IS certified instruments in safe area

[19Marc85]

Hello,

I am new at Mike Holt's forum and first of all friendly greetings to all forum members. My name is Marc and I am working as an instrumentation engineer in europe. We are currently working on a project for the USA, where the electrical installation is covered by NEC 2011.

My question maybe sounds a little bit strange but I am also facing a strange situation.

In our project, we got specified to purchase IS certified instruments (IS Class I, Div I, Group A-d, T4) although our machinery train is completely located in safe area. Now we are discussing about how to apply instrument installation.

According to NEC, is it mandatory to intend intrinsically safe loops for the installation of IS certified instruments even if I am located in safe area? Or is there anything that prohibits to install them like any other uncertified instrument the same way without consideration of any hazardous protection technique?

Thanks in advance for your support!

 

[rbalex]

Welcome to these forums.

There in neither a requirement nor prohibition for using IS in unclassified locations.

It is possible that some of the wiring may run through a classified location even if your equipment is not in it and IS may be useful. It still isn't likely to be required, but customer specifications are customer specifications.

If IS is used, you or the instrument manufacturer will be required to create a control drawing per Article 504 for the use of your product in IS applications.

It is also likely you will be required to provide a third-party certification. ATEX and "CE" are not recognized in the US.

A few other basics for your information; per the US National Electrical Code (NEC), for "Divisions":

• "Classes" are designated with Roman numerals: "I", "II" and/or"III"
• "Divisions" are designated with Arabic numerals :"1" and/or "2"
• "Groups" are always capitalized: "A", "B", "C" and/or "D"
• The "T" reference is always capitalized

You did pretty well though, many experienced "natives" still have problems using the correct designations.

 

[GoldDigger]

If IS rated equipment is called for in the spec but is not required by code it seems at least a little ambiguous whether full IS compliance including control drawing is required.

Tapatalk!

 

[rbalex]

If IS rated equipment is called for in the spec but is not required by code it seems at least a little ambiguous whether full IS compliance including control drawing is required
Tapatalk!

Maybe I should have said, "If IS systems are required ..." It's similar to the problem of over-classifying a location; once a requirement has been established you have to go all the way whether the original requirement was necessary or not.

EDIT ADD: Requiring IS equipment is not the same as requiring IS systems.