Nonincendive Circuits/Components in C1D2 Environment

Junki3JJC

Member
Location
Houston
Occupation
Design Engineer
Hello all,

Think I might have went down the rabbit hole a bit on this one, and looking for alternative thoughts - or at least confirmation that I'm on the right path.

It's been a while since I've looked at the likes of NEC 500, however looking at different aspects of an existing design, and what it would take to make it C1D2 compliant. One particular area I'm looking for clarification on is the applicability of the designation "nonincendive".
The reason I ask, there are various control components in this design (solenoids, proximity sensors etc.) that are already general purpose, however I'm looking into whether they could be considered nonincendive (I do need to dig further into the ANSI/ISA standards to check the criteria for this).

As an example, the solenoids themselves would classify as being allowed to be general purpose as they are not sliding or make/break (under 501.105 (B)(4), however they do use the DIN-style connectors on the housings, which I believe would then need to be compliant per 501.105 (B)(6) - so thinking I would need to further justify through "nonincendive" if I can, otherwise would need to explore further options e.g. IS barriers or switching out the solenoid itself to something else e.g. no connectors on it, C1D2 rated, or some other option.

With this, is it possible to make a justification / "self-assess" these components and therefore use them as-is, assuming they meet said criteria? Or do they need to be specially listed as such through UL and/or marked accordingly?

I'm coming from more of a background in ATEX where self-assessing is quite common, however getting a little bit down the rabbit hole in the requirements of the NEC and what is actually needed for this, so any kind of advice is welcome.

Thanks in advance all!
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Depending on which edition of the NEC is applicable, nonincendive is (vaguely) defined in Section 500.2 (2014 or earlier) or Article 100. In either case, the real information is in the latest edition of ANSI/ISA-12.12.01. There is no real analog in IEC, ATEX, or most importantly, NEC Article 505. By-the-way, Section 501.105 (B)(6) won't apply to the solenoids indicated in your link either since that Section only applies to cord-connected devices.

As a general rule, the NEC does not consider terminations, connections, or spices to be arc-making under "normal" conditions. - except maybe in Division 1 where they are in an enclosure with 2" or greater entries. In Division 2, they are pretty much ignored; i.e., Type "AEx e" connections are not required. (Note the "A" is required by Section 505.9(C)(2)(3) - ATEX just won't do in the NEC)

As a final note, nonincendive designs are a PITA for the end-user. They weren't always but ever since ISA took control over them, they have been.
 

Junki3JJC

Member
Location
Houston
Occupation
Design Engineer
Great, thanks! That makes a lot of sense. And apologies, I misread 501.105 (B)(6) thinking it continued with plugs/receptacles. Clearly this was not the case.

A further two questions, related in the same system (and then I think I'll have everything clarified/answered):

1. Regarding a general-purpose simple PLC (which I believe would be solid-state in respect to switches), per 501.115 (B)(1)(4), I believe this would be considered acceptable however a general question regarding the whole "surface temperature 80% of autoignition" - how is this typically executed? It's mentioned a lot throughout e.g. in the luminaires section, amongst others. Does it need to be tested and listed under UL (or whichever body), or is it possible to "self-assess" it for suitability and use as-is? I suppose since it's general purpose it would not need to be listed, however how would you prove the "surface temp" point? The other alternative is to dump it in an explosion-proof enclosure, however wanted to explore the ability to use as-is first.

2. Pressure transducers, e.g. https://www.grainger.com/ec/pdf/Johnson-Controls-P499-Transducers-Spec-Sheet.PDF, or the UL listing is https://iq.ulprospector.com/en/profile?e=85839 (I find it extremely interesting this is listed as a motor controller...), I see some listed as nonincendive (and I assume therefore would need a nonincendive source as well as segregation), and some listed as, well, a motor controller for whatever reason - even though I would have assumed it should have been listed under 501.105 (B)(3) as a "resistor". I think that going for the non-nonincendive (haha) ones would be appropriate/easier, and could be connected to a general purpose 24V supply, with the output connected to the PLC input without issue (whilst still following necessary wiring requirements). Does this sound correct?

P.s. after looking a bit further into the nonincendive circuit requirements, I think I agree with your statement of being a PITA...

Thank you!
 

rbalex

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Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
I can answer your questions, but it would help if I knew your perspective. Are you an OEM. a fabricator, a consultant, or an end-user? Your occupation could apply to any of them.
 

Junki3JJC

Member
Location
Houston
Occupation
Design Engineer
We would be the OEM using these components in modular assemblies/sub-assemblies. That said - and definitely don't want to burden you (or anyone else that might answer) with the explanation - but I'm curious what it would mean for the end user too.

Thanks!
 

rbalex

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Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
A bit of history. Code Making Panel 14 (CMP14) tried to get the definition of identified modified to clarify that it did not necessarily mean listed or labeled. It never did mean it but it's confusing in the Article 100 definition. The problem was many AHJs wanted products for Divison 2 to be specifically listed or labeled for Division 2 even when it wasn't necessary. CMP14 next tried to make a special Article 500 definition for identified. That didn't fly either. They finally settled on defining Suitability in Section 500.8(A). The definition was modeled on FedOSHA's definition of Acceptable in 29CFR1910, Subpart S, Section 399.

Section 500.8(A)(3) does permit a manufacturer's "self-evaluation" but it also requires the end-user to maintain a great deal of documentation. In addition, to be a FedOSHA acceptable application requires that the first two options be unavailable. Most StateOSHAs model their laws after FedOSHA or are under FedOSHA to begin with. With rare exception, most end-users want listed or labeled products although many will accept a manufacturer's documentation of suitability.
 
Location
Ohio
Occupation
Engineer
Hello all. What does PITA mean? Also by manufacturer do you mean the manufacturer of the machine the component is a sub assembly of, or the manufacturer of the component.

Sent from my SM-N960U using Tapatalk
 

rbalex

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Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
The "P" stands for pain. The rest of the acronym refers to where such pain may occur.

The OP would need to clarify the specifics concerning their activities.
 
Location
Ohio
Occupation
Engineer
Ah yikes, I stepped right into that one. PITA...., how did I miss the meaning of that...

I am very interested in the evaluation of non manufacturer identified components for CID2. You see a lot of devices that have the evaluation right on the manufacturer labeling. To me, this means that when they had the NRTL to evaluate it, they also evaluated it to the CID2 suitability. However, just because electronics does not have the CID2 labelling, doesn't mean it is not suitable. It could just mean the manufacturer declined to pay to have that testing done.

I've grappled with what is needed to evaluate certain products for a machine as a hole. From my reading of the NFPA 70 2017, a lot of times I can use the component if I can show through documentation or testing that it does not exceed the ignition temperature, plus a few other items of discretion that an Engineer should be expected to be able to think through, or test to...
 

GW1

New User
Location
CA
Depending on which edition of the NEC is applicable, nonincendive is (vaguely) defined in Section 500.2 (2014 or earlier) or Article 100. In either case, the real information is in the latest edition of ANSI/ISA-12.12.01. There is no real analog in IEC, ATEX, or most importantly, NEC Article 505. By-the-way, Section 501.105 (B)(6) won't apply to the solenoids indicated in your link either since that Section only applies to cord-connected devices.

As a general rule, the NEC does not consider terminations, connections, or spices to be arc-making under "normal" conditions. - except maybe in Division 1 where they are in an enclosure with 2" or greater entries. In Division 2, they are pretty much ignored; i.e., Type "AEx e" connections are not required. (Note the "A" is required by Section 505.9(C)(2)(3) - ATEX just won't do in the NEC)

As a final note, nonincendive designs are a PITA for the end-user. They weren't always but ever since ISA took control over them, they have been.

** Please advise me.
I have had some issues and confusing come out regarding with using the Cable Gland at the Class I Div 2 Location (NEC US).

Location : Class I Div 2 Hazard (Classified) Location in the U.S
Using Field Devices: Rosemount Transmitters (Pressure, Temperature),
Example: Rosemount 644 Transmitters with Class I Div 1, Div 2 Hazard (Classified) Enclosure .

** Rosemount's installation document note that " Installation per NEC , Conduit Seal Not Required for Compliance with NEC 501 - 5a (1) .

However, I even used the Classified Cable Glands (Classified) for entry of those Rosemount Transmitter for more precaution.
Using Cable Glands: PEPPERS Model: A2LBF with Certification NEC US : Class I, Zone 1, AEx e IIC Gb , with ANSI/UL 60079-7, UL 1203, UL 2225. and all kind of Recognized Certifications for other countries.

I understand that NEC US : Class I, Zone 1, AEx e IIC Gb , which is good for using in Class I Div 2 Hazard (Classified) Location in the U.S (NEC US).
Type of Protection = ISA 60079-7 = Increased Safety
Code = AEx e
Country = US
Class = Class I
Zone = Zone 1
Standard = ISA 60079-7
Basic Concept of Protection = No arcs, sparks or hot surfaces.

However, in the our project site (Class I Div 2 Hazard (Classified) Location in the U.S) , some people are notifying Red Flag that I am using this Cable Glands (PEPPERS Model: A2LBF) with Certification NEC US : Class I, Zone 1, AEx e for installation of field cable entry into the Rosemount Transmitters with Class I Div 1, Div 2 Hazard (Classified) Enclosure.

Rosemount's installation document note that " Installation per NEC , Conduit Seal Not Required for Compliance with NEC 501 - 5a (1) . Also reference with ANSI/ISA – 12.12.01-2000, “Nonincendive Electrical Equipment for Use in Class I and II, Division 2, and Class III, Divisions 1 and 2, Hazardous (Classified) Locations,”. Which mean that Nonincendive Field installation method is allowing to even use the General Liquid Tight Glands for installation cable entry into the Rosemount (Classified) Transmitters in Class 1 Div 2 (US). (So, I can use Nonincendive installation mathod using with General Liquid Glands complying with NEC Codes., but now I have use with Class I, Zone 1 AEx e Glands )

I am confusing and I am trying to prove that I am using this right selection of Cable Glands (Class I, Zone 1, AEx e) are good complying NEC Code for using in Class I Div 2 (Classified) Location in the U.S. , and no violations for any NEC code issues.

Please advise me.
Thank you.
George
Lake Forest, California 92630
Project Manager
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Ah yikes, I stepped right into that one. PITA...., how did I miss the meaning of that...

I am very interested in the evaluation of non manufacturer identified components for CID2. You see a lot of devices that have the evaluation right on the manufacturer labeling. To me, this means that when they had the NRTL to evaluate it, they also evaluated it to the CID2 suitability. However, just because electronics does not have the CID2 labelling, doesn't mean it is not suitable. It could just mean the manufacturer declined to pay to have that testing done.

I've grappled with what is needed to evaluate certain products for a machine as a hole. From my reading of the NFPA 70 2017, a lot of times I can use the component if I can show through documentation or testing that it does not exceed the ignition temperature, plus a few other items of discretion that an Engineer should be expected to be able to think through, or test to...
There are many Code concepts to consider. Begin by reading Section 500.8 carefully; especially Subsections 500.8(B) and (C) - but read and absorb the whole Section.

Some basic rules are often modified, not by Exceptions but direct Text. For example, the general marking rule in Section 500.8(C) draws attention to the idea that it may be modified in Section 500.8(C)(6). For Class I, Division 2 this is especially important in Subsection 500.8(C)(6)(a) where it notes most general purpose equipment that is acceptable in Division 2 isn't required to be marked for Division 2.
 

rbalex

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Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
...

** Rosemount's installation document note that " Installation per NEC , Conduit Seal Not Required for Compliance with NEC 501 - 5a (1) .
...
I have no idea what "NEC 501 - 5a (1)" refers to - so I'm confused too. The odds are what you are doing should be acceptable, but I don't understand the full scope of the installation.
 
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