Hazardous Locations

I am supposed to be working on a quote for a project going into a hazardous location. Is it just as simple as purchasing componentents rated for the proper class/div/group? What special wiring methods are required? When does one use galvanic isolators?

Any suggesting reading that will get me up to speed?

Thx!

another thread was recently posted about that

You first need to know which kind of aread classification you need :

Class 1 (Gaz) Class 2 (Dust)
Div 1 explosive stuff always present Div 2 explosive may be present
Group ....(Size of explosive molecules)
Temperature code to ignite

Than you'll probably need a panel approval if it is for a new installation...You'll get it by having a classified panel shop to do the work or get your specific design approved.

To get this approval, you need to have everything to meet the class needed or get individual parts tested as non explosive under specific condition etc...

depending of your site requirement, their is some different solution availaible from having everything at low voltage non sparking or enclose it in a safe and solid 1 inch thick panel or have so clean purging air comming in to keep explosive away...ETC

Give us some more clues so we can help guide you. We can't read your mind.

It's not just as simple as ordering the right equipment...

Sorry, I posted my questions too soon... half an hour after my post I received a very lengthy email from the engineering company detailing the class/div/groups as well as a bunch of other info that I need to digest!

you're in usa, do you need a UL xproof certification ?

I read the info from the engineering company.

We are furnishing 2 pieces of equipment which I will call "A" and "B". Both located in the same room. Both pieces of equipment have large internal "cavities". Equipment A feeds product into Equipment B.

Equipment A has a rating of Class II, Div 1, Group G for electrical devices inside the internal "cavity". For external electrical devices, the rating is Class II, Div 2, Group G. They define "device" as instrumention, motor disconnects, HOA switches, electrical termination boxes on the equipment.

Equipment B has a rating of "General Purpose/Ordinary" for both internal and external electrical devices.

All motors are Class II, Div 2, Group G.

They want all enclosures to be Nema 4 or 4x. Evidently they periodically plan to wash things down to eliminate build-up of dust.

They did not furnish any class/div/group info for the control cabinets themselves. These control cabinets seem to be located directly next to the equipment they control.

Since the engineer company has multiple class/div/groups in the same room, I have asked for clarification on how they are classifing the actual control panels housing the PLC(s).

I just completed design on a project for Class 2 Div1&2 enviroments. Section 500 of the NEC covers hazardous location. The NFPA website also has a great deal of information on the subject. As stated by Jeff23spl the requirements depend on the Class, Division and Group ratings.