Area class

[bean9677]

I what to know if a tray cable or CLX needs a seal or sealing fitting on either end or not at all. Here is what I have. A motor in a Div. 2 location fed with tray cable or CLX and goes directly to the substation, that is in a unclassified area. Do I need any type of seal on the cable. I know the motor does not need a seal. Are the cables capable of transmitting gases/vapors?

 

[rbalex]

This is easier to explain from the 2011 and earlier NECs. See Section 501.15(E)(3).

With the 2014 NEC you have to carefully parse both Sections 501.15(E)(1) and (3).

The UL White Book will tell you Type TC and Type MC with a "corrugated metallic sheath" have "a gas/vaportight continuous sheath". It won't tell you if they are "capable of transmitting gases or vapors through the cable core" or not so you may as well assume they can and let Section 501.15(E)(3) apply.

There is very important "not" in Section 501.15(E)(3) [2011NEC and earlier]. It is absent in in 2014. The entire Section 501.15 has been rewritten to clean up grammar and such. The meaning hasn't changed but is why Section 501.15(E)(1) needs to be parsed carefully. Gotta love English ambiguity and unintended consequences.

Basically IF sealing isn't required by Section 501.15(E)(1) because its an explosionproof enclosure, THEN it isn't required by Section 501.15(E)(3) "... unless the cable is attached to process equipment or device that may cause a pressure in excess of 1500 pascals ..."

NOTE: The first sentence of Section 501.15(E)(1) [2014] says WHEN a cable is required to be sealed, the rest of the Section tells HOW.