maintaining UL Type 12

[garydownhere]

It's easy to purchase a Type 12 enclosure and yet another to install UL Type 12 conduit fittings. There's "Rain Tight", "Liquid Tight" & Hazardous location fittings (just to name a few). We have UL Type 4 Myers Hubs but the UL Field Specialist would not accept them since they don't say Type 12. Is there a way to maintain UL Type 12? We have been achieving NEMA 12 but when UL inspects our panel, we must derate the enclosure to UL Type 1. UL508A 19.4 gives me the choice of filling the cabinet holes with Type 12 equipment or derating to Type 5 or Type 1.

 

[jraef]

A) You are required to use Type 12 (or greater) listed penetration methods. One such method is to use UL listed sealing conduit hubs.

B) Another is to use "sealing bushings" on the end of a Rigid or IMC conduit. If you use liquid tight flexible conduit, you must use the sealing type fittings. All of the above have an oil and water tight O-ring or gasket that seals up against the enclosure wall and the conduit, re-establishing the type 12 integrity. There is no Type 12 method for EMT

C) Your inspector who says a Type 4 hub does not meet type 12 is a boob. But even so, "Myers" hubs ARE UL listed as type 2, 3, 3R, 4, 4X and 12, as are every other brand I have ever seen. The only difference between a type 12 and a type 4 gasket would technically be that type 12 needs to be oil resistant, but it makes no sense for manufacturers to make 2 different types of gasket, they only use one.

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[djs]

Some UL inspectors require the type rating to be marked either on the device, the carton or as an insert in the box. Catalog pages will not do. Also some devices are only rated type 4 and are not rated also as type 13.

The solution is to find fittings that are rated type 12. And make sure the box is marked as such.