Grommet?

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Alwayslearningelec

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Need the geniuses opinion here( I do mean that). Need to run a cable(about 250mil OD..about size #6 THHN) through a 1" KO. The opening has to have some sort of waterproof grommet or bushing. Thing is we can't get/reach to the other side of the KO so it has to be something that's pushed into the hole. Any suggestions, thanks.
 
How watertight does this need to be?

When you say you cant reach the other side, clearly there has to be some access, because the cable needs to go somewhere? But it might be a very long reach, correct?

Could you use something for mechanical support (eg. a push in bushing) and something else for water sealing (eg. electrical RTV)?

-Jon
 
winnie said:
How watertight does this need to be?
Click to expand...

Hmmm. When I read waterproof I was not thinking weathertight. I was thinking he didn't want the bushing to get ruined by getting wet.

A big glob of silicon may make it weathertight, but I don't know for sure. Probably some rule against it.
 
In plumbing there is something called a 'test plug', essentially a rubber ring or bladder that gets expanded by being squeezed from the ends. Specifically designed to be installed from the end of a pipe with no access to the inside, water tight under pressure. Some have a 'bypass', a tube that you can use to connect to something like a pressure gauge.

I think this gets pretty close to what is being looked for, but not quite.....
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-Jon
 
It may be hard to find a connector like that for 0.25" O.D. cable that takes a knockout as large as 1", because that would be a larger knockout than is necessary for a such a product.
There are however snap-in cable gland connectors for 0.25" cable that go into 1/2" knockouts and meet the IP68 ingress spec :





www.standardelectricsupply.com

Thomas & Betts NPG-0501B Quick-Connect Cable Gland | Standard Electric Supply Co.

<p>Thomas & Betts NPG-0501B Quick-Connect Cable Gland</p><p>T&B Cable Gland, Quick Connect, Series: NPG, 1/2 in, Cable Openings: 6 to 12 mm, Non-Armored/Portable/Tray Cable, NPT, Nylon, Black, -20 to 100 deg C, 1.201 in Dia</p><p><strong>Additional Description:</strong> TB -NPG-0501B QUICK CONN...
www.standardelectricsupply.com www.standardelectricsupply.com
 
Is the enclosure thick enough to thread, and then use a reducing bushing to get down to 1/2" and use a gland-type clamp?

1599003143909.png 1599003175378.png 1599003194389.png
 
I don't know why there isn't something as simple as a rubber bushing like this that would work? Except for the metal, just a hole that would squeeze around the conductors.
 

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If the steel is 1/4" thick, then you can use a tool called a tap to cut threads in it, and then screw in a suitable sealing device.

But afaik sealing devices will all protrude far more than the 1/4" you specify.

The diaphragm grommet is likely the closest solution, but you might need something custom made out of suitable materials rather than the random thing I found on Amazon
 
winnie said:
If the steel is 1/4" thick, then you can use a tool called a tap to cut threads in it, and then screw in a suitable sealing device.

But afaik sealing devices will all protrude far more than the 1/4" you specify.
Click to expand...
A locknut can be used to limit the intrusion of a reducing bushing.
 
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