Buss Duct / buss tap/ and accessible disconnects

[Kyell]

Hello,
I am trying to determine in a machine (CNC) environment I have 277/480 buss duct.
I have buss taps (breaker style) sufficient for my machines. However many of the new machines are fed from a transformer that is fed from the buss tap.
Question is, do I need a readily accessible disconnect for the primary feed of my transformer that feeds the machine. Right now ONLY the buss tap can shut off power to transformer
if there is a problem it takes time to access the fiberglass shut off pole. This worries me. but I need a code answer. If none exists I am okay with that answer even if IT leaves me UNEASY.

Bob

 

[petersonra]

450.14

take careful note of what it says about the disconnecting means being accessible

 

[charlie b]

Disconnecting means are NEVER intended to be "emergency power off" devices. They exist to allow maintenance to be performed with no power to the equipment. If someone is receiving a shock, and if you can get to an upstream overcurrent (or simple disconnecting) device, and if you can terminate the event by opening that device, well that is a good thing. But it is not a design requirement that such a possibility exist. For example 450.14 allows the primary side disconnecting means for a transformer to be out of the line of sight, so long as it can be locked open. This tells me that the code authors do not consider it necessary to be able to quickly turn off the transformer in the event of an emergency.

 

[Kyell]

Thank you very much for your response it helps.

Thank you very much for your response it helps.

Thank you very much for your response it helps.