Enclosure requirements in Class I, Division 2 and Class I, Zone 2

[CaptainATEX]

Hello,

The Intro:
Forum newbie here. I have a decent amount of experience in ATEX / IECEx requirements, but am mostly unfamiliar with requirements for the USA.

I am part of a design team creating products for the process industry. I personally handle all ATEX / IECEx approvals aspects for the team... but now I'm starting to branch into the N. American approvals schemes.

The background:
We have acquired a cCSAus approval on a device that measures a few process variables. The certificate of conformance states...

Class I, Division 2, Groups A, B, C & D
AEx nA nC IIC T4 Gc

Device is rated 32V and 29mA; Temp. Code T4; Ambient temperature range: -40?C to + 85?C;

Condition of Certification: This device is an OPEN type equipment that must be used within a suitable end- use system enclosure. The suitability of the enclosure is subject to investigation by the Local Authority Having Jurisdiction at the time of installation.

After reviewing the NEC (NFPA 70, 2011) section 501.105, I am unsure what type of enclosure the end user is required to provide. Obviously, our marketing and sales folks need to have a good understanding of how this device can be utilized in the market. Additionally, there is a business opportunity to provide an additional service to the customer by placing this into an enclosure for them.

The questions:
1.) What enclosure requirements exist for the installation of this product in both Class I, Division 2 and Class I, Zone 2 applications?
2.) Would further certification assessment need to be performed for the combination of this device and its enclosure?
3.) Does the answer change any if this is installed in the same enclosure with a few other devices with similar ratings?

I hope this question isn't too long... any input or advice is welcome.

Thanks!!
Aaron

 

[rbalex]

Welcome to the forums.

1. Technically, any enclosure listed in Table 110.28 would work for your product in NEC Division 2 or Zone 2; just review the Table for other appropriate application conditions.

2. Not necessarily.

3. Possibly, but not if they have identical ratings.

 

[CaptainATEX]

Thank you rbalex! That is good news for us.

How would one go about interpreting the NEC to come to this conclusion - what section would you point me to for this?

For Class I, Div2, I thought I would find my answer at 501.105 (B)... but I didn't seem to find anything there that would help.

Thanks again for the help.
Aaron

 

[CaptainATEX]

Welcome to the forums.

Thanks!

1. Technically, any enclosure listed in Table 110.28 would work for your product in NEC Division 2 or Zone 2; just review the Table for other appropriate application conditions.

This is great news for us... thank you.

How would one come to this conclusion from the NEC - what section would I refer to to see this?

I initially reviewed Table 110.28, but saw the statement:

Table 110.28 shall be used for selecting these enclosures for use in specific locations other than hazardous (classified) locations.

I then was reviewing section 501.105 and could not come to a final conclusion on how to interpret the enclosure requirements for this product. Am I missing something (I think the answer is yes....)?

Thanks again!!
Aaron

 

[CaptainATEX]

Oh, and one more question...

Are there any requirements to mark the exterior of the enclosure of these products? If yes, where would I find the details of the required marking?

Again, thanks for the help,
Aaron

 

[rbalex]

For Class I, the missing "hazardous location" Type from the Table is 7 (explosionproof). Section 501.10(B)(4) notes explosionproof enclosures are not required in Division 2 unless specifically required by other Sections. In your case, 501.105 (B)(1) doesn't appear to apply.

Since this is a CSA certification, you are being told that your product is incomplete on its own. In UL terms it would be a "recognized component". Certifying a whole assembly is recommended but not necessarily required if the AHJ knows what they are looking at.

Exterior markings are up to the certifying agency's practice.