Thread: Butt splice connectors

This is the first time I have seen these used in home wiring. I looked them up on the web and are rated at 600 volts building wiring. I know how unreliable these connectors are in 12 volt auto wiring so now wonder if they are allowed in building wiring?

Not sure they are listed for solid wire & there is high likelihood they are automotive connectors,so not listed by any NRTL, just my opinion but just do not like them for that use as shown in the photo.

Even if there are B connectors rated for this use, these look like common automotive 18-22awg connectors.

Originally Posted by Lon Henderson

Even if there are B connectors rated for this use, these look like common automotive 18-22awg connectors.

They make them for larger gauge wire as well. but I am not sure either if they are properly rated or approved

Originally Posted by Vern Heiler

This is the first time I have seen these used in home wiring. I looked them up on the web and are rated at 600 volts building wiring. I know how unreliable these connectors are in 12 volt auto wiring so now wonder if they are allowed in building wiring?

Hi Vern:
Sometimes the way I look at things is just the fact I've never seen them used in this manner. A wire nut holds two conductors in contact with each other very tight when tightening the nut. This type of connector does not allow the two conductors to be in contact with each other and I would be concerned with corosion, resistance, and ampacity of this type of connector over time. Some times the wires can be pulled apart with little effort unlike a wire nut. Not exceptable.

Originally Posted by Mike Borchardt

Hi Vern:
Sometimes the way I look at things is just the fact I've never seen them used in this manner. A wire nut holds two conductors in contact with each other very tight when tightening the nut. This type of connector does not allow the two conductors to be in contact with each other and I would be concerned with corosion, resistance, and ampacity of this type of connector over time. Some times the wires can be pulled apart with little effort unlike a wire nut. Not exceptable.

The real Question is have they been approved for this use ? and they may be but were they assembled correctly or was the right tool used . I say this because so often these are used with the wrong tools and the wrong assembly procedure leading to the failure you describe Mike

The blue ones are rated for 14-16 gauge wire, or 15-amp; at least one manufacturer makes a yellow version for #12 wire. The connector shouldn't fit on a larger wire than intended, so if these are on conductors for 15 amp circuits they MAY be ok. One manufacturer is Gardner Bender but I can't find info on approvals and installation requirements. All products of this nature require the use of approved crimping tools and proper pressure, etc. The approvals are only as good as how well the instructions are followed, including proper type of wire (solid/stranded, copper/aluminum), how the wire is cut/stripped, the crimping tool, and required strain relief or secondary protection.

David

Originally Posted by Vern Heiler

This is the first time I have seen these used in home wiring. I looked them up on the web and are rated at 600 volts building wiring. I know how unreliable these connectors are in 12 volt auto wiring so now wonder if they are allowed in building wiring?

Originally Posted by Dwight Doane

The real Question is have they been approved for this use ? and they may be but were they assembled correctly or was the right tool used . I say this because so often these are used with the wrong tools and the wrong assembly procedure leading to the failure you describe Mike

NEC does not list everything NOT approved. And understandably so. Lets assume for the sake of argument they are approved. Without knowing the requirements for installing them including the proper crimping tool, and not knowing if these were sized correctly for the wire size and type (solid or stranded), I could not approve this based on the unknowns. On the other hand if the person who installed them could show me these are approved for this application and were installed per mfg requirements / specifications then I would have no prolem. I totally agree with you on correct tools and correct assembly. Nice post. Thanks

The use of inline or butt splices in confined spaces such as wiremold or plug mold applications is invaluable. They simply take up less room and fit in where wire nuts do not. As far as them being unreliable, that is entirely a matter of improper installation.

Originally Posted by Mike Borchardt

NEC does not list everything NOT approved. And understandably so. Lets assume for the sake of argument they are approved. Without knowing the requirements for installing them including the proper crimping tool, and not knowing if these were sized correctly for the wire size and type (solid or stranded), I could not approve this based on the unknowns. On the other hand if the person who installed them could show me these are approved for this application and were installed per mfg requirements / specifications then I would have no prolem. I totally agree with you on correct tools and correct assembly. Nice post. Thanks

Those are used many time in electrical work -- especially maintenance. They are every bit as reliable as wirenuts or soldering and taping. You say you would not approve based on not knowing if they were properly crimped or if the proper crimper was used. Do you also question whether wirenuts are properly torqued or the wires in the wirenut properly twisted before the wirenut was twisted onto the splice? Are you going to pay the electrician a service fee to prove to you he made up every connection to your standards?

Turning down something just because you have no understanding of the way materials are assembled is one reason which makes this profession be viewed by craftsmen as charletons.

Originally Posted by Mike Brown

Those are used many time in electrical work -- especially maintenance. They are every bit as reliable as wirenuts or soldering and taping. You say you would not approve based on not knowing if they were properly crimped or if the proper crimper was used. Do you also question whether wirenuts are properly torqued or the wires in the wirenut properly twisted before the wirenut was twisted onto the splice? Are you going to pay the electrician a service fee to prove to you he made up every connection to your standards?

Turning down something just because you have no understanding of the way materials are assembled is one reason which makes this profession be viewed by craftsmen as charletons.

What is the proper torque on a wire nut? Is it measured in inch pounds? Give me a number. Wires properly twisted? How many twists do wires get? Twisting wires together is not required when using wire nuts. Are these But Connectors properly crimped? Don't know.

Originally Posted by Mike Brown

Those are used many time in electrical work -- especially maintenance. They are every bit as reliable as wirenuts or soldering and taping. You say you would not approve based on not knowing if they were properly crimped or if the proper crimper was used. Do you also question whether wirenuts are properly torqued or the wires in the wirenut properly twisted before the wirenut was twisted onto the splice? Are you going to pay the electrician a service fee to prove to you he made up every connection to your standards?

Turning down something just because you have no understanding of the way materials are assembled is one reason which makes this profession be viewed by craftsmen as charletons.

Bringing to light the importance of the assembly and the installation process used with high voltage electrical inline connectors to the client is very important. I believe the gentlemen who have posted here have some experience with crimped connectors. The first hand experience may include automotive/hobby/home projects. Those who have used these crimp/inline connecters know the assembly process is most important. The experienced home inspector is not going to stress, pull on/bend, these inline connections when located to verify they are intact and secured. After a few heavy circuit service use periods the wires/connectors will heat up and expand/contract the assembly. Making them loose and vulnerable to additional heat/aching or disconnection. A wire nut assembly will allow more surface contact, compression of the bare wires vs inline connectors that pinch/crush into the wire and sometimes bite through the wire.
There are 2 types of wire nuts also. Those that are threaded plastic that do not allow compression but screw on and bite into the wires and threaded plastic/metal type that also bite into and thread/expand around the wires securing them in place. Different colors for the size and numbers of wires to be inserted and secured. Use the wrong wire nut and you have the same problems as inline connectors.
I believe if we had more craftsmen building and repairing our homes we wouldn't be thinking the opposite of who is a (correct spelling used here) charlatan.

Grainger sells 3M butt splices in sizes from 4 AWG through 22 AWG:
WP5076123 Vinyl Butt Splice Connector - Grainger Industrial Supply

UL Listed, CSA Certified, RoHS 2011/65/EU
Product Catalog*3M? Butt Connectors*: Electrical Commercial and Industrial: 3M US

Originally Posted by Mike Borchardt

What is the proper torque on a wire nut? Is it measured in inch pounds? Give me a number. Wires properly twisted? How many twists do wires get? Twisting wires together is not required when using wire nuts. Are these But Connectors properly crimped? Don't know.

Pre twisting wires in a wirenut may not be required, but the NEC for many cycles has required that the connection be made mechanically sound before insulation. This harkens back to the time when wires were twisted, soldered and then taped, and is every bit as important when using wirenuts. It may be legal or even to mfg specs to not pre twist, but a pre twisted connection will be the most mechanically and electrically sound connection - almost as good a properly crimped connection.

The other responder who was concerned about coefficient of expansion -- the crimps have the same coefficient since they are alloys built to the specs of copper wiring. That kind of crimp is not rated for aluminum -- you must get aluminum crimps (with aluminum oxide or other paste inside) to but-splice aluminum (Awg 6 and larger) since aluminum has a different coefficient of expansion. Also the oxides of uncoated aluminum play havoc with connection due to higher resistance which increases thermal expansion which over several heat cycles deteriorates the connection.

What the OP did not seem to know is these crimps were first used in 120+ volt AC wiring long before they were used in 12 volt DC wiring.

Crimped connectors should never be used on solid wires. The wire will expand with temperature forcing the crimped terminal open. When the conductor cools, the connector will be loose. On stranded wires, the expanding copper will mostly fill the voids between the strands and not put enough force on the connecter to deform it. This is not a written rule, but I can tell you from installing literally thousands of terminals on machinery over the years, the ones on solid wires will always come loose.
Also, we always pre twist the wires before installing wire nuts on four or more wires, to be sure all the conductors are still in the proper place and one hasn't slipped back or forwards. If one has slipped back, you have to untwist and move it forward. If it slips forward you can just cut the end of the bunch off so it is even and the wire nut doesn't bottom out before tightening up on all the conductors.

Originally Posted by Scott Cook

Crimped connectors should never be used on solid wires. The wire will expand with temperature forcing the crimped terminal open. When the conductor cools, the connector will be loose. On stranded wires, the expanding copper will mostly fill the voids between the strands and not put enough force on the connecter to deform it. This is not a written rule, but I can tell you from installing literally thousands of terminals on machinery over the years, the ones on solid wires will always come loose.
Also, we always pre twist the wires before installing wire nuts on four or more wires, to be sure all the conductors are still in the proper place and one hasn't slipped back or forwards. If one has slipped back, you have to untwist and move it forward. If it slips forward you can just cut the end of the bunch off so it is even and the wire nut doesn't bottom out before tightening up on all the conductors.

Thank you Scott.
I agree 100% with what you said. Twisting severial wires together keeps them aligned (period) Wire nuts will maintain the tensile strenght on the wires. Crimped connectors on solid wire will not. Using the wrong crimping device can damage the connector and wire which is hidden from view by the plastic case. I will not approve this type of connection when wire nuts are proven to be a proper and reliable method.

Originally Posted by Vern Heiler

This is the first time I have seen these used in home wiring. I looked them up on the web and are rated at 600 volts building wiring. I know how unreliable these connectors are in 12 volt auto wiring so now wonder if they are allowed in building wiring?

Those are automotive and marine butt wire connectors . I have used them for my boat and trucks and cars for 30 plus years.
NEC Terminal conductor material. In 404.14(C) and 406.2(C), the Code requires you to use terminals and splicing devices identified for use with the conductor material.

Tightening torques. Terminals must ensure good connections "without damaging the conductors.'

Those crimp connections are damaging to the conductor. That is why they are used for 12 volt.

Originally Posted by Mike Borchardt

NEC does not list everything NOT approved. And understandably so. Lets assume for the sake of argument they are approved. Without knowing the requirements for installing them including the proper crimping tool, and not knowing if these were sized correctly for the wire size and type (solid or stranded), I could not approve this based on the unknowns. On the other hand if the person who installed them could show me these are approved for this application and were installed per mfg requirements / specifications then I would have no prolem. I totally agree with you on correct tools and correct assembly. Nice post. Thanks

Actually, the NEC does not list anything. NRTLs do the testing and listing of products.

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Originally Posted by Mike Borchardt

NEC does not list everything NOT approved. And understandably so. Lets assume for the sake of argument they are approved. Without knowing the requirements for installing them including the proper crimping tool, and not knowing if these were sized correctly for the wire size and type (solid or stranded), I could not approve this based on the unknowns. On the other hand if the person who installed them could show me these are approved for this application and were installed per mfg requirements / specifications then I would have no prolem. I totally agree with you on correct tools and correct assembly. Nice post. Thanks

Actually, the NEC does not list anything. NRTLs do the testing and listing of products.