CID1 approved 19" Rack Enclosure

[Srknet]

Hello,
is there an off-the-shelf CID1 approved 19" rack enclosure available with purge and pressurized protection? I have a product in a 19" rack enclosure and would like to use it in a Hazardous area. any suggestion would be appreciated.
Regards,

 

[petersonra]

If you want to purge and pressurize something it needs to be in a gasketed enclosure. I don't think you're going to find a 19-in rack that is gasketed.

My inclination would be to either try to find a different place to locate the rack enclosure or just to put it inside another enclosure.

 

[Srknet]

Hello,
thanks for the reply,
Agree that you can't have a 19" rack as is but is there any closed CID1 purged enclosure available that has a 19" mounting structure inside ready to use?
regards,

 

[petersonra]

Hello,
thanks for the reply,
Agree that you can't have a 19" rack as is but is there any closed CID1 purged enclosure available that has a 19" mounting structure inside ready to use?
regards,

There might be. I've never come across one. Normally I would just buy a listed purging system and attach it to a gasketed enclosure. I have not had to do so for quite some time now so maybe there are more options available but I don't know that there's any rack enclosures available that come with the purging system already attached.

There's no reason why you can't buy the frame yourself and just install it inside a normal gasketed enclosure. Bare frames are relatively easy to come by.

 

[Srknet]

Hello,

thanks for your quick response here.
Time constraint and design efforts only concern with buying a certified purged enclosure and mounting frame inside but that would be the option eventually to go.

one more question, Do I need all components integrated/mounted inside the UL certified purged enclosure to be UL rated/recognized or I can use non-rated components in order to have UL certification for complete assembly? because when I spoke with UL engineers they said all components have to be listed/recognized or UL evaluated? the problem is the UL evaluation, we would have to disclose a lot of design-related documents which our partners always reluctant to share. is there a way we can get away with this requirement? do the SELV component exempt from this requirement?

 

[petersonra]

Hello,

thanks for your quick response here.
Time constraint and design efforts only concern with buying a certified purged enclosure and mounting frame inside but that would be the option eventually to go.

one more question, Do I need all components integrated/mounted inside the UL certified purged enclosure to be UL rated/recognized or I can use non-rated components in order to have UL certification for complete assembly? because when I spoke with UL engineers they said all components have to be listed/recognized or UL evaluated? the problem is the UL evaluation, we would have to disclose a lot of design-related documents which our partners always reluctant to share. is there a way we can get away with this requirement? do the SELV component exempt from this requirement?

My suggestion is to just have the cabinet built by a UL 508a industrial control panel manufacturer. They can list it for you. Buy a listed purge system.

It is hard to know what you can and can't do as far as what you can put inside the enclosure and still get a UL 508A listing. There are some provisions for using non-ul-listed or recognized components but they tend to be fairly restrictive in what you can do. It is not possible to tell you what you could or could not do without knowing a whole lot more about what it is you're trying to accomplish.

Your best bet is to see if there's some way you can move it to an area that is not class one div one. Depending on what's inside the enclosure you may be able to put it in a class one div two area which might be a few feet away, or a non-classified area which might be 15 ft away.

 

[cpickett]

Your best bet is to see if there's some way you can move it to an area that is not class one div one. Depending on what's inside the enclosure you may be able to put it in a class one div two area which might be a few feet away, or a non-classified area which might be 15 ft away.

We have done a fair number of purge systems and I would try to move equipment out of the classified area every time. Just keep what is absolutely necessary (switches, indicators, field devices, etc) inside the classified area. Purge systems are an easy solution but maintenance and operation is a pain with the purge. As you increase the number of penetrations in your cabinet sealing becomes a challenge and the air consumption increases dramatically.

That being said, the mechanical parts inside your enclosure (the 19" rack) don't have to be UL listed in order for the assembled enclosure to get a UL listing for Class I Div 1. Darn near everything electrical does though, so that may put the brakes on this anyways. Panel shops can get recognized or unlisted components added to their procedure so they can be used but that is time and $ (as with everything UL).

 

[petersonra]

That being said, the mechanical parts inside your enclosure (the 19" rack) don't have to be UL listed in order for the assembled enclosure to get a UL listing for Class I Div 1. Darn near everything electrical does though, so that may put the brakes on this anyways. Panel shops can get recognized or unlisted components added to their procedure so they can be used but that is time and $ (as with everything UL).

UL has some allowances for non UL parts.

44.2.1 Components and internal wiring located entirely within a Class 2 circuit are not required to be
investigated.

APPENDIX B – (informative) – USE OF COMPONENTS NOT UL LISTED OR RECOGNIZED IN
INDUSTRIAL CONTROL PANELS

A purged panel would not be listed for C1D1. It would be listed as a normal UL508a control panel. The pressurization/purging system would be listed for C1D1, or C1D2 as appropriate. The purging/pressurization system effectively changes the space inside the UL508a control panel from hazardous to non-hazardous.

You can also get hazardous area listings for control panels via UL1203 (XP) or UL698a (IS).

 

[cpickett]

Lots of details to get right for a true UL listing!

 

[Srknet]

Thank you @cpickett and @petersonra for detailed information and guidance.

We recently certified one product with UL for CID1 using Ex d enclosure so I got an experience and a pain to go through the UL procedure for using/making listed or recognized components. Do you think the panel shop accepts the non-rated component if operated with an NEC Class 2 power supply i.e. PCB with 5V or 12V?

One more question, if we integrate all components into the approved purge/pressurized enclosure and put the device in the hazardous area without UL certification, and do only the field evaluation by UL/TUV or any NRTL certified body then would it be allowed as per NEC requirements?

 

[cpickett]

One more question, if we integrate all components into the approved purge/pressurized enclosure and put the device in the hazardous area without UL certification, and do only the field evaluation by UL/TUV or any NRTL certified body then would it be allowed as per NEC requirements?

I think the 'correct' answer is no. However I will say that most of our work is industrial, and most of our customers have insurance companies that are the AHJ, not a local inspector. Even though we have a UL panel shop, maybe 1 in 100 panels actually leave with a UL sticker. We build all panels as if we are building a UL panel, but most customers don't want to pay for the UL rating, and if their insurance required it you bet they would.

Now if you are selling a product the UL listing probably is more important as a 'selling point'. Rather than our panels which are custom built for each customer.

 

[petersonra]

Thank you @cpickett and @petersonra for detailed information and guidance.

We recently certified one product with UL for CID1 using Ex d enclosure so I got an experience and a pain to go through the UL procedure for using/making listed or recognized components. Do you think the panel shop accepts the non-rated component if operated with an NEC Class 2 power supply i.e. PCB with 5V or 12V?

One more question, if we integrate all components into the approved purge/pressurized enclosure and put the device in the hazardous area without UL certification, and do only the field evaluation by UL/TUV or any NRTL certified body then would it be allowed as per NEC requirements?

NEC does not care if the control panel is listed or not. Some locales though have rules that would require it.

The field evaluation is a way of listing the panel after it is installed. A field evaluation is pricey though.

If you get it built by a UL508a panel shop you would get whatever benefits there are of listing it without paying for the field evaluation. Chances are, the panel built by the panel builder will cost you about the same as if you built it yourself, or maybe even less.