their brains when the time comes, but I'm trying to get ahead on my understanding.

We installed a Littelfuse shunt trip disconnect.
https://m.littelfuse.com/~/media/el...ttelfuse_lps_operation_maintenance_manual.pdf
LPS2T20R1KGBF3 to be precise

Phase I of this building was several years ago, and there is a 125A shunt trip breaker already in one of the panels for the elevator. Do I even need the shunt breaker if we've installed this shunt disconnect? The elevator machine room is sprinklered, and I understand that power needs to be shut off before the sprinklers are triggered. Is that just power to the controller (i.e. power would still be present in the machine room coming into the disconnect), or should all the power be shut off via the shunt breaker in the panel in a separate room?

If I do need to use the shunt breaker, how would it be connected to the shunt disconnect? It seems like the N.O. fire alarm would be the place to land the breaker shunt signal, but it is also triggering the disconnect shunt. It seems like that could cause issues if one triggers before or after the other. And would I take power from the shunt breaker panel to the disconnect and back or use the 120V from the CPT in the disconnect?

Thanks as always,

If the elevator is already connected through a shunt trip breaker which already connects to the fire alarm panel, there is nothing further to do. It appears someone may have asked you to install a redundant device. Or do you mean that there is no elevator installed yet and the 125 amp breaker was installed for future use? If "B", then you still need only one device or the other, not both.
 
Thanks for the response, gadfly. I was getting the feeling that the two shunt devices were redundant. It's hard to say what the plan was when the 125A shunt breaker was provided in the first phase; it seems like it would get complicated tying that into the cab recall, fire alarm, etc. as opposed to the pre-fab disconnect.
If I did want to integrate the shunt breaker with the shunt disconnect, any thoughts on how to connect them? (There's a wiring diagram in the link in the OP.)
 
If I remember right, the shunt trip is supposed to be located at the elevator disconnect, and not at a remote panel.

I would suggest using the new disconnect for the shunt trip, and just use the existing breaker as a feed while leaving its shunt trip disconnected.
 
Thanks for the response, gadfly. I was getting the feeling that the two shunt devices were redundant. It's hard to say what the plan was when the 125A shunt breaker was provided in the first phase; it seems like it would get complicated tying that into the cab recall, fire alarm, etc. as opposed to the pre-fab disconnect.
If I did want to integrate the shunt breaker with the shunt disconnect, any thoughts on how to connect them? (There's a wiring diagram in the link in the OP.)

I wouldn't try to integrate them. Too many moving parts in the design. Don't forget, you have to monitor the source for each shunt coil at the fire alarm panel. Anyone on staff familiar with elevators (once you leave) is going to expect that they go to one location and reset one breaker, not two.
 
If I remember right, the shunt trip is supposed to be located at the elevator disconnect, and not at a remote panel.

I would suggest using the new disconnect for the shunt trip, and just use the existing breaker as a feed while leaving its shunt trip disconnected.

That will depend on jurisdiction. I know that it isn't true in NJ.
 
I would suggest using the new disconnect for the shunt trip

Yes....I think their intent was to have the new switch/shunt control everything.
Those elevator switches are not cheap (as you know)
 
Thanks, all. I plan on just using the shunt disconnect but will make sure that is copacetic with the fire and elevator people.

The shunt breaker that's there from the 1st phase I'm sure was intended for the elevator, but I don't know what the plan would have been to use it--given that the disconnect is required to be in the elevator machine room and the need for various contacts, relays, etc. to communicate with the elevator control and fire system. It would have been nice to save the money on that switch, though!
 
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