240.21(C)(3)

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MikeVia

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Does this apply when sizing transformer cable secondary for a facility where the high side of the transformer is connected to the Utility at say 15kV? Where the secondary cables, less than 25 ft., at 480V, may terminate at a bus with multiple 480V overcurrent devices connected.

Thanks for any insight on this.
 
MikeVia said:
Does this apply when sizing transformer cable secondary for a facility where the high side of the transformer is connected to the Utility at say 15kV? Where the secondary cables, less than 25 ft., at 480V, may terminate at a bus with multiple 480V overcurrent devices connected.

Thanks for any insight on this.
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What would make this an "Industrial Installation" or not.
 
MikeVia said:
Does this apply when sizing transformer cable secondary for a facility where the high side of the transformer is connected to the Utility at say 15kV? Where the secondary cables, less than 25 ft., at 480V, may terminate at a bus with multiple 480V overcurrent devices connected.

Thanks for any insight on this.
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Where is the service disconnect?
 
electrofelon in Post #3 asks a key question.. where is the service disconnect ??
(is the transformer a utility transformer feeding several service disconnects or is the transformer a par tof the facility wiring ?)
 
the transformer, 15kV delta to 480V wye, is owned by the utility. It is located on the facility property. The secondary cables terminate directly on a bus. Connected to the bus are multiple, individual protective device breakers. These breakers serve multiple loads, including pump motors and sub panels.
Does the transformer secondary cable have to be sized according to 240.21(C)(3)?
 
electrofelon said:
Ok well we CAN say that 240.21(C) does NOT apply since these are either utility conductors or service conductors. 240.21 doesn't apply to service conductors.
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OK, thank you, electrofelon. That's confirmation that I was hoping for. I think the "service point" is the low side terminals of the utility transformer, and the cable from the transformer to the disconnects is the "service conductor".
 
MikeVia said:
OK, thank you, electrofelon. That's confirmation that I was hoping for. I think the "service point" is the low side terminals of the utility transformer, and the cable from the transformer to the disconnects is the "service conductor".
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That's often the case and Art 230 will apply.
 
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