From: clewis@ferret.ocunix.on.ca (Chris Lewis)
Newsgroups: misc.consumers.house
Subject: Re: condensation in breaker box
Keywords: What is going on here?
Date: 23 Jan 93 17:30:29 GMT
Distribution: usa
Organization: Elegant Communications Inc., Ottawa, Canada

In article <8378@tekig7.PEN.TEK.COM> johnst@tekig6.PEN.TEK.COM (John F Stoops) writes:
>I recently discovered condensation in the breaker box for my house.  The
>breaker box is in my garage on an interior wall.  I believe I created this
>problem when I refinished the room on the other side of the garage wall -
>the problem didn't exist before.  I insulated the wall and put plastic 
>sheet around the breaker box.  My thinking was that warm moist air in the 
>house would condense in the cooled breaker box as it leaked from the heated
>house into the unheated garage.  The plastic sheet would provide a vapor barrier
>to the air in the house leaking into the box.  Obviously, I was wrong.  Can
>some of you netters with more experience/insight help me understand what is
>really happening here?  If necessary, I will open the wall from the garage side
>and remove the insulation and plastic sheeting.  

It's a little hard to tell exactly what your situation is, but some
points:

	- bagging the panel is the absolute worst thing you can do.  Even if you
	  don't have air-infiltration from the heated area, you'll still
	  get condensation in an unheated garage.  Even without being bagged.
	  But bagging it makes it FAR worse.
	- You should have normal vapour barrier on the heated side of the
	  insulation in the new living space.
	- A sheet of plastic between the panel and the wall may help. But
	  do NOT enclose the panel.
	- If there are any passages from the panel directly into the house
	  (like a chunk of conduit exiting the back of the panel) they
	  should be sealed with something like silicone.  (this is
	  a common cause of problems with indoor panels - cold air
	  going thru the service's conduit causes condensation inside
	  the panel - our electrical code is quite strict on conduit
	  sealing)

If the vapour barrier is properly placed (warm side) and has no leaks
the refinished room is not likely the problem.

It could be moist air leaks from anywhere - from leaks in the vapour barrier
*elsewhere* than behind the panel, or simply from brief warm bits of
weather - at certain times of the year I get condensation on metal
tools in my garage, and it's 100 feet from the nearest heated structure.

General condensation problems in a garage can be solved by either venting
the garage better, or actively heating it (after insulating/vapour barrier
etc).  My garage (insulated, vapour barriered, unheated, gravel floor)
occasionally has major condensation problems.  By removing the attic hatch
the problem is almost completely eliminated.

I should emphasize that condensation in a breaker box is a serious problem
(up to and including explosions and fire), and should be fixed as quickly
as possible.  Leaving the breaker panel door open with a one or two
high wattage (60-100W) incandescent lights hung close in front of the
opening is a simple but effective short-term solution.
-- 
Chris Lewis; clewis@ferret.ocunix.on.ca; Phone: Canada 613 832-0541
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