Transformer Secondary Conductor protection 240.21(C)(2)

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zemingduan

Senior Member
Location
Philadelphia,PA
Occupation
Electrical Designer
Is this a violation of 240.21(C)(2)? Are the secondary conductors protected?

There is an existing 500 KVA 13.2KV 3ph - 208Y/120V 3ph 4w transformer in the electrical room (not a transformer vault). I am guessing there are (4) sets of #600 MCM copper conductors supply the existing 1600A switch board. There is no OCPD at the transformer secondary. The 1600A switch board doesn't have a main breaker but have (5) 200A switches, (4) 100A switches. The switch board enclosure is right next to the transformer enclosure. There are two other similar existing 1600A switch boards at the other sides of the transformer.

The installations are dated back to 1974. Each 200A feeders supply multiple dorms. The dorms are under renovation and adding some loads such as cooking, micro wave, dishwasher, etc... Not sure if this "violation" need to be corrected.


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jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
This was NEC compliant back in the 70s. The code changed so it is no longer allowed unless it is a 'supervised industrial' facility with qualified on-site maintenance.
 
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