Class 1, Div 2 - Remote I/O Panel

[dbuschor]

I'm working on field wiring schematics for a Remote I/O panel to be installed in a Class 1, Div 2, Group D location. The panel is type 4x with an AB 1494V non-fusible disconnect.

The panel contains an AB 1492-CB1 10 amp circuit breaker that feeds a sola 24DC power supply. All other components (1794 Flex I/0) are UL listed for Class 1 Div 2 ABCD location.

Question: Does the Disconnect and CB meet code for Class 1 Div 2 group D installations?

Thanks

 

[don_resqcapt19]

Re: Class 1, Div 2 - Remote I/O Panel

In my opinion, neither the switch nor the circuit breakers are permitted by 501.6(B)(1).
Don

[ September 24, 2004, 10:48 AM: Message edited by: don_resqcapt19 ]

 

[rbalex]

Re: Class 1, Div 2 - Remote I/O Panel

I did a brief review of the AB online guide and didn't find anything to indicate any products in the Bulletin 1492 or 1494 series were suitable for direct application in Division 2.

With the installation in a 4X box, I suspect the intended protection method is "purged / pressurized," per NFPA 496.

With regard to "All other components...," its fairly easy to get non-arcing, sparking or heat-producing (ASH) products "listed" for Division 2 and, even if it isn't their most common application, manufactures have those products so listed to avoid having to carry multiple product lines. (My PDA is listed for "Class I, Div 2, Group A,B,C,D")

 

[dbuschor]

Re: Class 1, Div 2 - Remote I/O Panel

What about 501.6 (B)(2)? Can the disconnect be classified as a isolating switch that is not intended to interrupt current in the normal performance of the function?

The panel is being supplied by (what I thought was a reputable) panel builder who is also supplying a MCC panel (with is purged/pressurized) for the same project. I don't think they intended to purge/pressurized the Remote I/O panel, which led me to wonder how they were getting past the code.

I wasn't sure if there was an exception since these devices are not normally intended to interrupt current and by adding a label next to each device instructing not to open unless environment is known to be nonhazardous.

 

[rbalex]

Re: Class 1, Div 2 - Remote I/O Panel

Is this a transformer or capacitor bank?

 

[dbuschor]

Re: Class 1, Div 2 - Remote I/O Panel

The disconnect switches a single 120V AC control circuit which is protected by the 10 Amp CB. The only thing the control circuit currently feeds is a 24V DC power supply (which is protected with an addition 10 Amp fuse). All the remaining components are 24V DC remote I/O (AB 1794 Flex I/O) devices.

 

[rbalex]

Re: Class 1, Div 2 - Remote I/O Panel

I apologize for the cavalier nature of my previous reply.

In all candor, I've only met a few HazLoc knowledgeable folks more permissive than I am with regard to classified location installations - and I don't think any of them would concur with applying the switch or CB as you have described the installation so far.

"Purged/pressurized" is the minimum protection method I can see applying here.

 

[petersonra]

Re: Class 1, Div 2 - Remote I/O Panel

Originally posted by rbalex:
I apologize for the cavalier nature of my previous reply.

In all candor, I've only met a few HazLoc knowledgeable folks more permissive than I am with regard to classified location installations - and I don't think any of them would concur with applying the switch or CB as you have described the installation so far.

"Purged/pressurized" is the minimum protection method I can see applying here.

It may be that they intend to purge both the MCC and the RIO panel. Its possible to pressurize the RIO box and exhasut it into the MCC (or vice versa) such that the same pressure source and indicating instruments take care of both the MCC and RIO panel.

 

[dbuschor]

Re: Class 1, Div 2 - Remote I/O Panel

Thanks - I really appreciate your time/responses... I'm a newbie when is comes to Class I installations, but I always respect the code (although sometiimes I have a hard time understanding it).