Explosion Proof Enclosure

Dear All,
I have one query regarding the explosion proofing of Junction box. I have a pressure switch in field commected to JB & going to control room. I am connecting pressure switch to DCS through a barrier. Can i stil use EEx'd'
junction box even after connection the switch through barrier. Once i connect the switch through barrier is it that whatever may be thr junction box like Exi, EEXe or EEx'd'.

Be aware that the pressure must meet the requirements for "simple apparatus" if it is to be used on an IS circuit and is not itself certified as IS. This means that there are restrictions on any additional circuits used - usually not a problem. There are again no limits on how you connect the IS circuit and it is permissible to use an Ex d terminal box. However, there are a couple of things to check: - If there are other non-IS circuits in the Ex d junction box, you need to be very careful to maintain the required separation between Ex i and non-Ex i circuits - usually at least 50 mm unless there is earthed metal between. - You need to make it clear by labelling or in some other permanent way that the JB contains Ex i circuits.

Bruce

How will the IS signals enter/leave the Ex'd' junction box? It will be far easier if they are in separate cables and you don't try to mix them with non IS signals in the same multicore.

Steve

www.mtl-inst.com

Definitely separate cables...