620.62 Selective Coordination

Status
Not open for further replies.
A

anbm

Senior Member
Location
TX
Occupation
Designer
620.62 Selective Coordination. Where more than one driving
machine disconnecting means is supplied by a single feeder,
the overcurrent protective devices in each disconnecting means
shall be selectively coordinated with any other supply side over‐
current protective devices.

If (3) elevators are fed from same electrical panel on their own circuit,
do we need to comply with above rule?

Or this rule mean one dedicated circuit feeds all (3) elevators?
like via a common wireway.
 
anbm said:
620.62 Selective Coordination. Where more than one driving
machine disconnecting means is supplied by a single feeder,
the overcurrent protective devices in each disconnecting means
shall be selectively coordinated with any other supply side over‐
current protective devices.

If (3) elevators are fed from same electrical panel on their own circuit,
do we need to comply with above rule?

Or this rule mean one dedicated circuit feeds all (3) elevators?
like via a common wireway.
Click to expand...

Yes, I believe it would apply. The idea is that something like a short circuit at one elevator motor should only trip the OCP on that elevators disconnect. That way, a problem with one elevator doesn't cause all 3 elevators to stop.

So the OCP in each elevator disconnect should be coordinated with the main breaker in the panel (if there is a main breaker) and also with any breakers upstream including the breaker supplying the panel feeder.
 
My interpretation of the question was that from the same panel, three circuits fed three elevator systems, that each system had its own disconnecting means, and that each of those disconnecting means had an overcurrent device of its own. That would mean that the conductors from each of the three circuits comprised feeders. Since a single feeder did not supply more than one elevator, the rule would not apply.

Now, can someone confirm or refute my interpretation? For if there is no OCPD at the elevator system, then the circuits are branch circuits not feeders, and the rule would apply.
 
charlie b said:
My interpretation of the question was that from the same panel, three circuits fed three elevator systems, that each system had its own disconnecting means, and that each of those disconnecting means had an overcurrent device of its own. That would mean that the conductors from each of the three circuits comprised feeders. Since a single feeder did not supply more than one elevator, the rule would not apply.

Now, can someone confirm or refute my interpretation? For if there is no OCPD at the elevator system, then the circuits are branch circuits not feeders, and the rule would apply.
Click to expand...

The single feeder, in the case of the branch circuits originating on separate breakers in a panel, would be the panel feeder. In my opinion, selective coordination is required between the branch breakers in the panel and the line side panel OCPD.
 
Status
Not open for further replies.
Top