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Posted by Ecnerwal on April 21, 2006, 12:00 pm
 



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 - I just find the pricing on enclosures for
that purpose somewhat high. I'm looking at the Outback stuff at present,
and all the "doo dads" (PSDC, DCA, ACA, PSAC) to be able to hang things
on the wall so everyone can admire them run several hundred dollars
(well over a thousand, but that would be including some internal
components which will be needed anyway, so call it several hundred).

Some part of my research found a comment that the various add-on parts
were not required if the whole thing was installed in an "approved
enclosure". Now, as it happens, I've been an inveterate scrounge for
decades, and I have stored away a variety of 19 inch (50cm) electronic
equipment racks, some of which either are or can be fully enclosed.

Considering the various uses to which these rack systems were put when
they were in service, running a household power system would be rather
mundane. On the other hand, considering the age of some of them and the
fact that they are not all stored for easy access, I cannot be sure that
"approval stickers or labels" still are attached to them until I dig
them out of storage. Given the work I was doing at the time I rescued
these from the trash stream, I have full confidence that I can safely
and effectively wire things up inside, and I note that the size of the
outback inverters is what I would call "conveniently rack-mountable".

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?

--
Cats, coffee, chocolate...vices to live by

Posted by sylvan butler on April 21, 2006, 5:19 pm
 


wrote:

NEC is (for the most part) targetted at "generally safe".  The problem
is, "NEC compliant" is a judgement call.

Will you be pulling a permit and getting the work inspected?  If so, the
inspector is the one who will be making that judgment call, and as such,
you should ask that inspector.

If you won't be pulling a permit, you need to do more research until you
are comfortable making your own judgement call.


Yup.  "approved by whom?" is the question you should be asking
yourself...


I doubt they are.


In my opinion, no.  But my opinion is worth less than you paid for it!

sdb

--
Wanted:  Omnibook 800 & accessories, cheap, working or not
sdbuse1 on mailhost bigfoot.com

Posted by Pete C. on April 21, 2006, 5:52 pm
 

Ecnerwal wrote:

19" equipment racks are great for servers and network gear (and video,
audio, etc.), but not real good for power stuff. Accessibility and
working clearances tend to be inadequate for power stuff. I've also
never seen an equipment rack with any particular approval stickers
unless it had an integrated power distribution system.

I think you need to review the NEC bits about "accessible to qualified
persons". Mounting your equipment on a normal backboard with a locked
cage guarding everything but the disconnects would probably meet that
definition acceptably. Plexiglas guards mounted on standoffs to shield
equipment with exposed terminals from probing fingers would also likely
be acceptable.

The idea is not so much to have everything in a grounded steel box as
much as to guard against casual contact with live terminals.

Another thing to remember is that the basic steel pull boxes are pretty
cheap in smaller sizes, up to 12" x 12" x 6" or so. Don't go by the
prices you see in Home Depot or Lowe's, these slow moving items are not
competitively prices at such places. I recently checked prices and a
6x6x4 at HD / L's was several dollars more than a 10x12x4 at an
electrical supplier. 1/2" threaded "T" bodies were $+ at HD / L's and
$.50 at the electrical supplier.

Pete C.

Posted by SQLit on April 22, 2006, 12:12 am
 



You have a couple of issues here, one is the NEC. The other is U.L. in the
olden days, before "Series ratings". Manufactures like the one I work for
put distribution panels and switches into all sorts of enclosures, AL, SS,
and sheet metal.
Along came U.L. in the mid to late 70's and now it much worse. Our U.L.
inspector spends 2-3 hours every couple of months checking and evaluating
what we are doing. The owner is a fanatic about the paper work and all they
found today was we needed to add 100K to a single label.
(not bad at all). Custom stuff today must be tested as a unit. No more
throwing a bunch of listed equipment together  and selling it.  We decline
to do it any more.

OF course if your in an area or do not give a d _ _ _  then connect away. Be
forewarned if there is a problem your going to be on the hook, insurance
companies tend to run away from Hodge-podged electrical installations now
days.

Short answer is, get the parts and assemble it your self and have a lot of
wall space.



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