2008NEC article 501.15(E)(1) exception 2

[charles hammond]

Raychem has made an approved product (specifically CBK-5T for instance) that is accepted by our local AHJ to use as a gas/vapor blocking material. I have not been able to find a distributor for nor an equal replacement product. any ideas?

 

[rbalex]

I'm assuming these are multiconductor instrument cables in conduit. You might consider this 3M product. Another alternative is to use this product with a 50% tape overlap lay and then shrinkfit a tube over it to force the mastic into the interstices. You may want to check out this thread too.

Side note: I suggested Raychem market the CBK as a "cable seal" over 25 years ago. Technically, the NEC never specifically recognized it, but AHJ's that understood hazardous locations did.