Transformer Protection

Status
Not open for further replies.
P

pct_elect

Member
I have searched a bit and have not seen this discussed yet.
Building an industrial control panel fed from 480V/3Ph. I need to run existing 120V/1Ph stuff in addition to the 3Ph equipment. I figure just under 90 Amps of 120V/1Ph will be needed = 15KVA transformer.
My question is where can I find a 150A/1P circuit breaker for the secondary?
I need 14 circuits to be from the 120V/1Ph, each with its own breaker all enclosed in the NEMA 12 enclosure.
Do I need to split this into two 70A chunks and have those feed the individual circuit breakers?
 
There are all kinds of ways to handle this. I might be inclined to make the secondary a 120/240V 3 wire and feed it into a regular old panelboard. they are pretty cheap, and you don't have to fool around with busing the individual CBs or finding someplace to hookup the neutrals and grounds. also a nice place to have breaker locks installed so you can lockout each circuit seperately.
 
transf

transf

I would agree with petersonra, I think you will find it a lot simplier to split it up into a 240/120 panel. Everything you need would be readily available..
DP breaker, retaining clip, SP breakers, etc ..all shelf stuff.
 
Well...not everything is ON/OFF.
Several of the circuits must interface to the control circuitry and is seems that running in and out of 2 separate boxes just to access a housing for some breakers is a bit cumbersome not to mention the required additional real estate. Ten Motor starters (some single phase), float switches, timers, etc.
The Main Control Panel will be 5ft x 4ft with enough room to contain everything in a dust-tight enclosure and boy, a 150A single pole breaker would sure make things tidier.
But splitting it into 240/120 might just be the way I need to go anyhow.
Thanks for the input.
 
Status
Not open for further replies.
Top