Sealing a cable 1

[zandbj]

Hi,
I have the following challenge. I need to seal 3 to 6 mm cables in a 6.5 mm hole. There can be different jacketing materials on the cable PVC, PUR or Low smoke non halogen jackets. The seal has to meet IP65 (dust and water resistant) . be as chemical resistant as possible and should act as strain relief. I'm looking for an adhesive that can do the trick instead of the common rubber washers and mechanical strain relieves.
It should set as quickly as possible. Ones the cable is fixed it's fixed so no need to ever remove it ever again.
Any ideas or leads would be very welcome. I'm thinking like a PUR foam or a Intumescent material but have little experience with these materials and a problem where to start. So all help welcome

 

[MikeHalloran]

I used to work in a place that made natural gas gensets to run on whatever gas came up from oil wells.
The electrical systems were sealed to keep from igniting the gas, which could be anywhere, or not.
The last step in sealing every junction box was pushing a wad of epoxy into the conduit connections around the wires. I think it was a thickened two-part epoxy, mixed in the applicator's hand. It may have been special purpose, certified etc., and intended just for hazardous area service, and expensive. For you, any number of common cut-off-and-knead epoxies might be okay.
Sealing was saved as the last step because it was permanent, and just not possible to adjust to add a wire, etc. I don't know if that would be sufficient strain relief for your purposes.


Mike Halloran
Pembroke Pines, FL, USA

 

[jraef]

You will not get any reasonable strain relief from anything flexible enough to seal unless there is compression involved, meaning no goops. You can get mechanical seals intended for ship bulkheads and firewalls that do this. Roxtec is a big supplier of those, also OZ Gedney / Nelson Fire Stop. The seals can be intumescent or not depending on your need. Roxtec in particular has some very easy to implement options if you have pre-existing conduit penetrations or even concrete cored holes.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[zappedagain]

Icotek is another good brand to look at for an off the shelf solution.

Z

 

[ScottyUK]

jraef, zappedagain - the hole is only 6.5mm diameter.

I like Mike's solution - epoxy barrier seals get a heck of a hold on conductors, to the point where the conductor will snap rather than pull free. The mechanical strength of the seal will depend on the panel thickness as well as the hole diameter.