Non-Incendive Circuits

[fifty60]

For Class I Div II locations, I know that thermocouples can be can be considered non-incendive circuits. Does this apply for as well for Class I Div I locations as well? Non-incendive circuit is not an acceptable protection technique for Class I Div I, so for thermocouples, would have to run them through Intrinsically Save barriers or use some other approved technique? Or, are thermocouples OK by themselves in a Class I Div I?

For example, if I used Intrinsic Safety as my protection technique. Thermocouples would be considered simple apparatus and not need to be intrinsically safe. Intrinsically safe is an acceptable method for Class I Div I, so would I be able to say that the thermocouples are safe As-Is using intrinsic safety, but not actually running them through a barrier because they are simple apparatus?

 

[fifty60]

I understand better now. A simple apparatus still needs to be part of an IS circuit, the only difference is that it does not need to be approved as IS devices on their own. So you can simply connect a simple apparatus to an intrinsically safe barrier without the entire simple apparatus being approved as IS

 

[fifty60]

Can intrinsically safe barriers only be used on simple apparatus? Otherwise, the apparatus itself must also be intrinsically safe? To clarify, I can take a Thermocouple and put it on a barrier and that is OK, but, I can't take a...non-passive component that consumes 110VAC and 20W and expect to put a barrier on it and be able to call it intrinsically safe?

If the component itself is not a simple apparatus, then the component itself has to be approved as intrinsically safe?