Personal Experience With Listed Concealed NM Splicing Devices?

[TRWham]

Does anyone here have any personal experience using the NSI Industries NMS-2 or similar devices to extend existing concealed NM cables without a junction box? They are UL listed and claim to be compliant with 334.40(B) but we are slightly skeptical. I really don't see an issue if they are properly installed, but have never used these and don't know if there is much experience with them in the field.

 

[rlitman]

I've used two. They seemed ok but are very specific to the cable you're using (they're not a universal fit and won't work with UF for example).

edit: be very careful with the details in the instructions. For example, they may work with nm-b, but will not work with nm. A little detail like that is VERY important with these sort of devices.

 

[Codyboy]

Looks cheap.

 

[njride]

I think they **** and are janky but I've use them as a form of cya, maybe they've gotten better lately. I could do a better job with some wire nuts, staples and tape so someone can't blindly pull the splice apart in the future when it's concealed. I avoid any concealed splices, usually if you think a little bit it's not too hard to pull it up or down to an attic or crawlspace and splice in an accessible box there, or just cut in a box with a blank cover behind a painting or dresser, or instead of a blank add another receptacle.

 

[rlitman]

... I could do a better job with some wire nuts, staples and tape so someone can't blindly pull the splice apart in the future when it's concealed...

I've seen several types. The type I used had a metal E shaped backer that the wire snakes through. There's absolutely no way you're pulling it apart. This example picture from the internet shows a splice in the bottom, and a tap connection on the top.


I don't think I'd be comfortable installing one without the metal part. These are not all created equal.

 

[mike93lx]

Considering most receptacles see very low draw, I bet they'll work just fine in nearly all cases.

Especially considering some of the wildly janky **** that people have in their houses.

 

[Codyboy]

I think they **** and are janky but I've use them as a form of cya, maybe they've gotten better lately. I could do a better job with some wire nuts, staples and tape so someone can't blindly pull the splice apart in the future when it's concealed. I avoid any concealed splices, usually if you think a little bit it's not too hard to pull it up or down to an attic or crawlspace and splice in an accessible box there, or just cut in a box with a blank cover behind a painting or dresser, or instead of a blank add another receptacle.

My parents house built in 1973 brand new had splices in the attic. Not sure the even used wire nuts and may have been just twisted together then a lot of electrical tape.
I always wondered why there weren't that many breakers in yhe panel. Lol
It never gave any issues at all.

 

[Chuckster in NJ]

These have been used for years on factory built modular homes……… I have used these several times about 40 years ago without any "known" problems when I was an electrical contractor.
These are "flimsy" and appears to be cheaply made but they are UL Listed so I had no other options available unless I wanted to destroy walls and ceilings.

BTW! When I used them the inspectors would fail me UNTIL they saw the manufactures instructions stating they are UL listed.

 

[larry4406]

Our electricians would use a “Tyco Splice” kit when there was no other choice short of demo. Used on repairs only.

 

[TRWham]

Thanks all for the comments. The Tyco kits, which do seem more robust, apparently have disappeared as I cannot find any available and most everything else I find is for direct burial. I think maybe adding some blocking so we can staple the cable and using the NSI version will work for the few occasions where there is no good alternative. We typically need these for relocation of sconce lights when the fixture is moved farther from the source.

 

[rlitman]

Thanks all for the comments. The Tyco kits, which do seem more robust, apparently have disappeared as I cannot find any available and most everything else I find is for direct burial. I think maybe adding some blocking so we can staple the cable and using the NSI version will work for the few occasions where there is no good alternative. We typically need these for relocation of sconce lights when the fixture is moved farther from the source.

The only place by me that had the Tyco kits when I needed them in 2018 was Lowes, and stock was hit or miss, but perhaps you can order to store.

 

[reader2580]

Tyco Electronics changed to TE Connectivity back in 2011. See https://www.te.com/commerce/DocumentDelivery/DDEController?Action=showdoc&DocId=Data+SheetEPP-33841904pdfEnglishENG_DS_EPP-3384_1904.pdfA22899-000 for a listing of part numbers for the splice kits.

As other posters have stated, the product seems like it is discontinued.

 

[mm08822]

These have been used for years on factory built modular homes……… I have used these several times about 40 years ago without any "known" problems when I was an electrical contractor.
These are "flimsy" and appears to be cheaply made but they are UL Listed so I had no other options available unless I wanted to destroy walls and ceilings.

BTW! When I used them the inspectors would fail me UNTIL they saw the manufactures instructions stating they are UL listed.

Our electricians would use a “Tyco Splice” kit when there was no other choice short of demo. Used on repairs only.

Originally, these were for use in modular homes only, IIRC. Then application scope expanded.

 

[Chuckster in NJ]

Originally, these were for use in modular homes only, IIRC. Then application scope expanded.

TRUE!
IIRC Around 1986-1987 these were starting to be used outside the modular home industry. I think I used these less than 10 times in a few homes that had an interior wall removed……… I made a note of the exact location of these connectors and stuck it above the panel for future reference just in case I needed it.

 

[rlitman]

Oh, I forgot to mention. If you own a Knipex PliersWrench, it's the perfect tool for crunching these closed.

 

[wyliesdiesels]

Ive used them a few times without issue