On Tue, 25 Nov 2008 20:31:18 -0500, Joseph Gwinn
wrote:

In article ,
jk wrote:

Joseph Gwinn wrote:


At that voltage level, you are not allowed to use directly activated
switches, and must instead use contactors in grounded metal boxes, and
so on. I'm sure we will hear from the electricians on the group about
that.

Completely not the case.

You can use switches up to any level, yes,direct manually actuated
ones.

They do get BIG as the voltage gets higher, Size of a hallway closet
in the case of 12 and 21 KV.
jk

I didn't qualify it enough. I'm not talking about substation switches.
I heard this from an electrician in Rhode Island.

Perhaps he was talking about some requirement other than the NEC. For
example, I built equipment for GE's steam turbine division and they
had some in-house rules that were considerably stricter than the NEC.
The one that comes to mind was a limit of 240V in flexible cords.


Another poster mentioned arcs blowing the cover off so one should stand
off to one side. Sounds like a job for a contactor in a steel box.

I've seen it happen on a 480V motor starter. Pretty exciting.

--
Ned Simmons