I am getting ready to re-configure my 6'x12' carpet central and I am debating between 18 or 16 gauge wire. 18 would definitely be easier to run under the carpet but is it heavy enough for this size layout?
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Probably 18 is OK. Use a few feeders to the track to equalize voltage drop.
Dale H
18 gauge wire is good for 16 amps in free air. 16 gauge wire can handle 22 amps in free air. Under carpet the wire will have a little more trouble "breathing" so you probably should derate it by 20% to compensate. The warmer a wire is, the more resistance it has. A CW-80 transformer can put out up to 4.5 amps.
Amps=Watts/Volts. 80watts/18volts=4.44 amps. Hope this helps.
David
Originally Posted by Up with UP:
18 gauge wire is good for 16 amps in free air. 16 gauge wire can handle 22 amps in free air. Under carpet the wire will have a little more trouble "breathing" so you probably should derate it by 20% to compensate. The warmer a wire is, the more resistance it has. A CW-80 transformer can put out up to 4.5 amps.
Amps=Watts/Volts. 80watts/18volts=4.44 amps. Hope this helps.
David
David,
The last time I checked the N.E.C. code book 18 gauge wire is only rated for about 8 amps, 16 gauge wire is rated for 12 amps, 14 gauge wire is rated for 15 amps.
I don't know where you are getting this free air stuff from? Unless you are using a table that I don't know of from the National Electric Code book.
Lee Fritz
Originally Posted by phillyreading:
David,
The last time I checked the N.E.C. code book 18 gauge wire is only rated for about 8 amps, 16 gauge wire is rated for 12 amps, 14 gauge wire is rated for 15 amps.
I don't know where you are getting this free air stuff from? Unless you are using a table that I don't know of from the National Electric Code book.
Lee Fritz
Maybe he got it from a table like this?
If your feeders are bundled, in a trough or touching one another they are not considered to be in free air.
Ken
Correct, you can't go wrong using the standard "rule of thumb" values of 20A for #12, 15A for #14, etc.
See Table 310-17 in your NEC. It is titled "Allowable Ampacities of Single-Insulated Conductors Rated 0 Through 2000 Volts in Free Air, Based on Ambient Air Temperature of 30C (86F)".
It is a 6X12 carpet layout. #18 would probably be OK,at most he would be running 1 train and a few accessories. I am assuming he is running a starter set transformer,6 amps max, but I should have asked. If he ran the wire then branched off like spokes on a wheel to 4 points on the layout,the wires size is effectively increased and voltage drop would be minimal since none of the runs are not very long. The track is also a conductor.
having said that #16 would be a better choice. Easiest and cheapest wire is to cut up a household extension cord. A 15 foot cord can be had for about $2,cut off the ends and use. I just assume he wanted to use #18 for some reason.
Dale H
