23 May 11 13:37
We want to buy a European intrinsically safe ultrasonic meter for our USA manufacturing site. The classification of our site is Class I, Div 1, Group C, and also Class II, Div 1, Group G. The device has the following listing:
Ex ia IIc T3/T2 Ga
Examining the listing into its components I read:
EX ia – means intrinsically safe for Class I, Zone 0 areas (equivalent to our Div 1)
IIC- Atmospheres of acetylene, hydrogen (NEC FPN Group IIC is equivalent to Classs I, Group A)
T3/T2 Temperature code same as NEC 300/200C (don't know why there are two temps)
Ga – describes the type of protection 'very high' in this case.
However, NEC 504.4 "All intrinsically safe apparatus and associated apparatus shall be listed. Exception: Simple apparatus"
This device does NOT meet 'simple apparatus as defined in 504.2 (at least to that I can see based upon its opera ting voltage of 20.4 volts
Listed, usually means by a NRTL (nationally recognized testing laboratory) and it would typically include the Class, Division, and Group on the nameplate.
It was my understanding that the European listing was one self certified by the company.
Do you believe that this IEC listing is sufficient for the USA classes mentioned?
Do you thing NEC wants to see a label other than saying 'Intrisically Safe' but also wants Class, Div, and Group on the label.
Appreciate any advise.