class 1 cable end sealing

[wyo1]

In regards to 515.10 d 2, which states that a multiconductor shielded cable need not require the cover removed when sealed in a seal off and may be treated as a single conductor. It also says that the cable end must be sealed in the enclosure.

How does one legally go about sealing a cable end?

 

[dicklaxt]

I ran across this years ago in a Class 1,Div.1 area involving an Instrument J box and termination of a 36 pair cable.

The cable was routed thru an EXP Gland into the box and then each individual pair had a slip on heat shrink sleeve installed over them with some sealing goop inside,these were then heated with a heat gun shrinking the sleeve and melting the goop at the same time around the individual pairs ,then this whole mess had a wrap on/lace up heavy heat shrink boot,this inturn also had the goop, if I remember correctly the finished requirement was about 20" long. It was made by Ray Chem I believe but don't quote me on that it was about 30 years ago.

A telephone call to the cable manufacturer brought an ensuing letter into play saying that the interstices of the cable had a gas block inherant to the manufacturing process stopping migration of gases,this when presented to the client relaxed that requirement of sealing the cable end. We only did that one. It must have taken at least 2 hours for that and then the hardwire terms on top of that,plus the box size had to be increased.

It might be worth a phone con with your cable guy/client.

If you are stuck with that requirement,and if I remember corectly it could have been sealed at the non hazardous as well as either option of sealing location the end would have been legal as the outer jacket was impervious to gas migration.
dick

 

[dicklaxt]

I don't have a Code Book handy but if you are talking about a gas block then the above or something similar is probably the answer. If you are talking only about a moisture seal then a heat shinkable breakout boot is what you need.........see 3M products catalog

dick

 

[weressl]

I ran across this years ago in a Class 1,Div.1 area involving an Instrument J box and termination of a 36 pair cable.

The cable was routed thru an EXP Gland into the box and then each individual pair had a slip on heat shrink sleeve installed over them with some sealing goop inside,these were then heated with a heat gun shrinking the sleeve and melting the goop at the same time around the individual pairs ,then this whole mess had a wrap on/lace up heavy heat shrink boot,this inturn also had the goop, if I remember correctly the finished requirement was about 20" long. It was made by Ray Chem I believe but don't quote me on that it was about 30 years ago.

A telephone call to the cable manufacturer brought an ensuing letter into play saying that the interstices of the cable had a gas block inherant to the manufacturing process stopping migration of gases,this when presented to the client relaxed that requirement of sealing the cable end. We only did that one. It must have taken at least 2 hours for that and then the hardwire terms on top of that,plus the box size had to be increased.

It might be worth a phone con with your cable guy/client.

If you are stuck with that requirement,and if I remember corectly it could have been sealed at the non hazardous as well as either option of sealing location the end would have been legal as the outer jacket was impervious to gas migration.
dick

Couple of points to think about.

Gas will only 'migrate' if there is sufficient differential pressure between the two points.
Gas will migrate in inverse proportion of the pressure vs the cable length. Eg. any given cable type will need increased pressure differential for longer length to 'pass gas' .
XP seals are not necessarily exhibit chemical resistance against the chemicals encountered and they effectiveness may be compromised by those. It should be of special concern in the case of devices and insatruemnts with a single seal between the process material and the wiring termination point.

 

[bobgorno]

Be careful how you read the exceptions on shielded cables. you still have to remove the jacket or covering, you don't have to remove the shileding material or disturb twisted pairs.


There are various listed cable connectors out there that utilize an epoxy sealing compound.

See attached for an idea on how to seal a cable end.