Instrumentation listings-UL or NRTL

[thinfool]

We have been working with an integrator installing ultrasonic heads in wastwater manholes to measure the amount of wastewater being returned to the city for treatment.

The heads are low voltage and intrinsically safe and are served by a factory installed jacketed cable from the manhole to the recording instrument in the nearest building.

Our inspector wanted to see a sticker or other indication that a NRTL had certified these flow meters.

My question: Where in the NEC is this required?

The factory people were incredulous...apparently they had not had anything like this happen before.

 

[Pierre C Belarge]

The inspector may have been referencing
504.4 Equipment.
All intrinsically safe apparatus and associated apparatus shall be listed.

 

[megloff11x]

UL isn't the only game in town. OSHA recognizes them and CSA (Canada), TUV (GErmany), and a number of other agencies as competent to inspect and stamp as good any manufactured widget with wires. They all have offices in the USA.

NRTL is nationally recognized (by OSHA) test lab.

You may notice that your computer has more little logos than a NASCAR. These are all country-specific NRTL agencies.

Matt