Still working on installing my exhaust fan. It required a dedicated 20A circuit so I ran #12 copper. The wiring from the unit appears to be #14 stranded. It's also silver colored but I don't know if that means it's aluminum. I need to connect one #12 wire to each of the #14s (so two wires per connector). What's the right connector to use for this?

  • What kind of exhaust fan requires 20A?!? Oct 24, 2012 at 12:42
  • 1
    I doubt the exhaust fan REQUIRES a dedicated 20A circuit if the internal wiring is 14 ga. It looks like your installation instructions have been LAWYERED! Oct 24, 2012 at 13:32
  • It also includes a heater and light, but I too was surprised by the size of the wires coming out after they insisted on 20A.
    – Brad Mace
    Oct 24, 2012 at 14:02
  • @ChrisCudmore stranded wire can carry slightly higher current compared to a solid wire of the same gauge.
    – Steven
    Oct 24, 2012 at 17:27
  • UMMMM a heater? That is the reason for the high current rating. A horse of a different color. Oct 24, 2012 at 22:21

3 Answers 3


That must be one powerful fan to require a dedicated 20 amp line. WOW. The silver wire you see is probably a tinned copper wire. (solder on the end of a stranded copper wire). To connect a 12 and 14 AWG set of wires together, you should use a yellow wirenut. If in fact the tinned conductor is smaller than a 14 AWG, you could use an orange wirenut. If you look on the package of wirenuts, it will give you a chart of the number and size of conductors the specific color wirenut will work with.

  • 2
    Twist the strands clockwise when looking at the end of the wire. It makes the strands act more like a single wire and helps in splicing them to other wires. Oct 24, 2012 at 14:31

You can also use whichever push-in connector makes sense for your application. I haven't had as good luck using them with stranded wire, but they are "allowed" and they do work.

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More information is available at http://www.idealindustries.com/prodDetail.do?prodId=in-sure&div=0&l1=push-in

  • 3
    While the stranded wire in this case is probably tinned, I would avoid push-in connectors for stranded. Too much chance of a stray strand missing the hole and shorting an adjoining wire. I would use a wire nut as per @shirlock homes answer. But I love push-ins for solid wire.
    – bib
    Oct 24, 2012 at 13:38
  • +vote, never use a push in for stranded wire, even tinned. On a 20 amp service, a push in is not a good idea. Oct 24, 2012 at 22:19
  • The push ins are really chancy on stranded, any motion and they will break. I'm tempted to vote the answer down, but it has zero votes now and will hopefully stay that way.
    – Bryce
    Oct 25, 2012 at 7:28
  • I'm not saying it's my first choice, but it is a choice. I have had it be finicky on old stranded wire, but new ones that you twist tightly before putting it in, those I've had good luck with.
    – Aaron
    Oct 25, 2012 at 18:45

You can properly use the push in connectors, from Ideal, if you are careful. Just twist the stranded wire clockwise to give it some solidness and push in same as solid. Technique and use described here on Ideal web site. http://www.idealind.com/media/pdfs/products/brochures/p-2854_in-sure_brochure.pdf Makes it very simple and quick.

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