What is the hazard category?

[rbalex]

At the moment, only consider Table 130.7(C)(9)(a) in the NFPA 70E‑2004 edition.

Consider a 6.6kV load interrupter switch that, ?in theory,? will only be operated against a dead bus; however, the dead bus is only assured by administrative procedures; i.e. there are no preventative electrical or mechanical interlocks.

What is the hazard category? If you have NFPA 70E‑2004 substantiation, feel free to explain.

 

[richxtlc]

I need a little more information. Is the load interrupter being operated with the enclosure closed, operated locally or remotely? Administrative controls do not constitute a dead bus, only testing can verify absence of potential. If work is to be performed, then the equipment and/or the bus needs to be grounded depending on where the work is to be accomplished.
The fact that it is a load interrupter indicates that it can be operated with the bus alive when disconnecting load. Why are there administrative controls to ensure that the interrupter is operated when the bus is dead? Is there a problem with the interrupter?

 

[rbalex]

I genuinely appreciate the request for clarification.

You may assume the operation is expected to be a routine operating activity, closed door, with a external, local operator.

I can also disclose that operation could, in the absense of the administrative controls, connect the bus to ground

 

[zog]

HRC 2 if you fall withing the limitations of the tables.

 

[rbalex]

Thanks for everyone's votes and comments-I'm leaving the poll open for another week or so and I'd appreciate more participation.

I cited NFPA 70E-2004 in the poll because it is the latest edition specifically mentioned in Fed/OSHA's Electrical Standard, Final Rule although the Final Rule's content basically claims to follow 70E-2000. Cal/OSHA has also just adopted a new set of "Low-Voltage" and "High-Voltage" Electrical Safety Orders "more-or-less" based on the Fed/OSHA Final Rule. All three documents have considerable content that an electrical system design needs to comply with. The California Orders are sufficently different that I'm still digesting them. While California is a "State Plan" State, Fed/OSHA still looks over its shoulder since it never received "Final Approval."

Note: the Cal/OSHA pdf files I linked to are titled "PROPOSED STATE STANDARD" but they are, in fact, the final text approved by the California Office of Administrative Law (OAL) The Low-Voltage Orders were effective May 8, 2008 and the High-Voltage Orders were April 1, 2009 (no Joke). The High Voltage pdf file is the only readily available public version and is so heavily edited my mind is reeling.
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