ground lug and ground wire in class1 div2 enclosure

[hysteresis]

I am using a clx cable (type MC-HL XHHW-2) terminated at the class1 div2 SS enclosure with a class1 div2 cable gland. The cable consists of 3 insulated wires plus a bare copper wire. My question is : can this bare wire be used inside the rated enclosure and be connected to the panel ground or to a copper/brass ground lug? Does this violate the class1 div2 rating? If so, then why is the MC-HL rated for use in class1 div2 environments? thank you

 

[rbalex]

As long as it is sized properly [Section 250.122], the bare copper conductor is permitted to be the equipment grounding conductor.

ANY MC is acceptable in Class I, Division 2. [Section 501.10(B)(1)(6)] MC-HL is a special construction for Division 1 which automatically makes it suitable for Division 2. [Sections 501.10(A)(1)(c) & 501.10(B)(1)(1)]

 

[hysteresis]

ground lug and ground wire in class1 div2 enclosure

Robert,

Thanks for the quick reply.
Yes , the wire is properly sized as a grounding wire. I intend to connect this bare wire to the grounding lug of the enclosure's back panel ( atex type hoffman enclosure). I do have a couple of others MC cables terminating at the enclosure ( again , using class1 div2 cable glands, TMC050A), one of which is the main power cable. These cables also have a grounding wire each. Is it safe ( for class1 div2) to connect these ground wires individually to a rated wago type terminal (green, ground type) or connect all of them to a common multi terminal ground bar?
Thank you.

 

[rbalex]

ATEX means absolutely nothing in US domestic applications.

That said, inside the box, you can terminate the bare wires, just as you would in an unclassified location.

 

[hysteresis]

ground lug and ground wire in class1 div2 enclosure

Robert,
True . ATEX means almost nothing here in the US. I was looking for a class1 div2 rated SS enclosure And I couldn't find any out there. Plenty of Class1 div1 but explosion proof was not required, plus the extremely high cost for these. The closest I came to class1 div2 was a hoffman enclosure:
ATEX Directive 94/9/EC
ATEX
Sira 09ATEX3224U
Ex e IIC Gb
Ex tb IIIC Db IP 66
IECEx
IECEx SIR 09.0099U
Ex e IIC Gb
Ex tb IIIC Db IP 66
EN 60079-0:2006
EN 60079-7:2007
EN60079-11:2007
EN 61241-0:2006
EN 61241-1:2004
UL 508A Listed; Type 4, 4X, 12; File No. E61997
cUL C22.2 No. 94 Listed; Type 4, 4X, 12; File No. E61997
NEMA/EEMAC Type 4, 4X, 12
IEC 60529, IP66

After the client saw the above, he accepted that this enclosure was close to a class1 div2 one. I had the same problem locating class1 div2 circuit breakers, the only one out there is STAHL but they are very hard to get here. Going back to the original question, is there a specific requirement for a ground bar for class1 div2 enclosures?

Thank you and Happy Thanksgiving.

 

[rbalex]

As I said, ATEX means ABSOLUTELY nothing in US domestic applications.

The enclosure doesn't necessarily need to be specifically "rated" for Division 2, it depends on what goes inside it. If the equipment inside the enclosure is not suitable for Division 2, then the enclosure alone will not make it suitable, ATEX ratings notwithstanding.

If you have the NEC you need to read (and understand) Articles 500 and 501 before you even attempt to decide what the enclosure should be; otherwise you need to get someone who does.

 

[hysteresis]

ground lug and ground wire in class1 div2 enclosure

Robert,

I did read the articles you mentionned. A lot of it is straightforward recommendations. When it comes to class1 ( div1 and 2) there are recommendations about components ( glands, enclosures, etc..) but not a lot about systems. Now the main difference between nema4x and class1 div2 is the ability for the latter to offer a shield from eventual gases under abnormal conditions., where 4x provides insulation from corrosives atmospheres, amongst other things. Now, there are no control panels that are rated class1 div2 unless all the components are either IS or class1 div2 rated, and yes the rating of the enclosure has to be approved for such environments. In my project, the selector switches ( Allen bradley, 880H series), the breakers (Stahl), cables (MC-HL), cable glands (C1 D2) are all rated class1 div2. The control panel is to be located on an offshore platform, thus the required rating. Most people avoid this by simply purchasing a very expensive class1 div1 enclosure and throwing in unrated components.
One final note, in the US the ATEX rating is useless. But if you do business worldwide, class1 div2 and sometimes class1 div1 is not accepted, especially in Europe . ATEX is required there.
I thank you for you help and your interesting comments.

 

[rbalex]

The reason you have had trouble finding specifically marked Division 2 enclosures for your application is they don't exist. I suggest you reread Section 500.8 carefully. It appears to me that you are attempting to apply IEC/CENELEC/ATEX Zone rated products and practices to a US domestic installation. Even if you were using Article 505 (Zones), they don't apply. The IEC/CENELEC/ATEX marks are all irrelevant.

If the internal components are suitable for Division 2, the enclosure doesn't need to be specifically marked for Divison 2. The enclosures aren't required to "... offer a shield from eventual gases under abnormal conditions..." in NEC Division 2 locations. For that matter, the enclosures aren't required to in Division 1 or IEC/CENELEC/ATEX applications either. Some of the internal components may, but not the overall enclosure.

I'd sure like to see the certification markings on that Stahl breaker.

 

[hysteresis]

ground lug and ground wire in class1 div2 enclosure

Robert,

Here is the Stahl's breakers spec sheet:
http://www.rstahl.com/fileadmin/Dateien/tgus/Documents/FRP-PDF-11-16-09.pdf

Also, the selector switches are Allen Bradley 800H series ( not 880).
I did mention in a previous post that C1 D2 enclosures do not exist as such, although some manufacturers claim that. Most of my installations are overseas and I am having trouble convincing the inspectors there about the class/atex/whatever rating. I did an installation not long ago here in the US, and as your post suggested, the enclosure did not have to be C1 div1 or 2, but I supplied a nema4x enclosure with C1 D2 internal components and it passed inspection. Again it was for an offshore platform. Each country overseas has its own certification body and most of the time they require ATEX.
Anyway, the reason for my initial post was since I am using components that are rated Class1 Div2, the fact that the grounding wire was bare seemed out of place. Your answers are logical and they lead me to conclude that the grounding lug/bare wire is /are not an arc producing terminal/component and therefore it/they can be used inside such enclosures. (unless it is in a class1 div1 zone). Is this correct?
Thanks again for your patience.

 

[rbalex]

A manufacture claiming that their "ordinary location" enclosure, is suitable for Division 2, is most likely telling the truth - even if it isn't marked for it. See Sections 500.8(B)(3) and 500.8(C)(6)(a).

The FM certification (Class I, Zone 1, AEx de IIC) on the Stahl breakers is fine. I was just curious what protection technique they were using. They are certifying the breaker, apart from the overall enclosure, is itself "flame proof" (conceptually, "explosionproof") and "increased safety." NEC Section 501.5 recognizes the breakers as suitable for Division 2. "Increased safety" doesn't mean anything in Articles 500 & 501, but is a nice feature in my opinion. Getting ratings for Groups A & B for Divisions is impressive; then again that's why UL isn't certifying them, but CSA does. Canada is much more in tune with the international standards.

Everything else looks good to go. Grounding/bonding in both US Divisions and Zones can be a bit confusing. The rules for Divisions [Section 501.30] and Zones [Section 505.25] are the same - even in explosionproof enclosures. Actually, it's one of the places that Zone "Increased Safety" is a nice feature - but not required in Division classified locations.

 

[alaskanoilelectrician]

Should have read the entire posts but thought id tell you a little you may already know.
MCHL stands for metal clad hazardous location. this type oil cable is used widely in the oil field. Some of the characteristics that make it
legal to use in Class 1 Div. 1 locations in that it is corrugated CONTINUOUS WELDED.
There are also TMCX cable terminator cable glads. They are the cable glads for use on this type of cable. They always or almost always
have a red ring on a portion of the connector to distinguish it from a regular MC connector for use on MC cable with the PVC jacket over
the exterior of the cable. Also the TMCX type cable gland connector will have a two part putty type material used to prevent migration of
gasses into the enclosure that this cable is connected to.
I know that this is more info than you asked for and not even answering your question but I thought you might find it interesting.
Also this cable will also use parallel ground wires in order to get the proper size equipment grounding conductor. This is quite common for this type of cable . Also another type cable that uses this cable construction is type GGC cable which is a type of cord also used often in the mining industry. All of which is quite legal and in some cases above and beyond code requirements.
Hope I didn't bore you with this?
PS pardon my grammar