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Wait, I suppose you could just change the clamp to one that would give them more breathing room.

Back to the original concern. Should some corrective action be taken or are they ok as is?

That fastener isn't meant to be used with NM cable.

Is that the only one or are there others?

- Jim Katen, Oregon

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Wait, I suppose you could just change the clamp to one that would give them more breathing room.

Back to the original concern. Should some corrective action be taken or are they ok as is?

That fastener isn't meant to be used with NM cable.

Is that the only one or are there others?

- Jim Katen, Oregon

Thats the only one I could see. The majority of the runs were passing through the I-joist webs. The holes in the webs were large enough to allow some breathing room.

Thanks for the quick response Jim.

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  • 2 weeks later...

In the picture you see a bundle of AWG14. The spot where they pass through the clamp support is where they are the tightest. Should these wires be de-rated due to this arrangement?

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tn_20091211182551_HPIM1530.jpg

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The is a clamp for copper tubing. To hell with 110.3(B) listing and labeling.

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In the picture you see a bundle of AWG14. The spot where they pass through the clamp support is where they are the tightest. Should these wires be de-rated due to this arrangement?

Click to Enlarge
tn_20091211182551_HPIM1530.jpg

50.38 KB

The is a clamp for copper tubing. To hell with 110.3(B) listing and labeling.

I guess that you do not think that 334.30 is being met be this? Where does it say in 334.30 that the fitting must be listed? This cables are secured and it does not look like they are being damaged by this clamp. What part of Article 300 would this usage violate?

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In the picture you see a bundle of AWG14. The spot where they pass through the clamp support is where they are the tightest. Should these wires be de-rated due to this arrangement?

Click to Enlarge
tn_20091211182551_HPIM1530.jpg

50.38 KB

The is a clamp for copper tubing. To hell with 110.3(B) listing and labeling.

I guess that you do not think that 334.30 is being met be this? Where does it say in 334.30 that the fitting must be listed? This cables are secured and it does not look like they are being damaged by this clamp. What part of Article 300 would this usage violate?

334.30 Securing and Supporting. Nonmetallic-sheathed

cable shall be supported and secured by staples, cable ties,

straps, hangers, or similar fittings designed and installed so

as not to damage the cable, at intervals not exceeding 1.4 m

(41#8260;2 ft) and within 300 mm (12 in.) of every outlet box,

junction box, cabinet, or fitting. Flat cables shall not be

stapled on edge. Sections of cable protected from physical damage by

raceway shall not be required to be secured within the

raceway.

It is a pipe hanger. It is not designed for electrical wiring. Show me the listing requirements in the UL White Book for using this product to support NM cable. It is not there. It violates 110.3(B).

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Show me where it is required that the support be listed.

110.2 Approval. The conductors and equipment required

or permitted by this Code shall be acceptable only if

approved.

100

Approved. Acceptable to the authority having jurisdiction.

110.3 Examination, Identification, Installation, and Use

of Equipment.

(A) Examination. In judging equipment, considerations

such as the following shall be evaluated:

(1) Suitability for installation and use in conformity with

the provisions of this Code

FPN: Suitability of equipment use may be identified by a

description marked on or provided with a product to identify

the suitability of the product for a specific purpose,

environment, or application. Suitability of equipment may

be evidenced by listing or labeling.

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Show me where it is required that the support be listed.

110.2 Approval. The conductors and equipment required

or permitted by this Code shall be acceptable only if

approved.

100

Approved. Acceptable to the authority having jurisdiction.

110.3 Examination, Identification, Installation, and Use

of Equipment.

(A) Examination. In judging equipment, considerations

such as the following shall be evaluated:

(1) Suitability for installation and use in conformity with

the provisions of this Code

FPN: Suitability of equipment use may be identified by a

description marked on or provided with a product to identify

the suitability of the product for a specific purpose,

environment, or application. Suitability of equipment may

be evidenced by listing or labeling.

So using that there is no compliant method to attach a ground to a metallic box except a listed ground clip. You would not be able to use a ground screw since none are listed.

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AS an AHJ the clamp shown would be acceptable to me.

Just for fun, how about an 8d nail that was driven into the wood next to the NM and very carefully bent over until it secured the NM in place but didn't damage the sheathing? Would that be acceptable or not, and why?

- Jim Katen, Oregon

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I would accept the pipe clamp in the photo because it is plastic and wide and at no point does the metal touch the NM cable. A nail on the other hand is similar to an uninsulated metal staple. I am not a fan of uninsulated staples such as the one in the phot below the pipe clamp that is holding 2 wires. The reason I don't like metal staples is that they can be placed too tightly and damage the jacket. I have also seen the wires pulled after the metal staple was placed and it stripped the jacket back. I would think the same would happen with an 8d nail.

The pipe clamp appears to be workman like in its installation and in all realistic applications will never cause a problem. This is a reasonable installation.

I approve metal staples every day as long as they are not pinching the wires but I would not appoved a nail for the reasons above. This pipe clamp is better than a nail or an uninsulated metal staple any day. The NEC & IRC allow some subjectivity for the inspector, hence the word "approved".

Depending on the length and tightness of the bundling, this may only be a derating issue as the OP eluded to initially.

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Show me where it is required that the support be listed.

110.2 Approval. The conductors and equipment required

or permitted by this Code shall be acceptable only if

approved.

100

Approved. Acceptable to the authority having jurisdiction.

110.3 Examination, Identification, Installation, and Use

of Equipment.

(A) Examination. In judging equipment, considerations

such as the following shall be evaluated:

(1) Suitability for installation and use in conformity with

the provisions of this Code

FPN: Suitability of equipment use may be identified by a

description marked on or provided with a product to identify

the suitability of the product for a specific purpose,

environment, or application. Suitability of equipment may

be evidenced by listing or labeling.

So using that there is no compliant method to attach a ground to a metallic box except a listed ground clip. You would not be able to use a ground screw since none are listed.

250.148© reads;

© Metal Boxes. A connection shall be made between the

one or more equipment grounding conductors and a metal

box by means of a grounding screw that shall be used for

no other purpose, equipment listed for grounding, or a

listed grounding device.

Any machine screw is acceptable (they do not have to be green). It just can't be used for any other purpose.

The UL White Book reads;

Ground Clips — Ground clips are intended to be pressed on the flat surface of a square, rectangular, or octagonal box to hold a grounding conductor against the side wall of the box. Ground clips are typically used for connecting the grounding conductor of various wiring methods to outlet boxes or for connecting the bonding jumper from a receptacle or switch to an outlet box.

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Show me where it is required that the support be listed.

Mr. Port has a valid point here. Section 110.3 is one of the most misused/misunderstood sections in the Electrical Code.

Most Electricians and/or Inspectors automatically assume that everything that is installed in an electrical installation must be UL listed.

This is highly incorrect. Section 110.3 does not require the listing of electrical equipment/parts. It only states that IF equipment is listed /labeled it must be used according the listing and labeling.

So if that plastic pipe clamp,( which looks like to me it's a clamp for PVC pipe), is not listed or labeled by UL for a peticular and limited use,then it is up to the AHJ to determine the allowed usage.

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