Purged panel & pushbuttons

A bit off topic, but I'm sure this esteemed thread will have some answers. I'm having a debate with our engimneering group on what push buttons to use on a purged panel in a class 1 div 2 area. The purge I think is a Z purge (alarm only). I contend a stanadard pushbutton is OK, engineering says I have to use explosion proof. What say you?

From a purely technical viewpoint, you are both wrong. If engineering says "explosion proof" is required, no, the most severe case would be pushbuttons rated for Class 1 Division 2, not "explosion-proof" (whatever that means). Note that many pushbuttons that you may call "standard" (whatever that means) such as the Square D Class 9001 Type K, SK, or KX are qualified to be used in a Class 1 Division 2 area.

If I will be working in the area, then I would use pushbuttons that have a Class 1 Division 2 rating. One the other hand, if the engineering guys are going to be the only ones working out there around the purged panel, then I would just use any old switch off the shelf.

The definition of a Type Z purge makes a Class 1 Div. 2 area non-hazardous. So if it's realy a type Z purge, so should be able to use standard pushbuttons in the panel.

With a purged panel, I would recommend NEMA 4 rated buttons to maintain the purged integrity.

I can buy a standard pushbutton at Walmart for a doorbell button, but I don't think that would work too well. "Standard" doesn't mean anything. Standard for what, whom, and where? The best bet is to specify a brand and type, then you know something about the pushbuttons.

If you work in one plant that uses only one type of button, then maybe you can call it a plant standard. But that standard button might be rejected by another plant next door - it could use a completely different "standard" pushbutton.

I suppose this comes from working for a contractor in too many different plants with too many different standards that each one thinks is the cat's meow.

if the engineering guys are going to be the only ones working out there around the purged panel, then I would just use any old switch off the shelf

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Lancie, did not you were such a big fan of engineers!!

Bruce, I were one, after being a farm hand, a busboy, a sewing machine mechanic, electrician, and a few other things for short periods (logger, heavy equipment operator, technical writer), so should be allowed to poke fun at that group "as a hole".