Solder Dipped Copper

[Donn Lindorfer]

Does anyone know what years solder dipped copper branch wiring was used? I ran across what I originally thought was aluminum branch wiring, but it had some streaks of copper in it. Since the home was built in 1950, and aluminum was not widely used until the mid 60's, I suspect it is not aluminum. I have included a picture, but realize it may be difficult to see.
Thanks!

[Gunnar Alquist]

Donn,

I do not know when "tinned" conductors started or ended, but the early '50s would be about right. At least from what I see in my area. I see it in homes from the '30s to the '50s with knob & tube as well as the older cloth-wrapped NM (ungrounded) cable. Maybe Speedy, JP or HG will chime in with specifics.

[Marcel Cyr]

1965-1973 at which time it was still being used to enable the soldering of connections.
Their rubber coatings used for insulation usually became hard and brittle.

Copper Wire (http://www.hegroup.com.tw/english/ecopper.htm):)

[Gunnar Alquist]

1965-1973 at which time it was still being used to enable the soldering of connections.
Their rubber coatings used for insulation usually became hard and brittle.

Copper Wire (http://www.hegroup.com.tw/english/ecopper.htm):)

Marcel, Are you sure about that? I see it on much older stuff and have not seen it on the '60s or '70s homes at all around here.

[Marcel Cyr]

Gunnar, got it from one of our post at Nachi in 2004 from Gerry Beaumont, and thought my self that it had to be before that. Maybe Jerry Peck knows, he was in that forum thread in 2004.
I remember wiring methods used in the 60's and never seen tinned copper.
If I come across a more accurate year I will post it. :)

[Bill Kriegh]

Tinned copper was used with rubber insulated wire because the copper caused the rubber to deteriorate (more) rapidly with direct contact. They quit making rubber insulated wire in the 50s but people continued to use up old stock for years, some into the earely 60s.

The stuff is always questionable because environmental conditions cause the rubber to become hard and brittle, often to the point of crumbling to dust with slight contact. In almost every case you will find the stuff crumbling when it's in a box above a light fixture because people used too large a wattage lamp.

As to solderability, the rubber reacted with the tinned wire to some extent so the use of flux is pretty much mandated for a good solder joint, as it would be with bare copper. This wouldn't have been so much of an issue when the wire was new.

[Marcel Cyr]

Thanks Bill, and any idea of History link on this stuff?:)

[Marcel Cyr]

Found this article that may help us in the time frame of tinned copper.
Seems to bring us back in the 60's.

Wire and Cable Facts

There are currently thousands of configurations of wire and cable in use today. All of which are specifically designed to achieve a certain purpose. Dockyard Electrics specializes in cable and wire specially suited for the Marine industry as determined by The United States Coast Guard, American Boat and Yacht Council (ABYC) and Underwriters Laboratories (UL) safety, suitability to application as well as economics were considered in determining a range of materials to be used. The focus of Marine wire specifications concerns electrical or power wiring as opposed to electronic, signal or data conducting wire.
There are 3 primary considerations to be evaluated when choosing wire for marine applications, assuming copper as the conductor material:
· Conductor stranding
· Conductor Coating
· Conductor insulation
Conductor Stranding

Stranding is vital in the Marine industry. All agencies will require that marine wire be at least type 11 stranding. The primary reasoning for stranded over solid wire is its flexibility. The benefits of flexible stranding are:
· Usable life of cable: Stranded wire withstands more vibration and flexing before fracture.
· Damage: Nicks or cuts on a strand are less likely to become a conductor fracture.
· Installation: A highly stranded cable is more flexible and easier to install.
In considering stranding, a good rule of thumb is the more strands in a cable, the easier the installation and the longer the life span of the cable.
Conductor Coating

Although there are several coating materials used in wire today, the most common is tinned plating. Coating copper wire began over 40 years ago for the primary purpose of speeding and improving the quality of soldered applications. Bare copper oxidizes to form a copper oxide film. Copper oxide film is a poor conductor of electricity. To effectively solder a copper conductor the oxidation must be removed. Tin oxidizes much more slowly than bare copper, it is also of relatively low cost making it the dominant coating material for general purpose applications. Tin coating helps to make a tin-solder connection sound. The corrosion resistance of tinned copper has an added benefit in Marine applications. Harsh, caustic environments that marine vessels can be subject to will quickly undermine a Boat’s electrical system causing loss of conductivity and key component failure. Tin plating extends a wire’s life span considerably. Dockyard Electrics highly recommends the use of tinned copper in most applications.

[Jerry Peck]

As Bill said, the copper was tinned to reduce the deterioration effect on the rubber insulation from the copper conductors within.

During WWII and afterward with the development of thermoplastics and thermoplastic insulation, rubber insulated wire began to disappear in the 1950s.

Rubber insulated wire was a big thing in the 1920s, 1930s and 1940s, even somewhat into the 1950s.

Thermoplastic insulated wire began in the 1940s, improved such that by the early 1950s it was the prevalent type, and by 1960 had pretty much completely replaced rubber insulated wiring. It basically took less than 10 years for thermoplastic insulated wiring to replacing rubber insulated wiring once the manufacturing processes were worked out. In the overall timing of things, it happened over a very short time period.

Thus, when you see tinned copper you are *most likely* looking at rubber insulated conductors ... which are *most likely* in need or replacing as the rubber has all dried out, becoming brittle, cracking, and losing its dielectric properties. If you run across tinned copper, look at the insulation - 99.99% chance it is rubber, and 99.99% chance it needs to be replaced.

[Ken Rowe]

Donn,

That's tin coated copper. Very common in cloth wrapped wires in the 50's. In fact, I've seen tin coated NM Romex style wiring in houses built in the 80's.

You typically will only see aluminum branch wiring in houses from the early 60's to about '74. Keep on the lookout for it in houses built up to about 1979 as some electricians found they could get away with using up their excess aluminum wiring in one or two circuits of the homes. Also, keep an eye out for remodeling that may have been done in those years as aluminum may have been used. Always look at the cut ends of the wiring at the buss bars to verify aluminum or tinned copper.