Temporary 500 Ton Chiller - Single vs Dual Source Feed

[Anthony Giordano]

Hey all. I have a little difficult situation that I am dealing with, that I need some assistance with. I am doing a Chiller Replacement project in Albany, NY, where two (2) 500 Ton water cooled chillers are being replaced by two (2) new 500 Ton air cooled chillers. While the demolition and new construction is going on, a temporary 500 Ton air cooled rental chiller is being utilized for the plant. This chiller is dual circuit, with MCA's of 490A & 561A respectively. The recommended MOP's are 600A & 700A respectively.

In the double-ended Main-Tie-Main 480V 2000 KVA switchboard that feeds the plant, I only have one 1600AF circuit breaker with adjustable trip available to use to feed this temp chiller. I would like to use this single source 1600A C/B in order to feed the chiller, set the adjustable trip to 1200A, then have the temporary cables feed from one circuit breaker over to the other. Is this permissable?

The Trane rep. said the following in an email yesterday: In regards to the question about the power, am I clear in understanding that the customer wants to have a 1200 amp service break out into two separate 600 amp breakers prior to feeding our chiller? Or are they wanting to use a single 1200 amp source to provide power to our two separate ckts? I would be concerned that code would not allow a single 1200 amp source to provide power to two separate ckts, our recommendation would be to have a 600 Amp and 700 Amp Breaker(Sized for MOP) to feed the chiller.  This would be up to electrical contractor and inspector though.

Thanks in advance for any feedback that I might receive on this thread.

 

[augie47]

If the manufacturer calls for 60 and 700 amp OCP device you must provide that {440.22(C)M & 110.3(B)}. Apply the tap rules it's perfectly permissible to feed the two individual OCP devices from the one breaker.
(If you elected not to do that and the chiller failed, guess who would be held responsible)

 

[gadfly56]

If the manufacturer calls for 60 and 700 amp OCP device you must provide that {440.22(C)M & 110.3(B)}. Apply the tap rules it's perfectly permissible to feed the two individual OCP devices from the one breaker.
(If you elected not to do that and the chiller failed, guess who would be held responsible)

I think that's what he intends to to.

then have the temporary cables feed from one circuit breaker over to the other.

It sounds like the rep wants the breakers back in the MDP or equivalent.

 

[Ingenieur]

It is not clear to me
1 1600 set to 1200 feeding both chiller connections in parallel
or
1 1600 set to 1200 feeding 2 600's, each with a ckt to the 2 chiller connections

apparently the Trane guy is not clear either

What governs temporary construction wiring?

 

[priyankasethi]

Chilled water frameworks are cooling frameworks that circle chilled water all through a structure for cooling and dehumidifying a structure's air. Chilled water frameworks are shut circle frameworks, implying that the framework water is ceaselessly recycled and not presented to climatic weight, like homegrown water frameworks. Most little chilled water plants-up to roughly 200 tons in limit use scroll blowers for creation of chilled water.

The explanation: An air-cooled framework just requires chillers and chilled water siphons, though a water-cooled framework requires the chillers, chilled water siphons, condenser water siphons, and cooling towers for completely practical framework and to receive the energy effectiveness rewards. A chiller plant isn't finished without the siphoning course of action to circulate chilled water all through the structure or grounds to the chilled water curls. Due to the capacity to shift stream, these frameworks kill the requirement for auxiliary dissemination siphons and utilize different siphons in corresponding to serve the whole chilled water framework, remembering the chillers and any curls for the framework. Chilled water plants and chillers are dynamic frameworks that depend on cautious examination to decide the correct chiller for a structure.