residential electrical wiring in older home

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I thought about buying an older home built in the 50's in around Houston, Texas but I was wondering about the electrical wiring.
a) does anyone know if aluminum wiring was used, when this area switched over to copper wiring?
b) briefly what advantages does copper have over aluminum?
c) without pulling off outlet/switch plates, is there an easy way to tell if the house has aluminum or copper wiring? Can aluminum wiring use a breaker box or only fuses?
d) for a 1 story 1500 sq foot home circa 50's, what an electrician might charge to switch wiring?
e) advice buying an older home with respect to electrical wiring?
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On 03/24/2012 05:26 PM, Doug wrote:

I believe it was mostly used in the mid-60s through mid-70s, but I really don't know for sure.

It doesn't cause all the problems with corrosion, poor connections (due to thermal expansion/contraction), and subsequent heat/fire due to the resistance of the poor/corroded connections.

I'm not sure that there is a reliable way to tell without actually seeing the ends of some wires. I would ask if the home moaner would let you remove the cover to the breaker box.

I don't know, I do pretty much all electrical work myself.

Also check for grounding. About the time frame you mention is when grounded Romex was introduced. Older houses may use ungrounded "rag" wiring which while perfectly safe if in good condition will not provide a grounding conductor which you'll really want to have to protect today's electronics (lots of "surge strips" rely on the grounding conductor to provide a path for diverted surge voltage.) I had a house built in '47 or '48 w/o ground. Grandmother's house built in mid-50s had ground, although non-grounding type receps.
Presence of grounding type receps and good test with pocket tester is no assurance of proper wiring. My old house was "faked" with the ground terminal bootlegged to the neutral at the receps, not legal, but it was done - as I discovered to my chagrin when I started replacing old, worn out receps that wouldn't hold a plug anymore. Not an easy fix.
nate
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On 3/24/2012 5:26 PM, Doug wrote:

Not likely that any of the smaller conductors would be aluminum. Possibly the larger conductors like the service entrance, range circuit, central air circuit, or electric dryer circuit, may be aluminum. There is no problem with larger aluminum conductors, only the 12 and 10 gauge, that was used for general lighting and outlets. You should be able to ask the seller, or broker to find out what's in the house. Unless the cable is type AC (BX), there is a possibility that it's non grounding Romex, which can be a pain in certain circumstances, none of which should prevent you from buying the house.
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On 3/24/2012 4:26 PM, Doug wrote:

The Al branch circuit wiring craze was generally in the mid-60s; the chances of it in a 50s house are nil.
Al tends to oxidize and has higher thermal coeff of expansion so tends to loosen connections w/ time more than Cu. The biggest issue is the oxidation layer and contact resistance at connections that acts as a miniature heater and eventually can reach combustion temperatures if gets bad enough.
You'll have a home inspection done, anyway, wiring is just one of the many issues to have verified and discover if there needs to be either work done prior to the sale or discount the offer to cover the cost to yourself after the sale.
--
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On 3/24/2012 6:54 PM, dpb wrote:

Not exactly nil, but pretty close. As with a number of electrical materials, some things were available long before anyone cared to use them. Small gauge aluminum building conductors were around since the 40's, possibly because of the war, but the era of aluminum wiring that strikes fear in homeowners, is primarily from 65' to 73'. Sometimes earlier conductors with tinned copper is mistaken for aluminum.

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On 3/24/2012 6:14 PM, RBM wrote:

A lot of early copper house wiring was tinned because connections were soldered then wrapped with friction tape. I've found this in a lot of older homes during remodels and the insulation appears to be tar impregnated cloth which will often crumble away when disturbed especially if it's been exposed to heat as in light fixtures. I worked for an electrical supplier in the early 1970's during the oil shortage and a copper shortage when many electrical manufacturers switched to aluminum for Romex and they added a lot of fillers to petroleum sourced plastic insulation to keep the electrical industry alive. I was glad I owned a car that had an 1108cc engine during that time. The problem with aluminum house wiring showed up even then because the manufactured housing industry was using a lot of it and when the trailers bounced down the highways for delivery, the aluminum wiring had a tendency to fail because it lacked the ductile properties of copper and could not tolerate mechanical and thermal stress the way copper could. Electricians of the day weren't used to working with small aluminum conductors and the connections would often burn up setting homes, especially mobile homes on fire. Over the years I've found a lot of failed connections in aluminum Romex and had to add the special connectors and copper jumpers in order to replace damaged wiring devices. The special connectors containing antioxidant grease are available at most home improvement stores and you can use them to add copper jumpers to your aluminum house wiring.
TDD
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On 3/25/2012 8:13 AM, The Daring Dufas wrote:

I read tinning was to protect the copper from the rubber insulation (sulfur?). (I don't know.)

Thermal expansion is part of the problem. The "old technology" aluminum wire was too ductile - it would extrude and creep. Probably a larger problem is an insulating aluminum oxide layer that very rapidly forms on any 'clean' aluminum surface. The actual metal-to-metal contact area in a connection may be very small. For large wires, tightening the connection deforms the wire which breaks the oxide layer.

Another post has a link to: http://www.kinginnovation.com/pdfs/ReducingFire070706.pdf which was written by the engineer that supervised extensive testing of aluminum connections for the CPSC. A basic element in connections is abrading the wire to remove the oxide and applying antioxide paste. He does not particularly like the Ideal 65 wirenuts that come with antioxide paste in them. They are, last I heard, the only UL listed wire nuts for aluminum. They are not more effective than some other wirenuts with antioxide paste added, and have some negative features.
http://www.kinginnovation.com/products/electrical-products/alumiconn / may be the best splice for small branch circuit aluminum wires. The screws should dig through any oxide layer, like on larger aluminum wire connections.
--
bud--


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On 3/26/2012 12:41 PM, bud-- wrote:

As usual, the Budman is correct. According to the electrical wiring historian, David E. Shapiro, without the tinning, the rubber coating would have to be scraped off of the copper because of "gluing caused by catalytic action. It certainly didn't hurt in the process of soldering the conductors either.

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On 3/26/2012 1:01 PM, RBM wrote:

That's what I get for listening to Old Sparky and not researching it for myself. He told me that his tools included an old fashioned blow torch and a big honking soldering iron. The first wire nuts he ever saw were ceramic or porcelain. I understand the sulfur because that was the magic ingredient Charles Goodyear discovered was the missing element needed to cause latex to vulcanize into something useful. ^_^
TDD
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On 3/26/2012 2:56 PM, The Daring Dufas wrote:

My dad did electrical work as a kid, then when he got home after ww2, he started his own electrical contracting business. I started working with him in the early 70's. I remember a drawer in the shop's workbench that had a couple of those big honkin soldering irons. I'm sure they got kicked around for years and finally got tossed. I don't remember seeing any kind of lead melting pot, just those massive irons. I never did ask him if or when he used them, but I'll be sure to do so next time I see him.
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On 3/26/2012 3:51 PM, RBM wrote:

I did a bit of searching and found this:
Electricians used blow torches in their work as well. You may have noticed the hook on top of the burner head and the vee groove at the mouth of the burner head. These were used to hold a soldering iron in the flame of the torch whereby the electrician would use the soldering iron to solder wires together. The soldering iron was used by radiomen as well as electricians. The other interesting technique used by electricians is that they would twist the wires together in a junction box, then take a ladle that had a swivel mechanism. The ladle was at the end of a steel handle about 18 inches long. The object of the swivel was so no matter what angle the handle was in, the ladle, which held molten lead, would always be vertical. The electrician would walk through his new construction project, hold this ladle up to his freshly twisted wires, and dip the wires into the lead. This was done so the electrical connections would not work loose.
Zangobob's Blow Torch Heaven
http://www.blotorches.com /
TDD
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On 3/26/2012 7:51 PM, The Daring Dufas wrote:

My understanding is that they use the pot or ladle when they were doing new construction or rural electrification upgrades, and used the irons for "non production" splices. What a PIA. Every day I thank my lucky stars for never having to use a blow torch, massive soldering iron, brace & bit, or knobs & tubes, hell I hated having to use a 3/16" star drill to hand drive rawl plugs. I'm just spoiled
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On 03/26/2012 10:11 PM, RBM wrote:

Brace and bit is still handy when you have just a couple holes to drill and it's quicker than running an extension cord ('cause you're running wire, and the power in the area is cut off.) Yeah, I have one and it has a place in my tool stash.
nate
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On 03/26/2012 10:11 PM, RBM wrote:

[christmas presents]
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For tight spaces I actually prefer my little right angle drill (forget brand; salvaged it from a friend's junk pile and had to clean it up and put a new chuck on it) with a spade bit - will bore nice straight holes in wall studs for an easier pull.
nate
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I still love the look of a well-soldered connection. That baby will outlast the building with no chance of working loose. But, I'll gladly use a soldering gun or electric iron instead of a blowtorch.
Tomsic
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On 3/26/2012 9:11 PM, RBM wrote:

Here are a few examples of the old way, one image has the solder pot on the swivel handle and another image shows the iron on the blow torch itself. ^_^
http://preview.tinyurl.com/c7cghph
http://preview.tinyurl.com/cfkbu6c
TDD
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On 03/24/2012 06:54 PM, dpb wrote:

Not sure how it works in the OP's area, but no home inspector that I've seen is going to remove the cover to the breaker panel and/or a recep cover plate. All they can do is plug in a tester and make sure that all the right lights light up.
nate
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The home inspector I just hired took both covers off and took pretty pictures to go in the scrap book he put together of the house. ;-)
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On 03/24/2012 08:33 PM, snipped-for-privacy@att.bizzzzzzzzzzzz wrote:

Both the inspector that did the inspection before I bought my house and the one that did it for the eventual buyers said that they weren't *allowed* to do so. State law, or just some kind of organization thing? I don't know.
I really wish the first guy would have done so however, I would have negotiated down when I saw that the "updated wiring" was an illegal hack job.
nate
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