Hi guys,

I would like to find out more on guidelines to design an explosion proof electrical control panel. In hazardous area, i understand that this eletrical control panel will be confined to an area which is designated for all the control system.
My application now involves some swithing near to say, paint storage area which is classified under hazardous area. This particular electrical panel cant be located at a particular area as it is mounted on a mobile unit.
QUestion is, how to make this electical panel to be explosion proof (intrinsically safe)? In market there are Ex rated solenoid valve, but what about relays, switches, etc.
Thanks for your help

 

Hi there,
My company is just in the middle of doing an automation system in a class 1, div1 location. After doing a lot of investigation for this I found that using a type x purge unit for on the control panel is probably the most economical way to go. If you want more information you can email me.
[email protected]

 

If the components you use inside panel will produce sparks, then you must use a purged air system or Ex 'D type aluminum alloy boxes.

Choose a size for your panel.

When calculating the size, remember that these panels are very expensive and PVC trunkings and similar hard ware are to be avoided as there is no space luxury inside. Design with point to point wiring with minimum loose wires.
If you can buy a Ex 'D' aluminum alloy for that size go for it. Tell your explosion proof box supplier to provide as many switch and push button threads you need and more cable entry holes than you need. Except the cable entry point and switches and push buttons you can use general type components inside.

If you panel is bigger than avilable boxes, go for a air or nitrogen purged system panel.

The certification is only for the purging system and you can use normal components in the panel and water / air tight components for the switches and push buttons. Visit some plants to have more idea or consult a supplier on choices.

regards,
Sekar

 

To determine your requirements, you need to specify where you are. Hazardous Area classifications and explosion proofing requirements are different in North America and Europe.

 

Eugene,

You have some options, like purged and pressurized, and explosionproof.

Using explosionproof enclosures, you can install industrial components inside; a purged and pressurized one will require the source of compressed air at site. It is important to know first, if the area is Division 1 or 2.