Disconnect for Air Cooled Chiller

[AggieEE07]

I have (3) 500 ton air cooled york chiller units going in that have single point connections. The chiller package has 4 compressor units (2 units from 2 control sections)with . Both control sections are contained within a single control cabinet and have their own molded case breaker capable of being locked out and operated externally while the control panel is closed. The single point connection within the cabinet shows our single point feed cables landing on a terminal block and from the terminal block are wired to each of the (2) breakers. All controls are downstream of the breakers.

Is there any reason to provide a single point disconnect? I realize it would be better practice but this is a temporary installation and it would be nice to eliminate the cost of (3) Nema 4X 1000A disconnects.

 

[alehman]

I don't know of any code requirement for a single disconnect.

Alan
“The engineer's first problem in any design situation is to discover what the problem really is.” Unk.

 

[DRWeig]

Agree with Alan -- if the first thing your cables hit are the line side of 2 circuit breakers, the breakers should suffice as disconnecting means.

Good on ya,

Goober Dave

 

[PHovnanian]

I think you can label the equipment to indicate that both breakers must be opened for disconnection. Check with the AHJ.

 

[peebee]

Is there any disconnect for the motor? Or do those breakers only disconnect the controls? If not, you will need an additional local disconnect per 430.102 unless you fall under one of the exceptions to 430.102. That disconnect would most likely be placed just ahead of your single-point connection.