I am presently using a hermetically sealed enclosure for a single pushbutton unit in a Class I Div 2 area. The AB 3-position momentary pushbutton has 1 N.O. and 1 N.C. contacts rated for Class I Div 2.

I need a contact block of 1 N.C. and 1 N.C.L.B. for the pushbutton and AB does not offer such a contact block rated for Class I Div 2. I can achieve the same results of the needed type of contacts with the existing contact block and some relays in the non-rated control cabinet, however I would like to save some money and space.

So I have two questions:

First question: Do I need a rated contact block since the contact block is in a hermetically sealed enclosure?

Second question: For other applications, different from the above described issue, if I have a Class I Div 2 rated pushbutton unit, is it necessary to install it in a hermetically sealed enclosure? Or can a general purpose enclosure be used with the appropriate type of seal-offs at 18 in. from enclosure and +/- 10 ft from boundary?