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Safety of twist on wire connectors aka "wire nuts"

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Joseito

Member
Location
Illinois
Hello everyone, I've always been curious about whether wire nuts are insulated in order to comply with the OSHA splice requirement 1910.303(c)(3)(i) that "All splices and joints and the free ends of conductors shall be covered with an insulation equivalent to that of the conductors or with an insulating device identified for the purpose." Are wire nuts acceptable as insulation on a splice? I know it may be unlikely but if someone touches the splice with a wire nut, technically, you can still see copper inside the wire nut (exposed wires). I know tape (usually, regular electricians tape, which 99% of the time is not rated as insulation) is used to secure the splice so the wire nut doesn't fall off, but is that acceptable as insulation replacement?

Thanks in advance for your insight.
 
R

retirede

Senior Member
Location
Illinois
Wire nuts have a voltage rating as part of their listing. As long as you select the correct product, you’re fine.

To tape or not to tape is like discussing politics or religion. I wouldn’t even consider it in the discussion.
 
H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Joseito said:
Hello everyone, I've always been curious about whether wire nuts are insulated in order to comply with the OSHA splice requirement 1910.303(c)(3)(i) that "All splices and joints and the free ends of conductors shall be covered with an insulation equivalent to that of the conductors or with an insulating device identified for the purpose." Are wire nuts acceptable as insulation on a splice? I know it may be unlikely but if someone touches the splice with a wire nut, technically, you can still see copper inside the wire nut (exposed wires). I know tape (usually, regular electricians tape, which 99% of the time is not rated as insulation) is used to secure the splice so the wire nut doesn't fall off, but is that acceptable as insulation replacement?

Thanks in advance for your insight.
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If the wire nut falls off, it was not properly installed, or incorrect size was used. If it is stripped to the length specified by the manufacturer, bare conductor would be impossible to touch without aid of tools. If I remember correctly, scotch 33 is rated for 600 volts with two wraps, but cannot be used alone, as a mechanical connection, along with same thickness of the existing insulation is required. Hence rubber or friction tape underneath.
 
B

BillyMac59

Senior Member
Location
Wasaga Beach, Ontario
Occupation
Industrial Electrician
Not sure where your question is coming from. Are wire nuts acceptable? Do you think they would be used/sold if they were not? As to seeing exposed conductor - well of course you can, even when installed properly. You do realize that if you are at the point of having an "in use" wirenut in your hands, you should have leathers on or the circuit confirmed electrically dead. No exposed conductor should protrude beyond the "umbrella" of the wire nut. If it does, it points to a poor termination and/or an undersized wirenut. (All wirenuts I've encountered over the last 30+ years have both a voltage rating and a size/# of conductors rating.)
 
tom baker

tom baker

First Chief Moderator & NEC Expert
Staff member
Location
Bremerton, Washington
Occupation
Master Electrician
Perhaps the taping of wire connectors is a left over from when setscrew or solder connections were used with rubber tape. Its like ground rods at light poles, we just keep doing it as thats the way we were taught
 
R

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
Joseito said:
Hello everyone, I've always been curious about whether wire nuts are insulated in order to comply with the OSHA splice requirement 1910.303(c)(3)(i) that "All splices and joints and the free ends of conductors shall be covered with an insulation equivalent to that of the conductors or with an insulating device identified for the purpose." Are wire nuts acceptable as insulation on a splice? I know it may be unlikely but if someone touches the splice with a wire nut, technically, you can still see copper inside the wire nut (exposed wires). I know tape (usually, regular electricians tape, which 99% of the time is not rated as insulation) is used to secure the splice so the wire nut doesn't fall off, but is that acceptable as insulation replacement?

Thanks in advance for your insight.
Click to expand...
Thanks for this interesting reference.

This question was discussed here on Dec 11, 2021.

It would appear the answer is NO.

Most twist on wirenuts are neither UL tested, nor rated over 300-600 Volts, depending on package instruction sheet.

Lug kits, such as Alumicon & Lever Locks have much more robust testing & listing data.
 
H

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
ramsy said:
Thanks for this interesting reference.

This question was discussed here on Dec 11, 2021.

It would appear the answer is NO.

Most twist on wirenuts are neither UL tested, nor rated over 300-600 Volts, depending on package instruction sheet.

Lug kits, such as Alumicon & Lever Locks have much more robust testing & listing data.
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Ideal seems to disagree with you, they are UL listed, and have products for up to 1000 volts.
 
R

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
S

SSDriver

Senior Member
Location
California
Occupation
Electrician
ramsy said:
Wow, never noticed any wirenuts in store shelves with a 1000 volt rating. Instructions always say 300-600 max.

Are these actually in stock on a store shelf, or special internet order only?
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My SH stocks them I'm sure they wanted the 1000v rating so t hey could be used for solar.
 
B

billk554

Member
interesting thread. on the wire nut box it recommends that you install the wire nut and bee sure there are at least two twists in the cable being spliced. i will use 33+ to hold the twists together but not for insulation.
 
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
ramsy said:
Most twist on wirenuts are neither UL tested, nor rated over 300-600 Volts, depending on package instruction sheet.
Click to expand...
Have never seen a wirenut, even the cheap junk ones provided with luminaires, that did not have a listing agency mark on them.
 
Dsg319

Dsg319

Senior Member
Location
West Virginia
Occupation
Wv Master “lectrician”
Joseito said:
Hello everyone, I've always been curious about whether wire nuts are insulated in order to comply with the OSHA splice requirement 1910.303(c)(3)(i) that "All splices and joints and the free ends of conductors shall be covered with an insulation equivalent to that of the conductors or with an insulating device identified for the purpose." Are wire nuts acceptable as insulation on a splice? I know it may be unlikely but if someone touches the splice with a wire nut, technically, you can still see copper inside the wire nut (exposed wires). I know tape (usually, regular electricians tape, which 99% of the time is not rated as insulation) is used to secure the splice so the wire nut doesn't fall off, but is that acceptable as insulation replacement?

Thanks in advance for your insight.
Click to expand...
If installed correctly you shouldn’t see copper unless the wire nut is upside down. And even than would have to really try hard to receive a shock.

Again… that is if installed correctly.
 
rambojoe

rambojoe

Senior Member
Location
phoenix az
Occupation
Wireman
I always wanted to start a thread on scary a$% illegal "stuff" that can be done safely... and work forever :) but i'd be shunned and kicked out.. :(
A better question is what does it take to screw up something as simple as a wire nut?!
 
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