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Old 12th October 2013, 09:12 PM   #21
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Holy banana skins Batman! I must say that is some pretty extensive damage.

There are about half a million homes here in Canada with aluminum wiring and lots of fires to go along with it. Back in the 70's they didn't know any better. Branch circuit wiring is of course banned now and I'm guessing it is everywhere for obvious reasons.

I'm glad the electrician told you about the pigtails as rewiring the whole house is a *****. You really shouldn't have to. You can also get new receptacles and switches rated for aluminum but I think pigtails will be cheaper. Ask your electrician.

Go hug your wife and kids, and start counting those blessings.
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Old 12th October 2013, 09:44 PM   #22
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Thank God you and your family are OK. I'm glad you're getting things checked out and upgraded as appropriate. That way you're good to go with the next Pass amp project!
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Old 14th October 2013, 10:05 AM   #23
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You may need to install GFIs/RCCBs.

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Old 15th October 2013, 03:16 AM   #24
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My house is all copper, but in the 36 years I have lived here the same thing has happened to me TWICE.

The first time it was an outdoor outlet and my wife had plugged in about two million Christmas lights overloading the outlet. The circuit breaker never tripped despite 26 amps flowing through a 20 amp GFI breaker. The outlets are all rated for 15 amps and are fed by a 20 amp breaker. This was OK by the code in 1977 and may still be, assuming that you aren't going to draw all the current from a single outlet. I replaced the outlet and the GFI and didn't think much about it.

A few years later my wife turned on the vacuum cleaner, and fireworks erupted from another outlet down the wall in the same room. The outlet fried like yours, and again the breaker never tripped. This time I decided to figure out what was going on. I started ripping out outlets and light switches, and found several more that had shown evidence of overheating. The switches all looked OK, so I decided to replace every outlet in the entire house.

I went over to Home Depot and bought a big box of new outlets. They weren't that expensive, but it was about 15 years ago. This is where I found the real problem. The new outlets, and the old ones, have two methods of attaching the wire. You can strip, the wire, then wrap it around a screw head and tighten the screw, or you can simply strip the wire and stick it in a hole in the back of the outlet. The hole goes into a wedge cut into the copper strip inside the outlet that forms the contact with the plugs that are plugged into the outlet. This creates a point contact with the wire. Over 20 years of heating and cooling cycles created by high current flow, added with life in Florida's high humidity, leads to the green growth and a corroded contact.

So why didn't the outlet with the vacuum cleaner blow? At least when this house was wired (1977) it was common to "daisy chain" the outlets. The hot wire from the breaker panel goes into the first outlet on one screw (or hole) and out to the next outlet on the other screw (or hole). This repeats for the hot lead for ALL outlets on the same branch circuit. This means ALL of the current for one branch flows through the first outlet. Remember the outlets are rated for 15 amps, but the breakers are 20 amps.

Next, read the specs on the breakers, especially the 40 year old ones in this house. A 20 amp breaker can pass 30 amps for 5 minutes before it blows and needs 50 AMPS! to trip instantaneously. This is why 26 amps of Christmas lights can light up for 4 hours a night for several years before frying the outlet.

So, when replacing the outlets, DO NOT stick the wire in the hole. Wrap it around the screw, and tighten it good. It is a good idea to re-tighten them, and all the screws in the breaker panel every few years. This is especially important with aluminum wire.

I have heard about the copper pigtails. This also has problems in humid environments due to the bimetallic contact. Back in the 70's when aluminum wiring was common, you had to get outlets and switches rated for direct use with aluminum wire. I don't know if you can get them any more, but they should be marked AL/CU.

My house is wired with another evil 70's spec that is no longer allowed. This one causes your fancy stereo equipment to spontaneously combust due to being fed 240 volts. Google "shared neutral" for info on this one. Again keep all the screws tight and avoid using the hole to keep the flames away.

Shared neutral:

http://static.schneider-electric.us/...DB0203R902.pdf
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Old 17th October 2013, 03:44 PM   #25
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A big problem is these loop throughs...

Before about 1970 nobody much had homes that used electricity for much more than a vacuum cleaner, toaters and lights, a radio. Then came window airconditioners. Then came electric rotisseries, and the like. More and more stuff to plug in. Color TVs drew a boatload of juice. Same number of outlets.

Modern times, I must have nearly 100 actual outlet sockets in my lab. Wiremold steel wall mounted box conduits (what's it really called?) with a quad ever 2 feet fed off a dedicated 240vac line off a master multi kW iso transformer. And you know what? I am still short outlets. No, I don't turn everything on at once.

About 30-40 around the central gear in the listening room!

But you know what? If I was to wire a new kitchen, I'd want what amounts to the same thing... a quad or more of outlets every few feet!!

If you tell this to a typical electrician they will think you quite mad.

Things have changed. Russellc I'd have fresh copper wire run up to your kitchen with new quad outlets to handle all the high current stuff... same for your stereo of course, and run that off an iso transformer. DEFINITELY for the ELECTRIC DRYER, if you have an electric.

There is goop that is supposed to go on all aluminum connections.
I'd redo each and every connection in the house, clean the aluminum conductors with *scotchbite* pads (DO NOT use abrasive paper or worse steel wool) then apply the proper goo and redo the connections. I can't see the benefit of a copper pigtail, but if that's the solution that has been approved and tested, then use it, but be sure to read up on how it has to be done - any deviation will create problems, big problems.

No point in waking up in a burn ward after being toasted while asleep.

Btw, that would be a cheap $7K to spend if that's all it would take. I'd
not think twice, and I'd redo the entire system so that there were fewer loop throughs where any juice was being drawn.

...my $2.59 (that's 2 cents with inflation)
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Last edited by bear; 17th October 2013 at 03:46 PM. Reason: keep leaving out key words - DOH!
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