Hazardous area classification

[global9000]

I'm working on a project in Canada so I am following the CEC guidelines. One of the plants processes that was non-hazardous has been modified and now the area is classified as Class I Zone 2. I have Nema 4X junction boxes containing terminal blocks. According to CEC 18-156(1)(7) boxes, fittings and joints need not be explosion proof except as required by the rules in section 18. Does this mean I can re-use these junction boxes with ordinary terminal blocks?

Also TECK cable is used to feed the junction boxes. TECK cable is not approved for Class I Zone 2 unless marked as approved but ACWU cable is. Isn't ACWU a cheaper and less robust form of TECK cable. Talking to cable suppliers it seems that ACWU or TECK cable should be specifically rated for use in hazardous locations. Why the blanket approval of ACWU for Class I Zone 2?

 

[waross]

My understandind has been;
ACWU90, This is armoured Cable, Wet, Underground.
This is basically AC cable with an added jacket.

Teck cable, In TECK cable rated for hazardous locations, the armour is wound quite tightly around the inner jacket, so as to not allow space for gasses betwen the inner jacket and the armour.
It is fairly easy to remove the outer jacket and armour from standard TECK cable. The jacket and armour may often be removed in sections several feet long, 10 feet or more in some instances.
It is quite difficult to remove the armour from hazardous rated TECK cable. It is often necessary to remove the outer jacket and then twist the armour to increase the diameter before it may be removed. It can be an extra labour issue when estimating work.
respectfully