Strain relief fitting question

[paulga]

The grommet opening is too large for a 12-3awg wire bundled in one jacket. The package does not come with other grommets. Besides multiple layers of heat shrink around the cable, how to seal the opening properly from moisture?

 

[SteveK]

https://www.amazon.com/waterproof-grommet/s?k=waterproof+grommet

 

[paulga]

https://www.amazon.com/waterproof-grommet/s?k=waterproof+grommet

The grommet is inside the 3/4" strain relief fitting, featuring collapsing teeth and an inverting membrane. I didn't see the same grommet in your link.

 

[Nick F]

The whole assembly is called a cable gland. You may have to buy a bigger cable gland. It is possible that the bigger gland might need a bigger hole in the box.

 

[paulga]

The whole assembly is called a cable gland. You may have to buy a bigger cable gland. It is possible that the bigger gland might need a bigger hole in the box.

The strain relief fitting is available in 1/2", 3/4", etc. in home Depot. The 3/4" one screws into the hole on the elec box while 1/2" is too small.

The next size is 1" that would not go in. So I didn't get what you are saying.

Home Depot has a duct seal putty that can seal the hole.

 

[Nick F]

Look at the link that SteveK sent. The Amazon offering has many different sizes - one of these will work for sure. Each size has a diameter that it matches. Measure the outside diameter of your cable.

However -
it is possible that you might get your cable into the existing fitting. Disassemble the fitting (as in your photo), Lubricate the rubber grommet and your cable with dish liquid and stretch the grommet over your cable. Then reassemble the gland. Dont forget to insert the cable through the nut and other plastic piece before inserting into the grommet.

 

[paulga]

Look at the link that SteveK sent. The Amazon offering has many different sizes - one of these will work for sure. Each size has a diameter that it matches. Measure the outside diameter of your cable.

However -
it is possible that you might get your cable into the existing fitting. Disassemble the fitting (as in your photo), Lubricate the rubber grommet and your cable with dish liquid and stretch the grommet over your cable. Then reassemble the gland. Dont forget to insert the cable through the nut and other plastic piece before inserting into the grommet.

Wires measures 0.18" each, 3 wires is 0.54". 3/4" strain relief has a grommet of 0.75", it's too large for the wires. After the wires going through there will be some gap around the wire. Why is dish detergent needed here?

 

[Bmarler]

Usually those cord grips from Home Depot have a pretty big range of adjustment. Have you tried tightening it up to see?
Other question, what type of cable goes through this? If it’s flat boat cable there will always be some gaps.
There are special cord grips with oval shaped openings for flat cable. Really though, if the grip tightens up enough to keep the cable from moving, but still has some air gaps, it’s ok. If needed for protection from water spray, use some type of sealant from a tube.

 

[paulga]

Usually those cord grips from Home Depot have a pretty big range of adjustment. Have you tried tightening it up to see?
Other question, what type of cable goes through this? If it’s flat boat cable there will always be some gaps.
There are special cord grips with oval shaped openings for flat cable. Really though, if the grip tightens up enough to keep the cable from moving, but still has some air gaps, it’s ok. If needed for protection from water spray, use some type of sealant from a tube.

it's for 3 ac wires each 12g. The wires will be in a heat shrink making a triangular shape.
the home depot agent yesterday also showed me a duct seal putty, saying it's not necessary for inside application.

 

[Bmarler]

it's for 3 ac wires each 12g. The wires will be in a heat shrink making a triangular shape.
the home depot agent yesterday also showed me a duct seal putty, saying it's not necessary for inside application.

Agree, for inside application all you need is to secure the wires so they don’t move around. If the gland won’t tighten up and hold the wires, just put a couple of wraps of wither silicone tape or rubber splicing tape around them. Those build thickness quickly so only a few wraps are needed.

 

[Nick F]

Sorry Paulga - just re-read your OP and see I had it backwards.

As others have said, further tightening of the nut crushes the grommet to a smaller diameter and may be all that is required in your case.