Intrinscally safe solenoids and non IS cables


Thread Starter



First timer here. I have a question about intrinsically safe application. So, is it OK to use non IS rated LED illuminated solenoid DIN cable to connect IS rated solenoid that is fed from a IS barrier?
Or, in other words, is it OK to use simple device (one that cannot store energy) to connect to nonsimple device (one that can store energy) and still stay intrinsically safe?

Thanks a lot

Bruce Durdle

You can connect only IS-rated or simple devices into an IS-protected circuit. So, provided your IS-rated solenoid is compatible with the barrier you are using, that should be OK. I'm not sure what is meant by "non IS rated LED illuminated solenoid DIN cable" but if it is a cable with a pre-installed LED to indicate the status of the circuit it COULD be OK. Safest way - ask the supplier of the barrier if the circuit you propose to use is safe with the equipment supplied and, if so, add this information to the dossier for your site.
As Bruce indicates, it may be ok. However, the IS principle depends on both the barrier limiting that amount of energy that can be passed into the Hazardous Area AND that the stored energy in the circuit is below the level that generate a spark. IS circuit design requires that you perform calculations to ensure that any inductance or capacitance in the circuit (including connecting cable) is below the acceptable limit specified for the barriers used.

Another consideration is that it is an industry standard that cabling for IS circuits has an outer light blue sheath.