Does anyone know the rules on devicenet installations in Cl. 1 Div. 2 areas??? We have plug connectors to various devices (which are rated Cl. 1, Div. 2) and I am told I'll need "lock fast" jackets over connectors (to avoid any chance of them falling out) but I can find no written evidence of this.  These plugs are made such that they disconnect conductors before they are exposed.

While I'm familiar with classified locations I wasn’t familiar enough with DeviceNet to respond to your question immediately.  I did a bit of research at www.odva.org to get a better handle on it. What I found would lead me to believe it would not be an acceptable application as you have described it so far. But there is good reason to believe an acceptable installation can be made.

I’m using the 2002 edition of the NEC as the basis; conceptually, 2005 applications would be the same. The applicable section would be 501.14, but it refers back to the general Sections for specific applications.

Acceptable wiring methods for Class I, Division 2 are listed in Section 501.4(B).  One of the methods is “Nonincendive field wiring” described in 501.4(B)(3). Read it carefully as there is a fair amount of documentation necessary to apply it. I found several acceptable power supplies listed on the ODVA site under the DeviceNet Catalog (on the left) then Products by Category/Physical Layer Components - Power Supplies.

The connectors you described initially are not acceptable alone. It would still be considered a “make-and-break” contact and need to be installed either under 501.3(B)(1) or possibly, 501.3(B)(6) unless it is covered under nonincendive field wiring.