Transformer Disconnect

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PEL11

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I'm coming out of the MDP and running about 100 feet to a new electrical room, and in the room I'm setting a new transformer. My drawings show a disconnect on the primary side of the transformer, do I really need one?
 
Local ammendments may require the xfmr disconnect though. I've run into that requirement but can't remember which state it was.
 
Transformer Disconnect

How about if I came out of the MDP, when 10 feet to a transformer, left the transformer and went 100 feet to a new electrical room. Would the code require a disconnect on the secondary side?
 
PEL11 said:
How about if I came out of the MDP, when 10 feet to a transformer, left the transformer and went 100 feet to a new electrical room. Would the code require a disconnect on the secondary side?
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Probably.

For 600V or less primaries the NEC never requires a secondary disconnect. However, if the primary OCPD can only be greater than 125% of FLA if a secondary OCPD has been provided. Also, the secondary conductors neede to be protected ( there are several ways in article 240) so that usually means a secondary disconnect will be used. And finally 408 requires that a lighting and branch circuit panelboard have a main device some place.
 
engy said:
City of Chicago is one.
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Engy

Can you site the Chicago Code Section that requires the primary disconnect? I've heard that it is a requirement, but have not been able to locate it.
Thanks,
Brian
 
PEL11 said:
How about if I came out of the MDP, when 10 feet to a transformer, left the transformer and went 100 feet to a new electrical room. Would the code require a disconnect on the secondary side?
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Many factors come in to play on this one.

Possible tap rule consideration ? Is the feeder on the secondary side ran outside of the building ? What type of load is on the secondary side. Electrical room ? Remote building or structure?

Without more info I could not give a definte answer that is backed up with NEC requirements , not to mention additional state,city,county,etc. codes.

My opinion based on the info stated would be maybe.:D

ibew441dc
 
:cool: new question related; coming from a 10' gutter, does a 400 amp service, when the service entrance conductors do not exceed 15' in length, terminate to a main breaker, have to be fused? there is a total of 7 services that enter that building. Only three are in use. The building caught fire not too long ago
 
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My original question, or at least what it should of been last night was, does it have to be a fused disconnect? Since the S.E.C. do not exceed 15' in lenght, can't it be a non-fusable disconnect?
 
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