Intrinsically Safe Barrier Installation

[CKMEYER]

This is likely a simple question, but it is one I have received two different answers to - from multiple people/vendors/PE's etc. So I am coming to a web forum to try and get a consensus...hmm..:grin:

Anyways, installation of an intrinsically safe barrier for an intrinsically safe circuit in a class 1 div 2 area - my thoughts, along with others, is that the barrier itself needs to be installed in a non-hazardous location (or rated enclosure) and the I/S side of the circuit will continue on into the C1 D2 area. However, I hear from the other side of the coin that since the barrier is stamped "Class 1, Division 2, C&D", the whole barrier can be placed in the hazardous area (since it is basically a sand filled fuse, zener diode, and resistor attached to a terminal block - non-arcing, sparking, or heat producing). To me, a zener barrier is not exactly a simple device (b/c of the diode), and as such, cannot be in the class 1 div 2 area - but I can see the argument from both sides.

Any opinions?

 

[KentAT]

If they are certified for Cl I/Div 2/ C&D, they can be placed in Cl I/Div 2/C&D.

Not all are certified as such.

 

[Smart $]

...

Any opinions?

Mine is an intrinsically safe barrier is intended to go on the non-hazardous side of a classified boundary. The purpose of a barrier is to prevent any explosion-igniting, arc-generating voltage or current from entering a classified area.

However, with that said, wiring methods within classified areas are not required to be intrinsically safe... so a barrier could be placed within a classified area (where rated for such) to make a transition from a non-intrinsically safe wiring method to one which is intrinsically safe.

 

[james_mcquade]

I have a question for you.
If your device is rated for the classified area, what about the wiring to the non-classified wiring?

We always place the barriers in the non classified area and run the wiring to the hazardous area using rigid conduit and conduit seals.

regards,
james

 

[Smart $]

I have a question for you.
If your device is rated for the classified area, what about the wiring to the non-classified wiring?

Has to be done using non-intrinsically-safe, hazardous-location wiring methods.

We always place the barriers in the non classified area and run the wiring to the hazardous area using rigid conduit and conduit seals.

Hmmm... running rigid and installing conduit seals seems to negate the main reason for using intrinsically safe circuits... but doing so is certainly not detrimental from a safety viewpoint.

 

[bobgorno]

Access the control drawing for the barrier. Either the drawing or the notes will tell you if the barrier is approved for mounting in a Div. 2 location when installed in a suitable enclosure.

Note - suitable enclosure in a D2 area doens not mean XP.