cable in conduit cable end seals

[rbalex]

im just finding normal heat shrink, do you use standard heat shrink and melt them together? i took it there was something designed specifically for the use

Try 3M EPS-300.

 

[Wire-Smith]

Try 3M EPS-300.

thanks, hadn't thought of that. i would guess those are water tight so probably pretty good. you probably don't run your tape shield out of one of those holes do u? i wouldn't think that would seal.

have you ever used tsc? works good.

 

[Wire-Smith]

Bob
.I also recall, MI cable - which is rarely used for power applications - is considered to be the only true gas/vapor blocked cable available.

we sometimes use a cable that has a sheath that is molded around the conductors which falls under that, i think uf is like that ain't it?

 

[rbalex]

we sometimes use a cable that has a sheath that is molded around the conductors which falls under that, i think uf is like that ain't it?

MMMMMmmmmmm…. not too likely. For the moment UL won't even certify that Type UF (Art 340) even has a "gas/vaportight continuous sheath" although it probably does. But, for the record, See Section 340.12(7).

 

[Wire-Smith]

MMMMMmmmmmm…. not too likely. For the moment UL won't even certify that Type UF (Art 340) even has a "gas/vaportight continuous sheath" although it probably does. But, for the record, See Section 340.12(7).

i don't believe UF would be certified for that i was just using that as a reference for the molded sheath. i should've been more clear. i have seen cables that say incapable of transmitting on spec sheets. i was asking if uf had molded sheath i think it does, i don't remember for sure though, i barely ever see it

 

[rbalex]

i don't believe UF would be certified for that i was just using that as a reference for the molded sheath. i should've been more clear. i have seen cables that say incapable of transmitting on spec sheets. i was asking if uf had molded sheath i think it does, i don't remember for sure though, i barely ever see it

As of right now, UL does not have a standard to certify any non-MI cable construction to be incapable of transmitting gases or vapors through the core. This is primarily because the MI fittings listed for the location already seal it. [Section 501.10(A)(1)(b)] So what you have seen in "spec sheets" is essentially marketing material. Get a copy of the UL White Book and compare a manufacturer's sales literature against the UL Category Code. You can also do this with the UL Online Certification Directory.

You should still have a copy of the White Book anyway. It has a wealth of application material, it's free and basically a good start for checking conformance with Section 110.3(B). It also has information beyond the UL Online Certification Directory.
​

 

[Wire-Smith]

As of right now, UL does not have a standard to certify any non-MI cable construction to be incapable of transmitting gases or vapors through the core. This is primarily because the MI fittings listed for the location already seal it. [Section 501.10(A)(1)(b)] So what you have seen in "spec sheets" is essentially marketing material. Get a copy of the UL White Book and compare a manufacturer's sales literature against the UL Category Code. You can also do this with the UL Online Certification Directory.

You should still have a copy of the White Book anyway. It has a wealth of application material, it's free and basically a good start for checking conformance with Section 110.3(B). It also has information beyond the UL Online Certification Directory.
​

you probably won't believe me but i actually have a white book. i don't have my code book on me right now though, does that cable have to be listed as incapable of transmitting gases? i will look on free access right now but i don't trust myself coming to conclusion by looking on there, it just takes too long to flip back and forth

501.15(D)(3)

is there somewhere that requires the listing



thanks for the ul online directory, i didn't know about that

 

[rbalex]

you probably won't believe me but i actually have a white book. i don't have my code book on me right now though, does that cable have to be listed as incapable of transmitting gases? i will look on free access right now but i don't trust myself coming to conclusion by looking on there, it just takes too long to flip back and forth

501.15(D)(3)

is there somewhere that requires the listing



thanks for the ul online directory, i didn't know about that

As I mentioned before, several cable constructions are capable of passing the "leak test" [[200 cm3/hr (0.007 ft~/hr) of air at a pressure of 1500 pascals (6 in. of water)] from length alone. However, any differential pressure even marginally above that makes an installation immediately suspect. As it presently stands, neither UL nor any reputable manufacturer has a verifiable documented standard for consistently testing gas blocking under all installation conditions. There are just too many variables to consider.

 

[nhee2]

BTW, the insulation never needs to be removed, only the jacket and/or sheath. In fact, the cement type sealing material is slightly conductive.

Agreed - I intended to type 'jacket', not 'insulation'.

Thanks

 

[Wire-Smith]

As I mentioned before, several cable constructions are capable of passing the "leak test" [[200 cm3/hr (0.007 ft~/hr) of air at a pressure of 1500 pascals (6 in. of water)] from length alone. However, any differential pressure even marginally above that makes an installation immediately suspect. As it presently stands, neither UL nor any reputable manufacturer has a verifiable documented standard for consistently testing gas blocking under all installation conditions. There are just too many variables to consider.

i didn't think non-process seals were required to hold pressure. once again i don't have my code book with me, sorry.

As of right now, UL does not have a standard to certify any non-MI cable construction to be incapable of transmitting gases or vapors through the core. This is primarily because the MI fittings listed for the location already seal it. [Section 501.10(A)(1)(b)] So what you have seen in "spec sheets" is essentially marketing material.

i also don't think the cable has to be listed for that, do you?

all i am talking about is non process seals by the way, just standard c1 d1.


thanks

 

[Wire-Smith]

i see testing laboratories as important and needed, but honestly i don't think they test things we use for as many scenarios that there actually used for in the field (and i mean listed use's). did any of you happen to catch the first article for a series on the residential circuit breaker testing? i think it was in ec&m or electrical contractor magazine this last issue.

 

[rbalex]

i didn't think non-process seals were required to hold pressure. once again i don't have my code book with me, sorry.




i also don't think the cable has to be listed for that, do you?

all i am talking about is non process seals by the way, just standard c1 d1.


thanks

Well get your copy of the NEC or look it up here for the cost of registering with the NFPA. You don’t have to become a member.

Even non-process seals have a pressure requirement. See Section 501.15(E)(2) and read it carefully.

You are rapidly approaching my minimum consultant fee.

 

[Wire-Smith]

Well get your copy of the NEC or look it up here for the cost of registering with the NFPA. You don’t have to become a member.

Even non-process seals have a pressure requirement. See Section 501.15(E)(2) and read it carefully.

You are rapidly approaching my minimum consultant fee.

this is what i'm referring to

501.15 informational note 1 paraphrased- seals are not intended to prevent the passage of liquids, gases or vapors at a continuous pressure. even at pressure of just a few inches of water there may be a slow passage of gas


informational note 2 paraphrased -gas can pass through interstices between conductor strands of normal wire


6" of water is nothing = 0.216547 psi

a normal building usually naturally has more pressure difference than that


i use free access, but i don't make determination's off of it because i can't look through it very quickly


i take it you don't believe the cable has to be listed for that (i asked you twice), but you know the code better than me and i would appreciate a clear answer, but i understand if i've bothered you too much already.



thanks

 

[rbalex]

A product is listed according to the applicable tests in its product standards.

As of this moment, no cable is tested for gas blocking and therefore cannot be certified for that feature. You can however, suggest to the various product standard promulgating organizations that such a feature be certified. You might be surprised at how receptive they would be to such a suggestion. UL has been trying to have GP motor listing a requirement since before I was in the businesses.

 

[MRKN]

My understanding is the cable manufacturer's have no incentive to pay for a listing and create a new product since they see no market. There are other solutions customers end up using.

 

[Wire-Smith]

My understanding is the cable manufacturer's have no incentive to pay for a listing and create a new product since they see no market. There are other solutions customers end up using.

i think that as well, i don't think its required by nec to be listed so whats the point and in my opinion like others commented on earlier most normal cables at a certain length can produce that level of seal. one of these days i will test a cable myself with some homemade stuff, i'll post the results

 

[MRKN]

It would be required by the NEC to be listed to that affect. I would not proceed with construction assuming the AHJ would interpret otherwise, it is a big risk for the project.

 

[Wire-Smith]

It would be required by the NEC to be listed to that affect. I would not proceed with construction assuming the AHJ would interpret otherwise, it is a big risk for the project.

do you have a code reference for it having to be listed for that?

i'm not doing that by the way. its easy enough to seal

i could likely actually pressure test(i think it would pass, might not though) the cable right in front of the AHJ

 

[rbalex]

I was involved in the early stages of developing Sections 501.15 (D) and (E). It was my suggestion to API to Propose what became MC-HL that set the wheels rolling for a variety of cable applications. Sealing cables was always murky at the time. Depending on who is interpreting it, it may still be.

You would be surprised how many cable manufactures at the time were indeed interested in developing a standard for gas blocked cable. As I said, they dropped it because UL and the manufacturers couldn’t determine a suitable test that could be consistently applied in general.

EDIT ADD: As for a Code reference if you were attempting to apply one of the gas blocked Sections it would fall under Section 110.3(B).

 

[Wire-Smith]

I was involved in the early stages of developing Sections 501.15 (D) and (E). It was my suggestion to API to Propose what became MC-HL that set the wheels rolling for a variety of cable applications. Sealing cables was always murky at the time. Depending on who is interpreting it, it may still be.

You would be surprised how many cable manufactures at the time were indeed interested in developing a standard for gas blocked cable. As I said, they dropped it because UL and the manufacturers couldn’t determine a suitable test that could be consistently applied in general.

EDIT ADD: As for a Code reference if you were attempting to apply one of the gas blocked Sections it would fall under Section 110.3(B).

"used in accordance with instructions included"

i interpret this as saying you cannot violate the instructions, and in no-way do the instructions hint at not allowing the practice. i don't believe this means you can only use it for the exact application in the instructions. in no way am i defying the instructions, the instructions tell you how to use it in a seal off, it does not say you cannot use it without a seal off, it may say it is only rated for use in seal off but that is not saying you have to use it in a seal off