soldering wire connections 110.14 B

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I don't know why anyone would do this now a days but thats the interesting thing about being an inspector.I inspected a house today that someone is wiring the old school way.He twisted the wires together and then soldered and taped them.The grounds he used wire nuts on.It looks really nice and it is a good electrical connection but I said it is not in accordance with the NEC.Then I reread 110.14B and now I am not so sure.I also called two inspectors and one said it is ok and the other said not in my jurisdiction.So does mechanically secure mean that it has to have a splicing device.The first sentence says OR
Conductors shall be spliced or joined with splicing devices identified for the use OR by brazing,welding,or soldering with a fusible metal alloy.Soldered splices shall first be spliced or joined so as to be MECHANICALLY and electrically secure without solder and then soldered.
City of Gretna Electrical Inspector

[ October 11, 2005, 05:11 PM: Message edited by: bassphisher ]
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Re: soldering wire connections 110.14 B

The section you quoted is very clear. You can solder it but only AFTER you have made it mechanically and electrically connected. The reason for this is that solder is not an especially good conductor and will generate substantial heat if current passes through the solder rather then directly from wire to wire.

personally I think a good argument could be made that a granny knot would be adequate for the mechanical and electrical connection made prior to soldering (at least on stranded wire). I don't think it would have to be a crimped on connector.

[ October 11, 2005, 05:23 PM: Message edited by: petersonra ]
 

charlie b

Moderator
Staff member
Location
Seattle, WA
Occupation
Electrical Engineer
Re: soldering wire connections 110.14 B

I don't see an issue with twisting and soldering. But there are good and bad ways of performing the soldering. It may look like a good connection, but I don't know an easy way to test it in-place for mechanical strength or for electrical conductivity.

I might be more concerned about the taping. I do not know how many wraps of what grade of black "electrical tape" is needed to achieve an acceptable degree of insulation for a 120 volt system. Also, what holds the tape in place as time goes by, and as the joint gets "just a little warm" from normal everyday current.

I don't think you can fail the installation on the basis of 110.14(B). But you might be able to suggest to the installer that there are better, quicker, and cheaper ways of doing this task.
 

peter d

Senior Member
Location
New England
Re: soldering wire connections 110.14 B

I used to have a really hard time believing that soldering was still permitted by the NEC. I fought it tooth and nail, and read into the code what wasn't there. The good members of this forum set me straight and showed me the error of my ways. :D
 

hardworkingstiff

Senior Member
Location
Wilmington, NC
Re: soldering wire connections 110.14 B

Originally posted by petersonra:
The reason for this is that solder is not an especially good conductor and will generate substantial heat if current passes through the solder rather then directly from wire to wire.

Rut roh.

Recently (like 2 weeks ago) I was hooking up some #8 type W cable to a neutral bar and ground bar and I soldered the wire (like tinning) prior to inserting it and running the screw down on it. Normally I would use a compression pin terminal for this connection, but they don't make them this small (at least according to my supplier). The reason for the pin terminal is to keep from damaging the wire with the screw (the strands on type W are more susceptible to damage than #12 or #14 stranded I think).

Anyway, do you think I need to go back and cut that off and do something different?

I didn't do it on the breaker because it is a Square D breaker and they don't compress the wire with a screw.

Thanks
 

iwire

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Staff member
Location
Massachusetts
Re: soldering wire connections 110.14 B

Solder has worked successfully for countless years for power wiring.

Prior to items like split bolts solder was even used on large feeders. I have seen 500 Kcmill soldered after the stands where interlaced.

I have removed some that date back to cloth covered and black conduit, they looked perfect. :)
 

charlie

Senior Member
Location
Indianapolis
Re: soldering wire connections 110.14 B

If you are going to solder a bunch of connections, do it the old way properly. Use a ladle with molten solder to solder with. Twist the wires together and orient them downward, flux the joint, bring the ladle up to the joint and hold it for a little while to heat up the wires, then lower the ladle slowly so that a small drop of solder forms on the end (that keeps the end of the wire from poking through the tape). You may now use some self adhering rubber tape and cover it with friction tape (OK, you are permitted to use the new rubber boots that you use with compression connectors).

After getting the hang of doing the connections this way, you will find it as fast as twist on connectors. I would tell you about the pain of working on this type of connection but most of you already know what a pain in the *** it is. :D
 

don_resqcapt19

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Staff member
Location
Illinois
Occupation
retired electrician
Re: soldering wire connections 110.14 B

Bob,
The reason for this is that solder is not an especially good conductor and will generate substantial heat if current passes through the solder rather then directly from wire to wire.
Actually there will be no copper to copper connection in a soldered joint. The wicking effect will completely coat all of the copper.
Don
 
Re: soldering wire connections 110.14 B

I have seen a lot of twisted and soldered solid # 12 with cloth tape at resort cabins in this area. Never seen one fail, but they are a pain. Stranded is another story. I'm not confident of the mechanical reliability of twisting. Maybe where there is no movement or vibration, definitely not a industrial application.
I have seen some guys even older than me that use soldering or tinning the ends of stranded together where connections get made and removed frequently, like when the company is toooo cheap to install reversing starters and electricians swap T-leads in Starter buckets to clear plugs.
Johnny
 

dereckbc

Moderator
Staff member
Location
Plano, TX
Re: soldering wire connections 110.14 B

Originally posted by petersonra:
solder is not an especially good conductor and will generate substantial heat if current passes through the solder
Depends on what kind of solder you are talking about. For example silver solder is a better conductor than copper.
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Re: soldering wire connections 110.14 B

I think twisting the wires is considered a mechanical connection. I don't see a problem with this as long as there is on solder on the grounds.

Steve
 

busman

Senior Member
Location
Northern Virginia
Occupation
Master Electrician / Electrical Engineer
Re: soldering wire connections 110.14 B

Steve,

Check 250-113 ('96 code, sorry) - "Connection devices or fittings that depend solely on solder shall not be used."

I don't think solder can be used to connect equipment grounds.

Mark

[ October 12, 2005, 09:21 AM: Message edited by: busman ]
 
Re: soldering wire connections 110.14 B

Here is a little more explanation.
1)This is a house and not an industrial application.
2)This is solid wire that this was done with.
I will try to explain the best that I can on how it was done.Rember that this is romex and the grounding conductor is twisted and a wire nut is installed.Also this was done with a torch and not a ladle.About 12" of free conductor is at each box.About 6" back 1" of insulation is removed,The long conductor is not cut.The conductors that are to be spliced to this long wire are cut about 6" and are stripped so that now the ends of these wires line up with the piece of insulation that was removed on the long wire which was not cut.So now you have these 6" conductors twisted on to the 12" wire.Then soldered and insulated with black tape.I hope that this makes sense.
My problem is if there is a fault the solder will melt and the magnetic field that is created is soo strong that it could loosen the twists which could create arcing problems down the road.I can not see this being faster or cheaper.And will be interested to ask the electrician why he is still using this old practice.
Would the rest of the inspectors out there approve this or not?
Thanks

[ October 12, 2005, 09:49 AM: Message edited by: bassphisher ]
 

charlie

Senior Member
Location
Indianapolis
Re: soldering wire connections 110.14 B

Twisting does make the joint mechanically secure and soldering makes it electrically conductive. I do not see a problem with that part but I wonder about the way it is taped. That part and the workmanship would be a judgement call. The reason it is still in the Code is that it is a valid method. If you disagree with that statement, it is time to submit a proposal. :D
 

charlie b

Moderator
Staff member
Location
Seattle, WA
Occupation
Electrical Engineer
Re: soldering wire connections 110.14 B

Originally posted by bassphisher: My problem is if there is a fault the solder will melt and the magnetic field that is created is so strong that it could loosen the twists which could create arcing problems down the road.
The wire insulation systems used in such applications are rated for temperatures up to 90C. The eutectic temperature for 60/40 solder is over 180C. So if the fault is strong enough to melt the solder, without first tripping the breaker, then the entire insulation system will also have been destroyed, and the subsequent fire will probably destroy the evidence. ;)

I don't think there is reason for concern. That is, no reason for concern except, as I said before, the quality of the taping job.
 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Re: soldering wire connections 110.14 B

Sorry busman, I meant I think it is OK as long as there is not any solder on the ground wires.

My guess at why solder isn't allowed on the ground wires: a large fault current could melt the solder and open the ground wire.

Steve
 

charlie b

Moderator
Staff member
Location
Seattle, WA
Occupation
Electrical Engineer
Re: soldering wire connections 110.14 B

Originally posted by steve66: My guess at why solder isn't allowed on the ground wires: a large fault current could melt the solder and open the ground wire.
My guess would be a lack of confidence on the part of the code writers in the ability of the average electrician to make an effective solder joint each and every time. I intend no disrespect to members of the profession. But how many of you were given proper training on soldering techniques? My oldest brother (an electronics tech) taught me how to solder in my high school years. I still know enough to know that it is relatively easy to get a joint that looks good but that is not an effective electrical connection. Again, my guess is that the importance of the equipment grounding path is too high to risk a poor connection.

As to a fault melting the solder, I think that would take too much time. The breaker would trip long before the solder would heat up to the melting point. We are talking about fractions of a second here.
 
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