Re: [APD] Re: Problem with MH light -- oir - Roasted Nuts but No Meal in Flight

["S. Hieber" <shieber at yahoo_com>]

Bill Wicher's advice is good stuff.

You might contact Hamilton and see what they have to say
about the lamp -- if certain models indeed had a heat
problem, then a forthcoming employee might concede, perhaps
off the record, that certain models had a problem with
heat.

With heat, it's not just temperature but duration that
counts.  A *relatively* low heat can ruin insulation if it
persists for a long time. Whereas insulation might fail
very quickly at 150 F, it might take years at 120 F.

If you aren't going to do a ballast replacement, or even if
you do, consider replacing all the wiring with hi-temp
insulation wiring. Sounds like the wiring insulation gave
way after overheating, hardening and cracking. Wire
insulation materials tend to become conductive once they
burn so sparking from cracked insulation can lead to a
greater failure of the insulation, etc.

Possibly, the wire nuts were the culprits that gave way to
heat. Or possibly one of them was loose enough that over
time it eventually allowed a spark that lead to worse
failure. 

But a spark (to ground) ought to trip the GFCI. But the
GFCI didn't trip until after the smoking -- so I'd put my
money on overheated/burning wire insulation.

A box of wire nuts ought to have a max temperature rating
marked on it -- it will be surprisingly less than you might
imagine -- lower than a bad day in Death Valley.

Sooooo--you might try rewiring with the existing
electronics -- maybe try the old bulb on it first. If
everything works, fine, the insulation was the failure.
Otherwise, or to possibly save time, replace parts along
with the wires and nuts.

Scott H.

--- Steven Pituch <spituch at ev1_net> wrote:

> Ok the transformer and capacitor look good.  I removed
> the ceramic socket
> from the pendant.  Man, this thing is heavy duty!  When I
> removed the socket
> by pulling it down and pushing the cable into the top of
> the pendant, a
> whole bunch of charred pieces of plastic fell out of the
> pendant. The wire
> nut connectors to the socket were charred.  The wires
> obviously shorted out
> after the twist connectors disintegrated.
> 
> This pendant is five years old.  It must be extremely hot
> at the top of the
> socket.  The two short pigtail wires from the socket are
> fabric covered,
> probably some high temperature ceramic fiber.  However,
> the wires from the
> cable don't look anything special.  Their insulation is
> gone, just turned to
> powder.  I wonder if I need some special hi-temp wire
> nuts or the normal
> kind will be OK.   In either event I should probably
> rewire these every
> couple of years since the insulation on the cable is
> bound to deteriorate
> again.
> 
> This is could to happen to all Hamilton pendants unless
> the design was
> modified after 1998.


=====
S. Hieber

 - - - - - - - - - -
Amano Returns! 
at the AGA 2004 Annual Convention -- Nov -- Baltimore

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