cable glands in a z purged enclosure

[kchap]

Hello everyone. Is it acceptable to use general purpose cable glands for intrinsically safe cable entry into a Type 4X, Z-purged enclosure? Or do the glands need to be rated for the area outside the enclosure (C1D2 in this case)? Exception No. 1 of 501.15(E)(1) allows installation without seals, and 504.70 does not require explosion proof seals for IS circuits. I am tempted to think that general purpose cable glands would be OK, but my gut tells me this is wishful thinking.

 

[rbalex]

This appears to be a belt and suspenders (and possibly bailing wire) installation; however, to answer your question, a general purpose cable connector is fine. It should simply be listed for terminating the cable Type.

 

[kchap]

I am relatively new to hazardous location work and am doing the best I can to understand article 500. If I come here for advice or clarification, I would appreciate constructive criticism if I post a question that betrays my ignorance. If the installation appears to be "belt and suspenders (and possibly bailing wire)", please tell me why. At any rate, I do appreciate your response, Bob.

 

[rbalex]

Basically, intrinsically safe systems (IS) do not need a Type Z purge in addition or vice versa. (Belt and suspenders) In fact, in Class I, Division 2 neither are usually needed, but could be depending on what is actually in the enclosure (possibly baling wire). I genuinely apologize for belittling you.

IS is usually a Division 1 protection technique. If used at all, Division 2 will use a nonincendive protection technique. See Section 500.7 for various other potential protection techniques.

 

[kchap]

No worries, Bob. Now I see where you were coming from. You were simply responding to the minimal information I provided.

There are other items in the panel that require it to be purged. The only IS components are the thermocouples, which do need to be intrinsically safe because of their location. The equipment has been evaluated as C1D1 up to 18 inches above the floor and C1D2 above 18 inches (the control panel is above this boundary).

I do have another question that I feel somewhat embarrassed about needing to ask... Can the control drawing for the thermocouples and IS barriers be a part of the panel drawing package, or does it need to be a separate item? Is it sufficient if the I/O drawings show the connection points and their locations relative to the boundary between the unclassified interior of the panel and the rated area outside?

 

[petersonra]

There is no reason you cannot add the control drawing to your drawing package. It might even be a good idea just to make sure everything is in one place. Normally I would put manufacturers drawings like that in a binder with the other manufacturers manuals but you can handle it however you want. These days the drawings are likely to be on a CD so they don't even get binder anymore.

 

[nec_addicted]

Ignition Control C1D2

Ignition Control C1D2

No worries, Bob. Now I see where you were coming from. You were simply responding to the minimal information I provided.

There are other items in the panel that require it to be purged. The only IS components are the thermocouples, which do need to be intrinsically safe because of their location. The equipment has been evaluated as C1D1 up to 18 inches above the floor and C1D2 above 18 inches (the control panel is above this boundary).

I do have another question that I feel somewhat embarrassed about needing to ask... Can the control drawing for the thermocouples and IS barriers be a part of the panel drawing package, or does it need to be a separate item? Is it sufficient if the I/O drawings show the connection points and their locations relative to the boundary between the unclassified interior of the panel and the rated area outside?

"Minimal information" - is exactly the context in this and other replies. With that in mind possibilities of pipeline -LP Gas or LPG- the original post probability research at his 'list of deliverables' for documentation requiremenuts and/or Normalative reference specifications ' such as NFPA 58:6.22.1 and or NFPA 59 Chapter 4 (4.5) Ignition Source Control :by the by 49 CFR 192 might suffice as consideration-above intended as comment only.

 

[rbalex]

I'm going to concur with petersonra's recommendation. I'm not sure what nec_addicted is attempting to convey.

I am curious what standard was used to develop the original electrical area classification; it is a highly unusual.

 

[nec_addicted]

I'm going to concur with petersonra's recommendation. I'm not sure what nec_addicted is attempting to convey.

I am curious what standard was used to develop the original electrical area classification; it is a highly unusual.

I intend to convey the idea the OP wrote C1D2 18" off the floor and C2D1 below that figure. That is the conundrum with "highly unusual" especially with mechanical ventilation.
So consequently I do not believe the other equipment obey that boundary limit. The codes I speak of NFPA 59 and NFPA 58 are LP Gas Plant and tables for equipment in the area for valves and equipment flanges.
Normal class and boundaries in API RP500C or AGA (American gas association) defined in proximity to equipment.
Doing as proposed is against those normal specfivations so I pointed at Normalative References.
Why is that such a mystery?

 

[rbalex]

I intend to convey the idea the OP wrote C1D2 18" off the floor and C2D1 below that figure. That is the conundrum with "highly unusual" especially with mechanical ventilation.
So consequently I do not believe the other equipment obey that boundary limit. The codes I speak of NFPA 59 and NFPA 58 are LP Gas Plant and tables for equipment in the area for valves and equipment flanges.
Normal class and boundaries in API RP500C or AGA (American gas association) defined in proximity to equipment.
Doing as proposed is against those normal specfivations so I pointed at Normalative References.
Why is that such a mystery?

You do realize API 500C is no longer viable (and hasn't been since 1991) and AGA XF0277 is not ANSI; however, none of the Standards you cited quite lend themselves to the envelope conditions cited in Post #5.

 

[nec_addicted]

No worries, Bob. Now I see where you were coming from. You were simply responding to the minimal information I provided.

There are other items in the panel that require it to be purged. The only IS components are the thermocouples, which do need to be intrinsically safe because of their location. The equipment has been evaluated as C1D1 up to 18 inches above the floor and C1D2 above 18 inches (the control panel is above this boundary).

I do have another question that I feel somewhat embarrassed about needing to ask... Can the control drawing for the thermocouples and IS barriers be a part of the panel drawing package, or does it need to be a separate item? Is it sufficient if the I/O drawings show the connection points and their locations relative to the boundary between the unclassified interior of the panel and the rated area outside?

Certainly "rated area outside" in post #5 makes it an area of discussion. Publication dates reffered to do not automatic make them non compliant unless of course "original area classification" in your intention has a crystal ball knowing the construction package for these facilities.

 

[rbalex]

Certainly "rated area outside" in post #5 makes it an area of discussion. Publication dates reffered to do not automatic make them non compliant unless of course "original area classification" in your intention has a crystal ball knowing the construction package for these facilities.

OK, let's take it from a different angle. Have you ever seen such a classified location and what was the basis? Citing irrelevant Standards as you did in Post #9 doesn't make a compelling argument.

 

[nec_addicted]

Classification NEC 500.4

Classification NEC 500.4

Certain National Electric Code 2014 500.4 B informational note no. 4 specifies ANSI/ API RP 500-2012.

 

[rbalex]

Certain National Electric Code 2014 500.4 B informational note no. 4 specifies ANSI/ API RP 500-2012.

Yes - So? (I was an author/editor of the three previous Editions) It still doesn't support the classification description from Post #5.

 

[petersonra]

The 18in thing sounds like something someone saw in the garage article. Seems to me there's a breakpoint at 18 in there. I don't have easy access to the code at home so I can't look it up so maybe it's something I'm remembering funny since I don't get into that stuff much anymore.

 

[nec_addicted]

Experience with Partitioned Sealed Floors and Walls

Experience with Partitioned Sealed Floors and Walls

Primarily there are zero reasons to use post#5. Generally the only prevalence for the "18" above floor as C1D2" (and below as C1D1) are bathtub design where trenches are on all gas compressor elevations and conduits are in the trenches shared with Class 2 and Class 3 liquefied petroleum product or fuel gas. There some equipment OEM mount their NEMA 12 local panels with C1D2 PLC and other controls.

Of course the illustration in NEC 2014 exhibit 500.1 shows a 3 foot rise instead of 18" as described and there must be continuous ventilation at a certain CFM to reach this boundary described some in post #5.

It is required for AH to have recorded industrial experience as in 500.4 informational note 1. Where this is unacheviable the AHJ is allowed to issue certification permits to deal with help in Construction Packaged Drawings to work with SFMO ( state fire marshal office plan reviewers).

I mentioned brief information because this was opening day for MLB and I for one believe we should wait for OP to send a message. This might very well be Off Shore as in ANSI /API 14F or ISA.
In that consideration a safety board including administrative law enforcement will have the call on this one.
I completely do not believe he (OP) can "do whatever he wants" in Petersona post you endorsed.

 

[rbalex]

The 18in thing sounds like something someone saw in the garage article. Seems to me there's a breakpoint at 18 in there. I don't have easy access to the code at home so I can't look it up so maybe it's something I'm remembering funny since I don't get into that stuff much anymore.

There are several 18" or 24" from grade conditions that are Division 2. Usually Division 1 fills up the whole enclosed space unless it's well ventilated and then it is back to Division 2 with a few possible Division 1 envelopes measured from the source, but not grade.

 

[nec_addicted]

Extent of Class 1 Division 2 for 550 PSIG Natural Gas

Extent of Class 1 Division 2 for 550 PSIG Natural Gas

rbalex: rather the provision you champion in this forum previously seem to be a clearer definition of what is expected.
Post #5 above does not carry the virtual definition you achieved previously.
Please accept your previous thread as a definitive course of discussion with title 550 PSIG gas.

 

[kchap]

This project is for a small ethanol distilling process skid. The actual amount of ethanol in the process is small...a couple of gallons at most. Since ethanol vapor is heavier than air, it would tend to settle near the floor. Also, the pumps for the process are located near the floor. That was the reasoning for the C1D1 classification below 18 inches.

 

[kchap]

I forgot to add... The skid will be located in an enclosed space that is ventilated.