From: John De Armond
Subject: Re: Alternative enclosures
Date: Sun, 23 Apr 2006 03:25:21 -0400
On Fri, 21 Apr 2006 12:00:53 GMT, Ecnerwal
>I'm (finally) getting to fish or cut bait point (converting research and
>cash into a system and no cash).
>One of the things that drives me nuts is the price of accessory "stuff"
>required to "properly enclose everything to US NEC". I do wish to be NEC
>compliant and generally safe -
Those two things have nothing to do with each other. Having been
involved in trying to remove some of the insanity from Part 600, I'm
familiar with how that putrid thing called the NEC arrived at where it
Twenty years ago the NEC WAS a useful safety guide. Coincidentally,
one could also lift it with one hand! Now it's little more than
something to guarantee markets for apparatus makers. The holy grail
for any manufacturer employee NEC committee member is to get his
company's product written into the code, either explicitly by name or
by reference to proprietary, perhaps patented technology.
>So, if the whole business is installed in a nice grounded rack enclosure
>which requires tools to open, with the breakers and disconnects sticking
>out, at the proper height (operating handles less than 78 inches from
>the floor) and requiring less than 6 motions of the hand to shut down
>completely - should there be any problem using general-purpose equipment
>enclosures rather than special-purpose enclosures?
Yes, of course. That's how its done in areas like the power utility
industry where the NEC isn't allowed to intrude. Also in most
industrial settings where as a practical matter, the enforcement nazis
don't have access.
Electrical safety is mostly what I call "enlightened common sense".
Enlightened in that you need to know the perils in order to exorcize
common sense. A pre-'85 edition of the NEC is a good place to start.
As is thinking through the purpose and goal of a specification and
then achieving it without all the overhead.
For example, to mount neon channel letters, I could go out and buy a
listed wireway made of metal heavy enough to constrain conductors
carrying tens of thousands of amps of fault current - or I could
fabricate it in my shop from sheet metal only thick enough to hold up
the letters. Perfectly adequate because at most, the sign is
connected to a 20 amp breaker. Guess which one I do.