A while back,I’ve been given rolls of different color/gauge combination wires.Although they were leftovers,they mostly are of considerable lengths that might be nice for wiring a layout at quite a saving.The problem,if that is,is that these wires are aluminum.
My question is if aluminum wiring is as dependable and lasting as copper for one and can it carry the same load for a given gauge.I believe solder wouldn’t work so I plan on using it for mechanical connections only like terminals,screw poles,etc.What do you modelers think?Thanks.
You could probably use the aluminum wire for low-voltage applications under the layout, such as for a DCC power bus or for building lights, but I believe the National Electrical Code in the United States no longer allows the use of aluminum wire for household current applications, so you’d have to check with a licensed electrician if you want to use it for that purpose since Canadian laws may be even stricter than ours.
Aluminum was used for house wiring in the 1970s because the cost of copper was very high around that time and aluminum was cheaper. My house was built in 1975-6 and has aluminum wiring. It’s okay if you treat it properly. It is no longer allowed for house wiring. An aluminum wire cannot carry the same current as a copper wire of the same gauge. For instance, in a 15 amp house circuit, one would use #14 copper. With aluminum in a 15 amp circuit, one has to use #12 wire. That makes it more difficult to attach the wires to receptacles and switches, and takes up more room in the box. The most important thing with the house wiring is that you cannot use the same receptacles and switches and twist connectors (Marrettes) that you use for copper. Over time a layer of corrosion will build up between the wire and the terminal and cause problems. One has to use aluminum-compatable switches, receptacles and twist connectors.
Sorry, I got a bit off topic talking about house wiring. It shouldn’t be a problem for low-voltage, low-current model RR wiring. You are right, you won’t be able to solder to it. You will have to use connectors and terminal strips. You’ll need big terminal strips that can take that size of wire. I don’t think there would be a significant corrosion problem using connectors or terminal strips designed for copper with aluminum wiring in them with the low voltages and currents you would have. I gather that the wire you have is house wiring, so it is most likely 12 gauge. Even though the voltages and currents are lower than in a house, if you are using it on a DCC layout, I would treat it as #14 wire. You’ll find it stiffer and harder to work with than copper wire. Be careful not to flex it back and forth in one spot too much. It fractures easier than copper.
As I recall from having lived through the aluminum wire era, some odd properties of the aluminum wire lead to some electrical fires in recepticles after the wire would “shrink” under the compression of attachment screws eventually causing arcing between the wire and the attachment screws. I do not think that at our lower voltages that this will be a problem, but you may have to retighten screws on barrier strips and check crimp on connectors to avoid deterioration in contact and reliability. The price of the wire may make it attractive still for your applications.
I would be a bit leery about using it. Aluminum wire tends to break easily and isn’t the easist stuff to solder to. Also, it corrodes like crazy, quickly making any twisted connections unreliable. As for the thing about it in household wireing, aluminum was banned from use in household wiring by the very early 70’s. If you look in the wiring codes for 1974, you’ll see that it says ‘Do not use aluminum wire’ because it’s unreliable and is a fire hazard.
I believe one of the problems is a reaction between aluminum and copper or brass, so the connections have chemical problems dowm the line. They may not burn the layout down, but you would have to need the savings a lot to make it worth the risks.
Thanks everyone for your answers.Unfortunately,it confirmed what I suspected so I’ll stay away from using these wires.They would have saved me some $$$ but then I’m not interested in creating a potential hazard,let alone the headaches of troubleshooting.
I’ll still use them during construction for temporary connections and testing and in the worst case restrict their use to easily replaceable circuits,should they cause any problem.Thanks again.
The source of galvanic corrosion problems is humidity, with temperature changes a secondary source of problems with mechanical connections in electrical systems. Here in the dessicated desert, corrosion doesn’t happen (which is why they store retired aircraft out here.) In a tropical rain forest, you can almost see the corrosion forming!
That said, as long as you use fixed runs between terminal strips, and as long as you can inspect all the connections regularly, aluminum wire would be fine for all but the last ‘has-to-be-soldered’ link in track wiring, and for powering accessories with low voltage requirements. If you have a 120-volt utility circuit with outlets along the fascia (rather like a large, multi-outlet extension cord) do NOT use aluminum wire for that service. OTOH, if the wire is going to be flexed regularly, use stranded copper.
I have arranged all of my electricals to connect to terminal strips located behind removable panels in the fascia, so I can work on them from the aisleway. If you can arrange something similar, aluminum wire is fine now - and, if it later proves unsatisfactory, replacing it with something more suitable will be relatively straightforward.
Sell it to a recycler and use the money to buy copper.
Aluminum requires special procedures to handle it. The main reason it caused electrical fires is because everyone treated it like copper. You need to get things designed for use with aluminum, and any time Al and Cu wires come together, things get even more interesting.
The real issue with Al is corrosion. When it corroded, there was extra resistance at the joint. With 3 ohms of resistance at the joint, a 10A current would dissipate 300W of power at the joint. Only a matter of time before a fire occurs. I’ve heard that there was a grease that was supposed to be applied before the Marrette was twisted on, but many electricans neglected to do that…
Save yourself a lot of problems and just go all copper. At least you can eliminate bad connections and get the bonus of easy solderability.
I am an Electrical Consultant as well as a Master Electrician. The advice to sell the aluminum and buy copper is correct. As stated, the fire problem comes from the need to make the connections to aluminun cable. All connectors must be rated AL. Few, if any connectors, have this rating in small sizes required for model trains. Heating is also a serious problem with aluminum because it has higher resistance than copper conductors. Safety is the important consideration, but you are likely to have constant problems with loose connections too.
One thing though, are you sure the wire is aluminum and not tinned copper? You can tell by the weight and also if it takes solder OK. Tinned copper is a wonderful cable!
Now, why didn’t I think of that? [banghead] 99.44% of my (salvaged from communications cable) wire is tinned copper, which, at first glance, looks like aluminum. Just clip an end at an angle and look for that lovely reddish copper color. If it’s there, you’re in business!
If it isn’t, look up, “Metal recyclers,” in your Yellow Pages.
Chuck (modeling Central Japan in September, 1964 - with tinned copper wiring)
One could use the Al wire, if you use the anti-corrosion grease intended for it. Many new homes being built today have aluminum service connections (ie, from the power pole, to your meter box, and to your breaker box); my house was built in 2000 and has aluminum from the meter to the breaker box. That said, if it were me, i wouldn’t bother with the aluminum, I’d scrap it and go with copper. Small price to pay for years of reliability, and avoid potential hazards.