Romex connector on a Classified A/C unit

[electrical dept]

Hope somebody can help me find the NEC code reference to see if you can/can't use a romex connector on a explosion proof A/C?

We build blast resistance buildings and inside the A/C unit there's low voltage control wires going through a romex connector that's screwed in a seal off fitting.

 

[rbalex]

This is fairly simple. Types NM, NMC and NMS wiring methods are not permitted in hazardous locations. [Sections 334.12(A)(10) and 501.10]

And before anyone attempts to play the nonincendive or intrinsically safe cards ? it ain?t gonna happen for controls to an AC unit without a manufacturer's control drawing.

 

[electrical dept]

This is what I'm asking about, that's on the exterior of the unit next to the fan motor you can clearly see the romex connector still with the lock nut on.
I'm in the Electrical Dept. and I'm not doubthing your answer I just want to get as much information as I can so that I can let my colleges from the A/C Dept. know.

 

[petersonra]

Is this part of the unit?

or something added later?

my understanding is that on cable seals you do not have to use any special part to hold the cable in the end.

in any case, UL does not list any seal as suitable for use with cables anyway so it is up to the manufacturer to tell you what can and what cannot be used.

 

[Dennis Alwon]

I will premise this statement with I don't know anything about this, however it would seem strange that a seal off is required yet you can enter it with a non sealing connector. Is one side-the side with the connector - not under the same rules as the other side of the fitting?

 

[rbalex]

I stand by my original post. I guarantee the cable shown isn't acceptable in any Class I, location whether the connector used with it is listed for that particular cable or not.

 

[petersonra]

I stand by my original post. I guarantee the cable shown isn't acceptable in any Class I, location whether the connector used with it is listed for that particular cable or not.

is the cable shown by any chance on the non-hazardous side and this is the boundary seal?

the other side appears to be rigid so maybe that side is headed into the classified area and the cable we see is not in the classified area.

 

[rbalex]

Then last but not least, the locknut scheme doesn't comply with 501.30(A). This is a noncompliant installation.

 

[petersonra]

Then last but not least, the locknut scheme doesn't comply with 501.30(A). This is a noncompliant installation.

if the seal is not in a hazardous location why would the clamp have to comply with 501.30(A)?

I don't like it, but I am am also reaching for some reason it might be OK.

 

[jeremysterling]

It appears to be a nicely executed factory assembly to me. I did similar stuff with pirelli cable entrance to devices and metering equiopment for propane and natural gas powered 6MW gensets. We used cgb's, but if I was making a window unit instead of a six meg genset, I think any old cable clamp would be fine. The locknut is keeping the orientation of the clamp square to the skid.

 

[rbalex]

You cannot use a locknut-bushing in the ground path - even in the unclassified location.

 

[GoldDigger]

You cannot use a locknut-bushing in the ground path - even in the unclassified location.

Since the cable inside the nylon sheath appears to be flexible cord, or at least non-metallic, what makes you think that the locknut is in the grounding path for anything? Or are you just worried about the clamp itself being bonded to the fitting?

 

[rbalex]

Since the cable inside the nylon sheath appears to be flexible cord, or at least non-metallic, what makes you think that the locknut is in the grounding path for anything? Or are you just worried about the clamp itself being bonded to the fitting?

You may have me there. However, I can't identify any grounding/bonding means at all since it appears that they are actually single conductors in an automotive wiring loom that wouldn't ordinarily be an acceptable wiring method under any condition except as complete manufactured equipment. In which case I'd like to know which part of FedOSHA 29CFR1910 399 or some State OSHA would find it Acceptable.

 

[petersonra]

You may have me there. However, I can't identify any grounding/bonding means at all since it appears that they are actually single conductors in an automotive wiring loom that wouldn't ordinarily be an acceptable wiring method under any condition except as complete manufactured equipment. In which case I'd like to know which part of FedOSHA 29CFR1910 399 or some State OSHA would find it Acceptable.

I asked previously if this is part of the equipment or not? It seems to me if it is part of the equipment, it may well be listed, making it more or less automatically acceptable.

This kind of wiring is very common as part of a piece of manufactured equipment.

It does seem very odd to me though that it could be part of a piece of gear designed for use in a classified area.

 

[rbalex]

We started with a simple question of about ROMEX? connectors in a classified location. Simple answer: NM isn?t compliant with classified locations so their connectors aren?t either.

OP author responds with a photo and all sorts of speculation ensued. I was guilty too with regard to the grounding issue. However, since the photo the OP author has not clarified the application.

Allowing that it is factory installed wiring, unless it is definitively NOT in a classified location I can?t see how it is either acceptable under FedOSHA or suitable under NEC Section 500.8(A)

Under FedOSHA 29CFR1910 399:

Acceptable
An installation or equipment is acceptable to the Assistant Secretary of Labor, and approved within the meaning of this Subpart S:

(1) If it is accepted, or certified, or listed, or labeled, or otherwise determined to be safe by a nationally recognized testing laboratory recognized pursuant to ? 1910.7; or

(2) With respect to an installation or equipment of a kind that no nationally recognized testing laboratory accepts, certifies, lists, labels, or determines to be safe, if it is inspected or tested by another Federal agency, or by a State, municipal, or other local authority responsible for enforcing occupational safety provisions of the National Electrical Code, and found in compliance with the provisions of the National Electrical Code as applied in this subpart; or

(3) With respect to custom-made equipment or related installations that are designed, fabricated for, and intended for use by a particular customer, if it is determined to be safe for its intended use by its manufacturer on the basis of test data which the employer keeps and makes available for inspection to the Assistant Secretary and his authorized representatives.(Underline is mine)

State Plan States must be at least as rigorous or FedOSHA trumps.

NEC Section 500.8(A) Suitability is sort of a quick and dirty summary of the above.

(A) Suitability. Suitability of identified equipment shall be determined by one of the following:
(1) Equipment listing or labeling
(2) Evidence of equipment evaluation from a qualified testing laboratory or inspection agency concerned with product evaluation
(3) Evidence acceptable to the authority having jurisdiction such as a manufacturer?s self-evaluation or an owner?s engineering judgment.

Note the FedOSHA rules are still more rigorous than the NEC. When the NEC TCC balked at clarified definition of identified as applied to Classified locations, I helped develop what is now Section 500.8(A) while part of the API SOEE.

 

[CSFULMER9]

I am the manufacturer fo the product in question. This is part of the internal wiring of the equipment done by the manufacturer. This does meet NEC requirements and is in the classified location. The loophole for this to meet NEC is the romex connector is not being used in any other way other than vibration isolation. This is the condenser section of the equipment near the fan. As with any air conditioner this area will have tremendous amount of vibration over the units life.

Also CSA has approved this application.

 

[BPoindexter]

I am the manufacturer fo the product in question. This is part of the internal wiring of the equipment done by the manufacturer. This does meet NEC requirements and is in the classified location. The loophole for this to meet NEC is the romex connector is not being used in any other way other than vibration isolation. This is the condenser section of the equipment near the fan. As with any air conditioner this area will have tremendous amount of vibration over the units life.

Also CSA has approved this application.

So is it CSA UL listed/labeled? What Area/Division is it listed for?

If it is for vibration protection why wouldn't you use a CGB or similar rather than a Romex connector? And why leave the locknut on the connector vs. screwing it in wrenchtight? It can only have maybe a couple of threads in engaged in that configuration. I believe that at the very least this is a violation of 110.3(B) as this is not the intended use of the connector.

As far as grounding/bonding if a wire shorted to the connector itself, not implausible, then the fault path would be through the connector threads to the seal to the nearest bonded point. I suggest the loophole you mentioni above is non-existent.

 

[rbalex]

So is it CSA UL listed/labeled? What Area/Division is it listed for?

This is absolutely the right question. If it isn't CSA-UL then is isn't NRTL certified.

 

[jumper]

This is absolutely the right question. If it isn't CSA-UL then is isn't NRTL certified.

Good point, I approved the post so the manufacturer could answer such questions.

Now I am leaving, I basically know squat about hazardous locations, only worked in one. A Transco pipeline pump station.

Oh what fun.:happysad:

 

[rt66electric]

is the picture oriented correctly horizontal? vertical?

is the picture oriented correctly horizontal? vertical?

Has any body noticed that the seal-off is turned the wrong way??

The only time that I have seen a seal-off that clean, is when it was empty.