Maker Pro
Maker Pro

NEC on soldering wiring

  • Thread starter Michael Moroney
  • Start date
M

Michael Moroney

Jan 1, 1970
0
Dumb question:

Does the NEC specifically allow, forbid or is silent on the subject of
soldering home electrical wiring (type NM solid copper) together before
using wire nuts?
 
B

Bob Weiss

Jan 1, 1970
0
Michael said:
Dumb question:

Does the NEC specifically allow, forbid or is silent on the subject of
soldering home electrical wiring (type NM solid copper) together before
using wire nuts?


Not specifically, but 110.3(b) requires you to use the wirenuts in
accordance with the manufacturer's directions. If they don't tell you to
solder the wires first, you would be using the wirenuts in a manner that
they were not tested and listed for. You are then technically in
violation of the NEC.

Bob Weiss N2IXK
 
D

daestrom

Jan 1, 1970
0
Michael Moroney said:
Dumb question:

Does the NEC specifically allow, forbid or is silent on the subject of
soldering home electrical wiring (type NM solid copper) together before
using wire nuts?

Well, as others have shown, there are all sorts of details.

Sometimes solder is okay, but sometimes it can actually make the situation
worse. Solder is generally softer than copper so with mechanical fittings
it 'squeezes' out of the connection and loosens the connection over time.

Best answer is always, use listed devices/components and install in
accordance with the manufacturer's instructions. Generally, that means do
*not* solder wires used in wire-nuts. Over in alt.engineering.electrical
there are also a lot of dicussions about this and the other often-asked
question, "Should you twist the wires together before installing the
wire-nut?"

daestrom
 
D

daestrom

Jan 1, 1970
0
daestrom said:
Well, as others have shown, there are all sorts of details.

Sometimes solder is okay, but sometimes it can actually make the situation
worse. Solder is generally softer than copper so with mechanical fittings
it 'squeezes' out of the connection and loosens the connection over time.

Best answer is always, use listed devices/components and install in
accordance with the manufacturer's instructions. Generally, that means do
*not* solder wires used in wire-nuts. Over in alt.engineering.electrical
there are also a lot of dicussions about this and the other often-asked
question, "Should you twist the wires together before installing the
wire-nut?"

Well that was stupid, this *IS* alt.engineering.electrical. Look in the
archives here and see the various opinions.

daestrom
 
B

Bud--

Jan 1, 1970
0
"110.14 (B)
Soldered splices shall first be spliced or
joined so as to be mechanically and electrically secure without solder
and then be soldered.

"Mechanically and electrically secure" is commonly done by twisting the
wires in a pigtail splice.

I agreee with the intrepretations of Bob and Tom.

bud--
 
Looks like what we used to call a 'telephone splice'. Something the phone
man used, not for 'real electricians' :)

That is a Western Union splice but it was also what an electrician
used for K&T back in the olden days
 
S

Spokesman

Jan 1, 1970
0
daestrom said:
Looks like what we used to call a 'telephone splice'. Something the phone
man used, not for 'real electricians' :)


You must be too young to know any "real electricians"

This splice was taught in trade school when I was an apprentice. Never used
it
since it was a holdover from knob and tube days.
 
J

John Gilmer

Jan 1, 1970
0
That is a Western Union splice but it was also what an electrician
used for K&T back in the olden days

I recall the name, "WireMan's Splice." But we are all singing from the
same page of music. This particular splice was strong enough to be used to
repair or initially join conductors suspected between to telegraph/telephone
poles. As such is predated electrical power wiring.
 
D

daestrom

Jan 1, 1970
0
Spokesman said:
You must be too young to know any "real electricians"

I wish I was 'young' again. No, but 'real electricians' don't mess around
with wire measured in AWG :)

You can't make a splice like that in the kinds of wire some 'real
electrician's use, the wire doesn't bend that easily :)

daestrom
 
| Michael Moroney wrote:
|> Dumb question:
|>
|> Does the NEC specifically allow, forbid or is silent on the subject of
|> soldering home electrical wiring (type NM solid copper) together before
|> using wire nuts?
|
|
| Not specifically, but 110.3(b) requires you to use the wirenuts in
| accordance with the manufacturer's directions. If they don't tell you to
| solder the wires first, you would be using the wirenuts in a manner that
| they were not tested and listed for. You are then technically in
| violation of the NEC.

I disagree. If the directions tell you to use solder, then you must do so.
If the directions tell you not to use solder, then you must not do so.
But if the directions do not say one way or the other, you can make no
assumptions about any requirement. I believe that it is then not specified
one way or the other, and thus either choice complies with the directions,
and thus the standard. Of course it is your responsibility to be sure you
do not overlook any directions.
 
| Tom Horne, Electrician wrote:
|
|> "110.14 (B)
|> Soldered splices shall first be spliced or
|> joined so as to be mechanically and electrically secure without solder
|> and then be soldered.
|
| "Mechanically and electrically secure" is commonly done by twisting the
| wires in a pigtail splice.

Just how much electrical contact exists between two solid copper wires
twisted together? Depending on the compressibility of the copper, it
could be rather small. It certainly is small where one wire contacts
another at an angle. Twisting would have a linear, twisted, line of
content for the length of the twist. But how much length is needed to
provide sufficient contact to avoid hazardous temperature rise? And
how well would it stay this way under the effects of slight corrosion
in the long term?

I've personally see a couple cases where twisted wires under a wire nut
overheated. Fortunately, the damage was limited to the wirenut and
some of the wire insulation.
 
B

Bud--

Jan 1, 1970
0
| Tom Horne, Electrician wrote:
|
|> "110.14 (B)
|> Soldered splices shall first be spliced or
|> joined so as to be mechanically and electrically secure without solder
|> and then be soldered.
|
| "Mechanically and electrically secure" is commonly done by twisting the
| wires in a pigtail splice.

Just how much electrical contact exists between two solid copper wires
twisted together? Depending on the compressibility of the copper, it
could be rather small. It certainly is small where one wire contacts
another at an angle. Twisting would have a linear, twisted, line of
content for the length of the twist. But how much length is needed to
provide sufficient contact to avoid hazardous temperature rise? And
how well would it stay this way under the effects of slight corrosion
in the long term?

But the twisted wire is then soldered. It was a common practice when
splicing in a box before wirenuts. My understanding is the twisted wire
sets were pointed down and then a solder pot was raised under them. I
have seen one of this type of joint fail, and one knob and tube tap fail
where the tap wire was twisted around the running wire. In both cases
the original soldered joint was bad ("cold" solder connection).

bud--
 
| [email protected] wrote:
|
|>
|> | Tom Horne, Electrician wrote:
|> |
|> |> "110.14 (B)
|> |> Soldered splices shall first be spliced or
|> |> joined so as to be mechanically and electrically secure without solder
|> |> and then be soldered.
|> |
|> | "Mechanically and electrically secure" is commonly done by twisting the
|> | wires in a pigtail splice.
|>
|> Just how much electrical contact exists between two solid copper wires
|> twisted together? Depending on the compressibility of the copper, it
|> could be rather small. It certainly is small where one wire contacts
|> another at an angle. Twisting would have a linear, twisted, line of
|> content for the length of the twist. But how much length is needed to
|> provide sufficient contact to avoid hazardous temperature rise? And
|> how well would it stay this way under the effects of slight corrosion
|> in the long term?
|>
|
| But the twisted wire is then soldered. It was a common practice when
| splicing in a box before wirenuts. My understanding is the twisted wire
| sets were pointed down and then a solder pot was raised under them. I
| have seen one of this type of joint fail, and one knob and tube tap fail
| where the tap wire was twisted around the running wire. In both cases
| the original soldered joint was bad ("cold" solder connection).

That's one of the worst ways to solder it. OTOH, I have in fact tried
to solder large solid gauge copper wire, and it's a bitch. An electric
solder gun is nearly useless. And a torch is very messy.

And still, a solder joint can have bi-metal issues. If only there was
practical way to do small scale tiny CadWelds.
 
J

John Gilmer

Jan 1, 1970
0
I've personally see a couple cases where twisted wires under a wire nut
overheated.

I had a wire nut connect fail OPEN. It was in a house that had been vacant
for about a year. When the power came back on the connection "worked" for
a few months and then one day it was OPEN.
 
D

daestrom

Jan 1, 1970
0
| [email protected] wrote:
|
|> On Sat, 09 Sep 2006 10:48:45 -0500 Bud-- <[email protected]>
wrote:
|>
|> | Tom Horne, Electrician wrote:
|> |
|> |> "110.14 (B)
|> |> Soldered splices shall first be spliced or
|> |> joined so as to be mechanically and electrically secure without
solder
|> |> and then be soldered.
|> |
|> | "Mechanically and electrically secure" is commonly done by twisting
the
|> | wires in a pigtail splice.
|>
|> Just how much electrical contact exists between two solid copper wires
|> twisted together? Depending on the compressibility of the copper, it
|> could be rather small. It certainly is small where one wire contacts
|> another at an angle. Twisting would have a linear, twisted, line of
|> content for the length of the twist. But how much length is needed to
|> provide sufficient contact to avoid hazardous temperature rise? And
|> how well would it stay this way under the effects of slight corrosion
|> in the long term?
|>
|
| But the twisted wire is then soldered. It was a common practice when
| splicing in a box before wirenuts. My understanding is the twisted wire
| sets were pointed down and then a solder pot was raised under them. I
| have seen one of this type of joint fail, and one knob and tube tap fail
| where the tap wire was twisted around the running wire. In both cases
| the original soldered joint was bad ("cold" solder connection).

That's one of the worst ways to solder it. OTOH, I have in fact tried
to solder large solid gauge copper wire, and it's a bitch. An electric
solder gun is nearly useless. And a torch is very messy.

Try resistance soldering tools. A sort of clamp/plier whose each jaw is
insulated from the other. Squeeze the already twisted wires and click the
switch. Several amps flows from one jaw through the work to the other jaw,
heating it up nice and quick. Use them a lot when making all the
connections inside a motor (a lot of different coil groups to make up and
interconnect). Of course, we're soldering 'magnet wire' that is insulated
with enamel and some high-temp stuff. May get too hot and melt simple
plastic insulation.

daestrom
 
| Try resistance soldering tools. A sort of clamp/plier whose each jaw is
| insulated from the other. Squeeze the already twisted wires and click the
| switch. Several amps flows from one jaw through the work to the other jaw,
| heating it up nice and quick. Use them a lot when making all the
| connections inside a motor (a lot of different coil groups to make up and
| interconnect). Of course, we're soldering 'magnet wire' that is insulated
| with enamel and some high-temp stuff. May get too hot and melt simple
| plastic insulation.

An interesting concept. Just how many amps does it take to make a 10 AWG
copper wire heat up to the point it can be soldered? That would be a huge
number, I would think. But perhaps the heat is from the smaller cross
section of the wire to wire contact. If that is so, that would suggest
to me that twisted and capped is actually not good enough.

Just how hot will such a twisted and capped connection get with the 125%
level of current flow? For solid wire? For stranded wire?

I would much rather have some more solid kind of way to connect wires, such
as a terminal block.
 
D

daestrom

Jan 1, 1970
0
On Tue, 26 Sep 2006 20:53:53 GMT daestrom

| Try resistance soldering tools. A sort of clamp/plier whose each jaw is
| insulated from the other. Squeeze the already twisted wires and click
the
| switch. Several amps flows from one jaw through the work to the other
jaw,
| heating it up nice and quick. Use them a lot when making all the
| connections inside a motor (a lot of different coil groups to make up
and
| interconnect). Of course, we're soldering 'magnet wire' that is
insulated
| with enamel and some high-temp stuff. May get too hot and melt simple
| plastic insulation.

An interesting concept. Just how many amps does it take to make a 10 AWG
copper wire heat up to the point it can be soldered? That would be a huge
number, I would think. But perhaps the heat is from the smaller cross
section of the wire to wire contact. If that is so, that would suggest
to me that twisted and capped is actually not good enough.

Never measured the actual amperage in the tool, but yes it is
'considerable'. Think of your typical soldering 'gun' with a tip connected
across the secondary of a significant step-down transformer. Remove the tip
and put some large leads from the gun output to the forceps/pliers and you
have the idea.

Now replace the gun with a small portable welder. Don't actually draw an
arc, but that's the kind of current we're talking, perhaps 50 amps or so
through the twisted joint of two #10 wires. Hot enough to solder in a few
seconds. But yes, the 'jaws' of the tool get hot too, so it may be a lot of
heat is in the small contact surface between tool's jaws and the work.
Just how hot will such a twisted and capped connection get with the 125%
level of current flow? For solid wire? For stranded wire?

I would much rather have some more solid kind of way to connect wires,
such
as a terminal block.

Well, that's your perogative. But the individual coils within most large
motors (up to say about 100 hp) are connected this way. Been done like this
for years. Process is a lineman type of twisted splice, solder, insulate,
tie down, go on to next connection. The 'tie down' is important to prevent
mechanical stress/vibration.

Not that I'm advocating tinning stranded wire under wire-nuts. It's my
understanding that the soft solder alloy will 'creep' with time and loosen.
When all else fails, RTFM, or in this case, "install in accordance with the
manufacturer's directions".

daestrom
 
Top