Class 1 Div 2, Flexible Conduit, and Low Voltage.

[Dan LV]

Thank you in advance for any help provided. The situation I am dealing with involves a class 1 div 2 building in which we have quite a few devices that need to utilize liquidtight or something similiar. The manufacturer, upon our request, said that liquidtight by itself would be adequate to run from the rigid pipe to the device (2-3 feet), taking into consideration these devices are at least class 1 div 2 rated. Since then we have been told otherwise. When I look over the 2014 edition of the NEC I feel as though we should be able to use liquidtight as is. At worst I get the impression that a bonding jumper may be required. Some educated input would be great at this point. My "assumptions" are not going to fly with the end user.

More details: This is a combination of building controls and gas/smoke detection systems integrated together. All of the wiring is 18ga or less carrying no more than 24v at probably less than 2 or 3 amps max. Some wires are for power, some are for 4-20ma signals, and some are for contact closures.

Thanks again.

 

[rbalex]

Thank you in advance for any help provided. The situation I am dealing with involves a class 1 div 2 building in which we have quite a few devices that need to utilize liquidtight or something similiar. The manufacturer, upon our request, said that liquidtight by itself would be adequate to run from the rigid pipe to the device (2-3 feet), taking into consideration these devices are at least class 1 div 2 rated. Since then we have been told otherwise. When I look over the 2014 edition of the NEC I feel as though we should be able to use liquidtight as is. At worst I get the impression that a bonding jumper may be required. Some educated input would be great at this point. My "assumptions" are not going to fly with the end user.

More details: This is a combination of building controls and gas/smoke detection systems integrated together. All of the wiring is 18ga or less carrying no more than 24v at probably less than 2 or 3 amps max. Some wires are for power, some are for 4-20ma signals, and some are for contact closures.

Thanks again.

LFMT (liquidtight flexible metal conduit, Article 350) with listed fittings is generally an acceptable wiring method where flexibility is required in Class I, Division 2 [Section 501.10(B)(2)(4)].

The installation must also be consistent with Section 501.30. Your "More details" indicates some of the LFMT may not need additional bonding.

Seals [Section 501.15(B)] may also be required for some of the devices "... at least class 1 div 2 rated" or not.

 

[Dan LV]

Thank you for the confirmation. Everything you mentioned is pretty well on point with what I understood the code to say. The seals part I did not look into. Here is the section that explains their Class 1 Div 2 compliance:

North America ? Class 1 Division 2
The detector has been independently certified as compliant for Class 1 Division 2 operation to the relevant US (ANSI/NFPA 70 National Electrical Code, Article 500) and Canadian (CSA 22.1 Canadian Electrical Code, Annex J) standards under the following restrictions.
Rating
Class 1, Division 2,
Groups A B C & D T4
-4?F ? TAMB ? +131?F

Conditions of Use
WARNING : Exposure to some chemicals may degrade the sealing properties of materials used in the following devices.

Relays/Relais RLY1, RLY2, RLY3 and RLY4

WARNING : Explosion hazard. Do not disconnect while the circuit is live or unless the area is known to be free of ignitable concentrations
WARNING : Substitution of the following components may impair suitability for Division 2 :

Relays/Relais RLY1, RLY2, RLY3 and RLY4

Terminal Blocks/Blocs de jonction SKT1 and SKT2
Fuse/ Fusible F1
Battery Holder B1
Jumper LNK2
SD Card Socket/Carte SD Socket SKT5


So you think I need seals at the device side only then? All of the devices are of the same type as listed above, but the area is not required to be explosion proof as I understand it (isn't that class 1 div 1?). What would determine for certain that seals are needed?

Thanks again.

 

[rbalex]

Where a manufacture claims a product "... has been independently certified as compliant for Class 1 Division 2 ..." I seriously doubt it for two reasons. One, they haven't identified who the "independent certifier" is. Two, they aren't using proper terms where they should know better; i.e., it is Class I, not Class1. See the Title of Article 500 and various other examples throughout Articles 500 to 516. (I didn't necessarily expect you to know better - but I bet you will from now on )

Explosionproof equipment may be required in Division 2; especially where the product may have arcing, sparking or high temperatures. See Sections 501.15(B)(1) and 501.105(B)(1) for example

 

[gadfly56]

We've used the Crouse-Hinds flexible couplings (ECGJH series) which are available in lengths from 4" - 36" and trade sizes 1/2" to 4". They are, however, freaking expensive. And their definition of "flexible" is somewhat generous. A 4" lenght of 3/4" is just about as stiff as EMT. I don't ever use less than 18".

 

[rbalex]

... They are, however, freaking expensive...

And totally unnecessary in the OP's case.

 

[Dan LV]

Thank you guys for the comments! Despite how long it's taken me to reply I am very interested in getting this job resolved correctly. And yes, you are correct that I didn't realize the discrepencies between the 1's and the I's, etc. The products are of British origin so they may not care to put as much emphasis on "proper terminology" across the pond. Either way I see your point. As for the "not so flexible" Crouse-Hinds couplings, the cost is the reason we were trying to stay away from them. If we just needed a couple of them it wouldn't be so bad.

So do you think that regardless of the voltage/amperage the relays are switching conduit seals will be needed? And if they are needed would they just be needed at the device?

To sum up the way I am understanding this, we are currently transitioning from rigid to liquidtight, then we should add a seal, then the device. Should this be in compliance considering the information I have provided? If we have to add additional parts and pieces please clue me in since the process is starting in a few days. This kind of stuff has been very difficult to find accurate answers on! You guys have been very helpful and I appreciate it. If there is any other info that will help out I will see what I can do.

 

[don_resqcapt19]

If the device has an explosion proof enclosure and if the enclosure contains arc producing contacts, then unless the contacts are "factory sealed", the enclosure will require a seal off fitting.

 

[rbalex]

From the manufacture's description, I suspect the product isn't explosionproof, but uses an encapsulated ("Zone" Type "Ex m") protection technique or, in "Division" terms, it's hermetically sealed. Several of the product "WARNINGS" would also give me cause me great concern; especially, "Exposure to some chemicals may degrade the sealing properties of materials used in the following devices."

There is still an absence of a National Recognized Testing Laboratory's (NRTL) certification. I don't know of any competent AHJ that would accept it without NRTL certification; FedOSHA definitely wouldn't.

 

[Dan LV]

That's good to know. We have a good starting point to hopefully get this project resolved. Also knowing what is needed for the next phases beforehand is golden. Thanks again everybody for helping clear things up for me!

 

[rbalex]

Looks like we were responding at the same time. The device isn't required to be explosionproof. But it is required to be NRTL certified.

 

[Dan LV]

Hmmm.... Well, I don't know exactly how to proceed I guess. So I need to verify NRTL certification in order for this installation to be code compliant?

The environment we're dealing with is class I div II due to the potential for alcohol in the air. These devices detect for said alcohol in the space that they are supposed to be rated to be installed in. It would be sad if the certifications were not in order for the required environment!

 

[rbalex]

Hmmm.... Well, I don't know exactly how to proceed I guess. So I need to verify NRTL certification in order for this installation to be code compliant?

The environment we're dealing with is class I div II due to the potential for alcohol in the air. These devices detect for said alcohol in the space that they are supposed to be rated to be installed in. It would be sad if the certifications were not in order for the required environment!

You will need NRTL certification in order to get AHJ acceptance. Several NRTLs (UL, INTERTEK/ETL, FM, etc.) can provide field certification service. The price may be prohibitive. Of course, prohibitive is a relative term.

New question: If you have already otherwise designed/installed for Division 2 (not II, BTW) what do you believe detecting the alcohol will achieve? Combustible gas detection is another recognized protection technique [Section 500.7(K)], but it has it's own set of hoops to jump through.

 

[Dan LV]

As for the NRTL requirement they do reference UL as in the following, but once again the "independently verified.." tag.

"has been independently tested to verify full compatibility with (The parent controller these detectors connect to) without infringing associated performance approvals e.g. EN54-20 and UL 268"

And from a white paper:

"Approvals​

Electrical safety:​

Conforms to ANSI/UL Std 61010-1Certi​

​

​

​

fi ed to CAN/CSA Std C22.2 No.61010-1EN 61010-1​

EMC:​

FCC 47CFR Part 15B class BICES 003EN 50270​

Hazardous Location:​

ETL approved to ISA12.12.01,CSA C22.2 No. 213Class I Div 2 Groups ABC&D T4​

-4?F ? Tamb ? +131?F"


To answer your question "what do you believe detecting the alcohol will achieve?", well that's the whole point of this install- for gas detection. That is what we have been hired to do. The levels are monitored and notifications are triggered based on reaching certain values. The air is circulated differently based on reaching certain values, as well as some other functions that we accomplish depending on these values. Does this clarify things?

 

[don_resqcapt19]

There is nothing there that indicates that the device has been listed and tested by a Nationally Recognized Testing Laboratory.

 

[rbalex]

"Conforms to ANSI/UL Std 61010-1, Certified to CAN/CSA Std C22.2 No.61010-1 EN 61010-1" AND "ETL approved to ISA12.12.01,CSA C22.2 No. 213..." are pretty much meaningless in the US without the respective NRTL organization's certification mark on the products. Otherwise, you simply have the manufacturer's claim. While such a claim is common in the EU and generally acceptable, (that's essentially what a "CE" mark is) this isn't sufficient in the US.

NOTE: not all NRTLs are qualified to certify Hazardous Location equipment.


​

As I mentioned, combustible gas detection systems have their own set of issues. See Section 500.7(K). Read it, the Informational Note references and the Subsections for specific requirements.

That said, if you can successfully get past the NRTL and gas detector installation issues, LFMC is fine and field installed equipment seals are not likely to be required. BTW seals would not necessarily solve any issues unless the enclosures were also explosionproof. (It doesn't do much good to seal a non-explosionproof enclosure)

Depending on the overall installation you may need some boundary seals. [Section 501.15(B)(2)] They probably won't be much of an issue.

 

[Dan LV]

Ok, now we're getting somewhere. The information you guys provided gave me the inclination that I needed to look at the devices themselves. You see, I am an hour away from the site and I have been scouring through documentation that I have. So after our company left tonight I pulled up some older pictures from the site. With the more detailed info printed on the devices label I discovered the certification was from Intertek. The following is from the Intertek site, directly referencing these devices:

First Entry>

"Title:

ELECTRICAL EQUIPMENT FOR MEASUREMENT, CONTROL & LABORATORY USE"

"Evaluated to the following:

A representative sample of the listed devices have been tested, investigated and found to comply with the requirements of the Standard(s) for Electrical Equipment for Measurement, Control & Laboratory Use; Part 1 General Requirements (UL-61010-1) and are identified with the ETL Listed Mark."

Second Entry>

"Title:

NON-INCENDIVE ELECTRICAL EQUIPMENT FOR USE IN CLASS 1, DIVISION 2, HAZARDOUS (CLASSIFIED) LOCATIONS"

On the device itself there is a "c(ETL)us" mark with "listed" at the base of the circle and "Intertek" below that. It's odd to me that this information is not found in the product documentation. It sure would be helpful and save some time to have things compiled in one place. Under the assumption that this is considered a valid NRTL certification and acknowledging that your earlier comment (Bob) about an "encapsulated" device is accurate, just where do I stand now? Let me add that I did look over the 500.7 section after you mentioned it the first time, but was not clear on what it meant for me. Now I realize the device falls into the 500.7(H) category and being a non-incindive component should negate the need for anything more than the liquidtight....to the best of my comprehension at least. This is a valuable learning experience that I am soaking in for present and future use so please correct me if I am wrong. It is starting to click a bit though. Thank you all again!

 

[rbalex]

Nonincendive looks good. So does the "c(ETL)us" mark.

One more potential issue that I overlooked from your response in Post #14. It sounds like the operation expects alcohol to be present at various levels during normal operation. You might want to review Section 500.5(B)(1)(1) carefully.

 

[Dan LV]

Good point. While looking over stuff you suggested earlier I read through that also. This environment, "under normal operating conditions" is suppose to be free of any ignitable level of anything. The reason for the gas detection is the same as the reason for the smoke detection (we also are installing) generally speaking- to detect hazardous conditions in the rare event that something could possibly happen. There are alcohol based liquids stored in sealed containers within the facility, but a leak in one container would be such a small amount for the space. It also would be discovered fairly quickly both by visual and electronic aid. There will be no "open air", flamable anything in this space.

 

[Dan LV]

To clarify, we only look at different levels just in case. If the levels rose to a certain percent LFL we would transition dampers so that inside air gets mixed with outside air, thereby diluting and bringing down the LFL%. The levels aren't in place as an expectation, just a safety net.