Power feed upgrade? 1

[dubbed]

Hello

i don't know much about electrically stuff but I'm evaluating an upgrade that might be necessary for new hvac equipment being installed.

Currently we have a 200amp 208/3-phase feed and 200 amp 208/1-phase feed i believe.

The load of new hvac equipment adds up to 305 amps at 208v/single-phase
and 55 amps 120v/single phase

A 400amp 208/3-phase feed from the electric company is available and is what is being considered.

What do you think??

 

[DRWeig]

Hiya Dubbed,

Describe your load some more. Is it a bunch of single-phase units or a couple of big ones?

Good on ya,

Goober Dave

 

[dubbed]

The main consumption will be from 10 condensing units.
the condensing unit compressor is rated at 26.4 RLA and 134 LRA (208/1/60)

The rest are fans and other smaller split units.
furnaces and boilers.

 

[DRWeig]

Good on ya,

You have about 70 KVA of air conditioning load total, which would be about 195A if balanced perfectly among the phases. You won't have perfect balance since you have ten units -- but if you spread nine of them evenly, you'll have about 175A per phase base load plus the odd unit -- which will add 25A to two of the phases.

In sum, if you keep your total load below 80% of the new 400A service, you'll have 120A remaining for lights and other non-HVAC loads on all three phases (43 KVA total).

It would be a good idea to evaluate all loads in the form of a panelboard schedule in order to get everything accounted for. A good electrical PE could do this in short order, which is my final advice...

Good on ya,

Goober Dave