1200 amp service

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rockman33

Member
Location
Alabama
I am getting a 1200 amp service installed that is going to feed 2 300HP 480v motors and a small 480 - 120/208v transformer to power a panel. If I put in a 1200a fuseable disconnect can I run a tap conductor off the secondary immediately to a trough and tap off that conductor to feed my other disconnects. If I am wrong what is the proper way of feeding them?
 

iwire

Moderator
Staff member
Location
Massachusetts
If this service is a 480Y/277 you may have issues with 230.95.

There is nothing directly wrong with your approach however I might use a 1,600 amp main lug only panel with six or less breakers in it feeding the equipment and serving as the service disconnecting means.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I agree with iwire.

The only problem I can see would be if you are using the fuses to address an available fault- current issue. If so, you could look at multiple fusible disconnects rather than one main.
There are several routes you can take to avoid the 1000 amp GF requirement.
 

kwired

Electron manager
Location
NE Nebraska
I'd likely run separate conductor from source to each disconnect and not worry about taps unless paralleling them helps you with voltage drop problems. All grouped in one location of course, you only have three service disconnecting means at this point. Potential future loads could change that plan though.

Not sure off top of head what size conductor is needed for a 300 hp motor maybe around 400 amps FLA?
 
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