Class-2 Div-II Enclosure

Greetings,

We have a process with an touch screen and several control switches installed in a pressurized enclosure. We've had issues where the power status of the machine couldn't be determined because the screen went blank. I would like to add hardwired pilot lights, but because of class-1 div-II, they would have to be of the A-B 800H variety (protective cage around the lens). These are hard to clean and therefore undesirable.

I've considered putting standard LED pilot lights behind a small section of safety glass that would be sealed against a cutout in the front of the enclosure. Are glass inserts permitted in this environment?

Intrinsic barriers are a possibility as well, but I would have to add relays for the AC lamps.

Any thoughts?

Grover

if you use relays use hermetically sealed relays

Thanks for the reply, nswu1.

Perhaps I'm missing a fundamental point (very likely). If the panel is pressurized and monitored for loss of pressure, can't the internal components of the enclosure be standard NEMA 4/13 components? The only thing I am proposing is to place some 16MM pilot lamps behind a piece of safety glass. The glass would be sandwiched between the enclosure (the metal surrounding the cutout) and a piece of stainless steel attached to studs inside the enclosure.

Are hermetically sealed relays necessary for this application? I brought relays up as an alternative to the glass idea. If I use intrinsic barriers, I would need to convert the AC lamp signals to 24VDC through a relay. The relays would likely go into the main control enclosure outside the process area, upstreamm from the instrinsic barriers.

One point of clarification. The room is class-2 div-II and not class-1 as indicated in my original post.