What is the technical term for the putty that electricians use to seal around service cables where they enter meter boxes, or pass through walls?
- posted
12 years ago
What is the technical term for the putty that electricians use to seal around service cables where they enter meter boxes, or pass through walls?
I've not seen putty used in that situation.
Dust Seal or Duct Seal Compound is the trade designation of the material.
Great Stuff seems to work.
*Duct Seal
It's Duct Seal, or as manufacturers call it, thumbgrade.
We use it only to seal conduits going into hazardous areas. It will prevent a dust explosion from propagating through conduit, at least in theory.
They sell it in all the big box home improvement stores, BUT the actual purchasers are a very specialized group.
The only people who buy much duct seal are airgun shooters. Duct Seal makes an ideal pellet trap, just fill a flat box with it. It absorbs a pellet silently and traps all lead dust. Every once in a while (few thousand rounds) you dig out the pellets and smooth out the duct seal again.
Long ago I talked with an old timer at Johns-Mansville or whatever they were at the time who used to make the stuff. It's basically calcium oxide and grease, made in a big pug mixer in batches of about
1000 pounds at a time. Of course he wouldn't tell me the real recipe.
And who said you never give helpful answers?
Likely you have never even tried it because great stuff isn't UV resistant so it quickly turns yellow and gets brittle. Other than that it looks great on those infomercials.
On the other hand the stuff (duct seal) electricians use is easily applied with your fingers without any mess and stays pliable for a long time.
I have tried it. Six years ago to fill the voids around a new circuit breaker box. It's still there.
In the event it does turn brittle decades from now, who cares? Bricks are brittle. As long as bricks, or Great Stuff, are not under shear stress, brittleness is irrelevant.
Ducseal is one brand - often called DUMDUM. It if fireproof. I think the original stuff had asbestos in it - not sur what is in it now.
Very fireproof. We used it around cadweld mold holes to contain the liquid copper when connecting copper cables to ground rods.
Absolutely relevant for the application. There is a really valid reason why certain methods become standard methods.
Oh, I mostly agree with conventional wisdom. So what is the "standard" method in the instant case?
There is also some stuff called "Coax Seal," available as strips in small quantities used by ham radio operators to seal coaxial fittings out-of-doors. It is really sticky and never seems to harden. You need something like lacquer thinner to get it off! Any good ham radio supply house, or by mail order. Good for small jobs.
/paul W3FIS
You mean you don't bother reading replies to questions that have useful answers? I believe there are at least three posts in this thread that list the time tested and proven product that is ubiquitously used by electricians.
Just wanted to follow up on one of your other great suggestions. We are having a blast using that idea of yours to build shelf hangers out of light gauge wire. Unsuspecting people set a heavy object on the shelf and next thing they are on the floor under a pile of stuff. It is hilarious...
I have never heard it called anything but "duct seal", but lots of products have different names in different areas. The last box I bought was labeled "Duct Seal" (Panduit).
Where a conduit or sleeve goes between areas of different temperature where "condensation is known to be a problem" an _"approved material"_ is required to seal around the wires or cables (300.7-A). The seal prevents warm moist air from circulating to the cold area. Around here, inside the service conduit into a building is always sealed. There are other places where it is appropriate.
"Fire stop" is to maintain the fire rating of a wall or floor, but should work.
Can't imagine protection to a hazardous area wouldn't require a seal-off fitting with appropriate seal material. Can't imagine duct seal being used as a hazardous seal.
Oh I read the replies. It's just that I figured they were, to you, as cockamamie as mine. That's why I asked for your recommendation. I take it from your lack of reply that you don't actually have an idea other than disparaging those of others.
Only if you take pleasure in the misfortunes of others, which, when I think on it...
Never "monkey shit"?
It can be a draft stop but not a fire stop.
You mean this reply I made in this thread:
"On the other hand the stuff (duct seal) electricians use is easily applied with your fingers without any mess and stays pliable for a long time."
Or where I noted in my reply to you that at least 3 others noted the same product:
"I believe there are at least three posts in this thread that list the time tested and proven product that is ubiquitously used by electricians."
Duct seal
John Grabowski
On Thursday, October 13, 2011 at 8:08:36 AM UTC-4, snipped-for-privacy@rochester.rr.com wrote: Helpful thread. Thanks all! Never knew the official name of this very useful stuff!
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