Area Classification

You can likely use either or both in theis case, it is really going to depend on what you are wanting to do in the hazardous area and what equipment, sensors, remote IO, etc you are planning on using. Additionally also on how much the equipment costs when comparing Ex i versions to Ex d versions.

Start by looking at what equipment you want to use, if it is all intrinsically safe then that is probably your best bet. If a lot of it is standard equipment that you want to try and use by putting it in Ex d enclosures and having it certified, then a cost/benefit analysis is in order to see if this is going to be a better and/or cheaper alternative than using certified hazardous area-rated equipment.

You can't mix wiring methods. Exd and IS are two seperate types of wiring methods. In order to use Exia your field device must be approved IS (Intrinsically Safe). Your field device as well as the area classification will determine how you wire this up. This first question to ask is how your device is approved. That will get you pointed in the right direction. Good luck!

The need to ask such a question suggests that attendance at a suitable training course is overdue.

• Ever seen an Ex ia electric motor?
• Ever wondered why not?