Why can't I find a *Listed* Duct Temperature Sensor

Status
Not open for further replies.
A

AtTheKeyboard

Member
Location
Colorado
Is there any chance someone can help me find a code exception, or some other reason why I can't find a *Listed* Duct Temperature Sensor commercially available?

The following item was submitted, and was returned, as was not listed. This resistor is supplied/monitored by a digital control unit, which is supplied by a Class 2 power source. Am I correct that this must be a listed product, despite being on a Class 2 power system?


As the Contractor was revising the submission, they noted that they couldn't find a listed product. From my follow-up check, I too am not finding any indications of listing, including from some larger/familiar brands, including Siemens and Johnson Controls. I see indications of specification compliance, mentions of NEMA enclosure ratings, EMC compliance, and expected technical terms - but not a listing.


Is it generally accepted that these devices do not need to be NRTL-listed? Is there a reason why?
 
I suspect it's because the hardware connection that feeds this has both limited voltage and current, avoiding both a shock and a fire hazard. - Just hoping someone has seen something more formal in the past - thanks!
 
Last edited:
Is there any chance someone can help me find a code exception, or some other reason why I can't find a *Listed* Duct Temperature Sensor commercially available?
Click to expand...

Probably because there is nothing to list. All it is is a thermistor. Who want's it listed?

-Hal
 
I think the listing may be because the thermistor is packaged. You would have to look at the listing spec from UL to see what it is about.

Now, if you could get one of those duct sensor manufacturers to use one of those in their product I think you would satisfy your spec. :happyyes:

-Hal
 
Status
Not open for further replies.
Top