Electrical Wiring FAQ (Part 2 of 2)
Section - Aluminum wiring
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Electrical Wiring FAQ (Part 2 of 2)
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Section - Aluminum wiring
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During the 1970's, aluminum (instead of copper) wiring became quite popular and was extensively used. Since that time, aluminum wiring has been implicated in a number of house fires, and most jurisdictions no longer permit it in new installations. We recommend, even if you're allowed to, that do not use it for new wiring. But don't panic if your house has aluminum wiring. Aluminum wiring, when properly installed, can be just as safe as copper. Aluminum wiring is, however, very unforgiving of improper installation. We will cover a bit of the theory behind potential problems, and what you can do to make your wiring safe. The main problem with aluminum wiring is a phenomenon known as "cold creep". When aluminum wiring warms up, it expands. When it cools down, it contracts. Unlike copper, when aluminum goes through a number of warm/cool cycles it loses a bit of tightness each time. To make the problem worse, aluminum oxidises, or corrodes when in contact with certain types of metal, so the resistance of the connection goes up. Which causes it to heat up and corrode/ oxidize still more. Eventually the wire may start getting very hot, melt the insulation or fixture it's attached to, and possibly even cause a fire. Since people usually encounter aluminum wiring when they move into a house built during the 70's, we will cover basic points of safe aluminum wiring. We suggest that, if you're considering purchasing a home with aluminum wiring, or have discovered it later, that you hire a licensed electrician or inspector to check over the wiring for the following things: 1) Fixtures (eg: outlets and switches) directly attached to aluminum wiring should be rated for it. The device will be stamped with "Al/Cu" or "CO/ALR". The latter supersedes the former, but both are safe. These fixtures are somewhat more expensive than the ordinary ones. 2) Wires should be properly connected (at least 3/4 way around the screw in a clockwise direction). Connections should be tight. While repeated tightening of the screws can make the problem worse, during the inspection it would pay off to snug up each connection. Note that aluminum wiring is still often used for the main service entrance cable. It should be inspected. 3) "push-in" terminals are an extreme hazard with aluminum wire. Any connections using push-in terminals should be redone with the proper screw connections immediately. 4) There should be no signs of overheating: darkened connections, melted insulation, or "baked" fixtures. Any such damage should be repaired. 5) Connections between aluminum and copper wire need to be handled specially. Current Canadian codes require that the connectors used must be specially marked for connecting aluminum to copper. The NEC requires that the wire be connected together using special crimp devices, with an anti-oxidant grease. The tools and materials for the latter are quite expensive - not practical to do it yourself unless you can rent the tool. [Note that regulations are changing rapidly in this area. Suggest that you discuss any work with an inspector if you're going to do more than one or two connections.] 6) Any non-rated receptacle can be connected to aluminum wiring by means of a short copper "pigtail". See (5) above. 7) Shows reasonable workmanship: neat wiring, properly stripped (not nicked) wire etc. If, when considering purchasing a home, an inspection of the wiring shows no problems or only one or two, we believe that you can consider the wiring safe. If there are signs of problems in many places, we suggest you look elsewhere. If the wrong receptacles are used, you can replace them with the proper type, or use pigtails - having this professionally done can range from $3 to $10 per receptacle/ switch. You can do this yourself too. There's a useful article at [inspect-ny.com]
User Contributions:1 Dev Dec 21, 2011 @ 12:00 am In a fire protection circuit, circuts are shown witha no example 6,8,4etc. what it mean?these circuits are connected between smode detector,junction box etc 2 kevin Dec 24, 2011 @ 12:12 pm My daughter dropped a small necklace behind her dresser. The necklace crossed a plug terminal and shorted the receptacle.
I bought a new receptacle and installed the same. I still have no power I suspect there could be a bigger problem,this is aluminum wiring.
I've killed the breaker and call an electrician but am curious as to what happened.P.s. there is a dimmer switch on the same circuit. 3 dennis Feb 24, 2012 @ 11:11 am Regarding new construction wiring and running 12/2 and 14/3 wire in the same box.
I have multiple switches to lights. Ran 12/2 and 14/3 into switch box and inspector wrote correction needed.
What should I have done instead?
dennis 4 Robert Nov 26, 2012 @ 9:21 pm Does a grounding electrode facilitate the operation of a OCPD, to clear a ground fault ? 5 @dennis Mar 18, 2013 @ 10:10 am Assuming you are installing two switches in a two switch box, you probably should have used 14/2 and 14/3 instead of replacing 14/2 with 12/2. If you are only installing one switch in a one switch box, you should only have one cable in the box. 6 P k Jan 26, 2014 @ 10:10 am I prefer to use nothing smaller than12 awg /the smallest sized wire on a circuit determines the allowable ampacity
Ex: 15 amp-14awg. 12awg-20amp only rule for thumb other factors such as continuous load,heating and others if you do not know the safe NEC rules then please call a qualified journeyman Electrician better be safe
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