Securing MC Cable

M

MatthewEE

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Location
Maryland
Occupation
Engineer
Is it acceptable to secure MC cable using standard wire (like ceiling grid support wire) wrapped around the MC and tied to all-thread? My read of 330.30(A) is that this is not acceptable, but interested in other opinions.
 
MatthewEE said:
Is it acceptable to secure MC cable using standard wire (like ceiling grid support wire) wrapped around the MC and tied to all-thread? My read of 330.30(A) is that this is not acceptable, but interested in other opinions.
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As long is your ahj approves the method of securement it’s compliant . If he approves a shoelace to be used as a method to secure the cable it can be used
 
MatthewEE said:
Is it acceptable to secure MC cable using standard wire (like ceiling grid support wire) wrapped around the MC and tied to all-thread? My read of 330.30(A) is that this is not acceptable, but interested in other opinions.
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If cable ties are used they have to be listed and identified to be used for securement and support, tie wire is a common method used to secure mc cable and have a hard time seeing the ahj not accepting this method
 
Tie wire will go away in the 2026 as all of the cabling wiring methods will require the use of listed supports.
Even though tie wire is often more secure than the listed products.
 
don_resqcapt19 said:
Tie wire will go away in the 2026 as all of the cabling wiring methods will require the use of listed supports.
Even though tie wire is often more secure than the listed products.
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Will it be required that the listed product used be specifically listed and identified to secure that specific cable assembly , or will the code see a product that is listed and identified as a method of securing and supporting in general like a capable tie as acceptable To support any cable assembly. For instance will staples still be seen as an acceptable method of securing mc cable if approved by the ahj?
 
infinity said:
Any idea how they came up with a suitable substantiation for this?
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For article 334 on NM cable, it was PI 2886-NFPA 70-2023 from somebody at UL. The relevant portion of the substantiation was:

"To avoid damage to Type NM cable and undue stress being transferred to electrical connections from sagging cables a requirement for listed hardware for support and securement of Type NM Cables is necessary by the NEC. The need for the NEC to require listed staples, straps, hangers and fittings became more crucial on account of advancements installation tool technology and today’s tools that provide staple depth control. The ANSI/UL Standard for Safety for Hardware for the Support of Conduit, Tubing, and Cable, UL 2239, was first published nearly 20 years ago and contains all necessary hardware construction, performance, marking and installation instructions necessary to provide installers and AHJs the guidance to properly use today’s tools to support and secure Type NM cables when using listed hardware."

The relevant portion of the panel's response to the PI was:

"New listing requirements have been added for support and securement hardware and requirements have been broken out into a list format. Support and Securement hardware need to be listed to avoid damage to Type NM and NMC cables from inadequate and untested supporting and securement methods. Using listed support and securement hardware will reduce the risk of damage and undue stress being transferred to electrical connections."

Make sure your NM staples are listed once the 2026 NEC hits!

Cheers, Wayne
 
wwhitney said:
For article 334 on NM cable, it was PI 2886-NFPA 70-2023 from somebody at UL. The relevant portion of the substantiation was:

"To avoid damage to Type NM cable and undue stress being transferred to electrical connections from sagging cables a requirement for listed hardware for support and securement of Type NM Cables is necessary by the NEC. The need for the NEC to require listed staples, straps, hangers and fittings became more crucial on account of advancements installation tool technology and today’s tools that provide staple depth control. The ANSI/UL Standard for Safety for Hardware for the Support of Conduit, Tubing, and Cable, UL 2239, was first published nearly 20 years ago and contains all necessary hardware construction, performance, marking and installation instructions necessary to provide installers and AHJs the guidance to properly use today’s tools to support and secure Type NM cables when using listed hardware."

The relevant portion of the panel's response to the PI was:

"New listing requirements have been added for support and securement hardware and requirements have been broken out into a list format. Support and Securement hardware need to be listed to avoid damage to Type NM and NMC cables from inadequate and untested supporting and securement methods. Using listed support and securement hardware will reduce the risk of damage and undue stress being transferred to electrical connections."

Make sure your NM staples are listed once the 2026 NEC hits!

Cheers, Wayne
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Don said that all wiring methods will require listed supports in 2026 not only NM cable. Is there substantiation for tie wire being banned for MC cable as per the OP?
 
infinity said:
Don said that all wiring methods will require listed supports in 2026 not only NM cable. Is there substantiation for tie wire being banned for MC cable as per the OP?
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For MC Cable, PI No. 2883-NFPA 70-2023 reads almost identical to the PI on NM cable, just with the name changed.

You could still use tie wire if UL 2239 has standards for tie wire. You'll just need to get UL 2239 listed tie wire. I'll leave it to you to check UL 2239 on what it has to say on the topic.

Cheers, Wayne
 
wwhitney said:
For MC Cable, PI No. 2883-NFPA 70-2023 reads almost identical to the PI on NM cable, just with the name changed.

You could still use tie wire if UL 2239 has standards for tie wire. You'll just need to get UL 2239 listed tie wire. I'll leave it to you to check UL 2239 on what it has to say on the topic.

Cheers, Wayne
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So you’re saying as long as it’s listed for securement and support of cable assembly the product listing is not required to identify specifically to the cable assembly being used ? Or am I misunderstanding?
 
Jaybone812 said:
If cable ties are used they have to be listed and identified to be used for securement and support, tie wire is a common method used to secure mc cable and have a hard time seeing the ahj not accepting this method
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I use bat wings for clamping to wire drops

 
Fred B said:
I use bat wings for clamping to wire drops

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Nothing wrong with that, they def work and sounds like you prefer them , but as far as making a the mc cable nearly invisible while secured to the threaded rod , bat wings juts aren’t capable of keeping as tight to the rod all the way down the as using tie wire or cable ties as far as I’m concerned
 
infinity said:
Any idea how they came up with a suitable substantiation for this?
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It was submitted by UL and the following was the substantiation:
Removal of other approved since listed hardware is being proposed in 330.2 and 330.30(A). To avoid damage to Type MC cable and undue stress being transferred to electrical connections from sagging cables a requirement for listed hardware for support and securement of Type MC Cables is necessary by the NEC. The need for the NEC to require listed staples, straps, hangers and fittings became more crucial on account of advancements installation tool technology and today’s tools that provide staple depth control. The ANSI/UL Standard for Safety for Hardware for the Support of Conduit, Tubing, and Cable, UL 2239, was first published nearly 20 years ago and contains all necessary hardware construction, performance, marking and installation instructions necessary to provide installers and AHJs the guidance to properly use today’s tools to support and secure Type MC cables when using listed hardware.
Panel Statement
...The word “staples” was relocated in the text, and now staples, hangers, straps, and similar fittings are required to be listed. “Other approved means” remains as an option to provide support for cables. Support and Securement need to be listed to avoid damage to Type AC cable from inadequate and untested supporting and securement methods. For example, the use of a bent nail is not an adequate method of supporting or securing the cable. Using listed support and securement hardware will reduce the risk of damage and undue stress being transferred to electrical connections.
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It is interesting that this change was accepted by CMP 6, but the same was proposed for raceways and those were rejected by CMP 8.
 
don_resqcapt19 said:
It was submitted by UL and the following was the substantiation:


It is interesting that this change was accepted by CMP 6, but the same was proposed for raceways and those were rejected by CMP 8.
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TLDR: “We’re not solving any existing safety issue. Advancements in tool technology means we can require its use.”
 
hbiss said:
Just to show the thinking that went into this, you would think that they would require insulated staples for NM!

-Hal
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334.30 is amended by my state to require the use of insulated staples when securing cable sizes smaller than three 8 awg conductors .so if you use staples on 8-2 nm and smaller they need to be insulated , 8-3 nm cable and larger it’s your choice not required , as far as I know its been like that for quite a while
 
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