UL Rating for millivolt sensors

[nospark]

Has anyone ever heard that sensors for building management systems need to be UL approved, per NEC requirements?

We have an electrical inspector, that has failed a mechanical control systems because a temperature sensor mounted in ductwork is not UL approved. No manufacturer has ever made a UL approved sensor for this application. He states it's a NEC requirement, but I can't find it anywhere.

If anyone has a clue where and how this inspector came to the conclusion, please let me know.

Thanks

 

[roger]

Re: UL Rating for millivolt sensors

With the exception of "specific items" the "NEC" doesn't care.

90.4 The authority having jurisdiction for enforcement of of the Code has the responsibility for making interpretations of the rules, for deciding on the approval of equipment and materials,...

This specifically allows an inspector to approve an installation on his judgement, regardless of the absence of a listing as long as the items in the installation are not specificaly required to be listed in an article.

Now 90.7, Note the second and third words, Specific items, these items are stated in the applicable articles, and relieves the AHJ of having to judge an item safe.


If the equipment has been listed by a qualified electrical testing laboratory that is recognized as having the facilities described above ...


This would also relieve the inspector of this decision if a "non specific item" is listed.

With the exception of the items called for to be listed in the specific articles, there is no mandatory rule that requires all items to be third party tested.

With all that said, if the sensors are part of an assembly there may be a UL listing covering the assembly as a whole.

Roger

[ May 17, 2004, 12:49 PM: Message edited by: roger ]

 

[tom baker]

Re: UL Rating for millivolt sensors

The basis for approval is 90.4 The AHJ can ccept unlisted (its listed, not approved) products, but the primary basis is listing and labeling.
If there are no listed products available then the inspector would make the determination.