we got a job requiring us to tap into a 3000kva transformer for a 100a feeder. if i am coming out of a customer transformer do i need to follow the any tap rules, the transformer is around 100' away from proposed room with equipment. will i be able to come straight out of transfomer into the room then install my first panel. there will be a 480/240 transformer in the room. i do know at that point i will have a 10' tap rule from transfomer to panel. im just not clear about if i need a disconnet near 3000lva transformer then feed into the equipment room. please any help will be appreciated.
customer 3000kva transformer
- Thread starter mannyb
- Start date
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- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
You need to look at 240.21(C) there are several rules which may be applicable to your installation. In particular, are the conductors inside or outside of the building?
Most likely a disconnect will be needed near the 3000kVA transformer.
the conductors are outside and will feed thru a parking garage.
- Location
- Massachusetts
Need a disconnect and over current protection before going inside.
IWIRE since i am installing disconnect with fuses Can i install a main lug only panel inside equipment room?? can u supply the code reference for that. Thanks
- Location
- Illinois
- Occupation
- retired electrician
You will have to take a good look at the available fault current and make sure your new disconnect is suitable. With a fusible disconnect that should not be an issue.
Where your new circuit enters the building you need a building disconnect. See 225.31 and 225.32.
Also take note of 225.30 if the building being supplied already has power in it.
if the drawings are engineered should all this be determined by A&E firm??. shouldnt prints show all these requirements?? the prints only show the conduit coming out of transformer going thru parking garage then going inside equipment room. the equipment room show the disconnect and panels inside equipment room. there isnt any AFC cal or any AIC for disconnect. Shouldnt prints show at very least AFC cal??
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