Non-electrician here. I know enough to be dangerous but am generally smart enough to ask questions first, so here goes with a little preface first:
I'm at the local orange box looking at the plethora of "heavy duty" extension cords -- the kind you roll out for your drill or saw (or both simultaneously) while you're say, building a deck. I understand with limited length you can pipe 15amps over 14ga wire, and 20amp over 12ga wire (at least in residential AC 110 wiring).
Now why do I see 15 amp rated extension cords of the same length (50ft. for instance) in all varieties of guage wires? If it's rated 15amps, then that's all you get no matter how thick the wire is, no? I would tend to get the thicker wire, but given the 14ga cord is $20 and the 10ga is $70, I'm leaning toward the thinner one.
Related question: would it be of any use or even safe to buy a 10ga 50' cord rated for 15amps, cut the plug and socket off, and attach 20amp plugs? The thickness seems to dictate it would work safely, but...?
Those cheap cords are more for the homeowner where thery're running a small drill for here and there projects. In the field the thicker cords are apropriate for running all day equipment. A lot of times extension cords are connected together to get the extra length in situations in the field. No one wants a cheap cord that voltage drop could cause damage to an expensive tool. There is times when other subs come to me to make a temp heavy duty cord to stop voltage drop and nuisance tripping.
Re: which ga. extension cord to buy/use?#20466 01/15/0301:05 PM01/15/0301:05 PM
Speaking of the big box... As far as I am concerned, the "crazy cord," or "wild wire" extension cords are a 'best buy.' They are 80-90ft. of 12/3 SJTOW wire, with molded-on ends. In simple english: -SJ, while lighter than S, qualifies as heavy-duty insulation, and will last; -T means shiny plastic on the outside, rather than dull rubber. I find it is more nick & cut resistant than rubber; -O means oil & gasoline resistant; and, -W means weather and sunlight resistant. (While tested to BEND at -40, it may not be very supple!) Finally, the single molded connector will fit in a number of things that multiple-tap ends will not. Typically, I will use one of these cords to serve several shorter (25') #14 cords. Cords smaller than #14 are too prone to damage. I have not seen a need for #10, even over a 250' run. (If I was running a pipe threader, I might re-consider; load is everything in terms of voltage drop!) I also have made extension cords using #12/2 zip cord (found with the Capri lights). I need this because not only do most of my tools have two-prong plugs, but many older homes have two-prong receptacles. I'd rather not use any adapters!