Class 1 Division 1 cable seals

[sparky7746]

Does anyone know of an "approved means" for sealing cable ends per 501.15 (D)(2) exception?

 

[rbalex]

It will depend on what your AHJ believes is acceptable. If it requires a listed or labeled product you may as well return to the main rule.

Otherwise, there are a few alternate means that should be suitable. [See Section 500.8(A)] The most common is a heat-shrink tube with an internal mastic that melts around the conductors. [I know that works].

You should also become familiar with Section 501.15 FPN/IN No.1 and it's cross-referenced Sections. This explains the limits of what you [and your AHJ] should expect a "seal" to actually do.

 

[sparky7746]

Any idea why this rule does not apply to Class 1 Division 2?

Would I need a cable seal (cable in conduit) going from a C1 D2 control enclosure, rated for the environment, sheet metal with hinged gasketed cover to a non rated area?

501.15 (E)(3) says cables capable of transmitting gasses shall be sealed as in 501.15 (E)(1) which says the cable is required to be sealed if the enclosure is required to be explosionproof. I don't believe my C1 D2 listed sheet metal control panel is explosionproof, so do I need a cable seal there?

How about my boundary to unclassified? This does not appear to be mentioned specifically as it is in 501.15 (D)(2) for C1 D1.

Thanks for the advice.

 

[rbalex]

You are under the 2014 NEC and Section 501.15(E) has been wordsmithed in the last few Code editions to make it as confusing as possible. For Division 2, you must parse 501.15(E)(1) very carefully to even begin to understand the rest of the Section. If it weren't for the cross-reference 501.15 IN No.1, you could forget about 501.15 (E)(2) altogether. It only applies to Type MI cable which has its own specific termination rules.

In Division 2, essentially, if the enclosure is required to be explosionproof then you do actually treat it as if it were in Division 1 and seal it for the purposes of enclosure integrity.

For all practical purposes, the cable itself is treated as a single conductor and does not have to be modified at the boundary if it is sealed at the enclosure for either Division 1 or 2. Under 501.15 (E)(3) it isn't required to be modified for Division 2/unclassified boundaries either.

 

[sparky7746]

So if the enclosure is not required to be explosionproof, and the other end of the cable is in an unclassified area, it does not need to be sealed at the enclosure, the seal off at the boundary or the end in the unclassified area?

 

[rbalex]

So if the enclosure is not required to be explosionproof, and the other end of the cable is in an unclassified area, it does not need to be sealed at the enclosure, the seal off at the boundary or the end in the unclassified area?

That is essentially correct for multiconductor cables with "...a gas/vaportight continuous sheath..." . [Such as Type TC] In fact, if the Division 2 enclosure wasn't required to be explosionproof, it wouldn't matter if the other end were unclassified or not.

Most Division 2/unclassified boundaries seals aren't necessary in the first place; that's why there are so many exceptions in Section 501.15(B)(2) for conduits. NOTE: While they may not actually be necessary, they may still be required in some cases - especially for installations under Articles 511 to 516.