extension cords

[facetious]

I have been wanting another 25 foot extension cord for the garage and saw some on sale and was looking at them and decided on a 12ga cord. A guy standing there was looking at cords also and while talking I said that it would be a good one to take camping if you are going to be in a Campground with power as thy tend to be 20 amp. He said that it was still only a 15 amp cord
because of the plug and that the wire may be good for 20 amp but the plug would overheat and burn up. I said that I thought it had to do with the type of outlet it would fit in and that the plug should be good for 20 amps. So the other night I googled it for fun and found something about everything but that.

So can you overheat a 15 amp plug on a 12 ga. cord by pulling 20 amps through it?

I don't think so.

A 14ga. would have been been good enough for what I need but it was on sale for 15.00 so what the heck never been sorry I had more than I needed.

[MrWolf]

I was worried about overheating so I just made my own extension cord with 12-2 and a metal quad box. Surprised how many times I have used it. No idea about cord ratings, sorry. Good luck.

[rancher1913]

a cord load rating is based on the wire size, and the end would have to be rated for the same amperage as the cord, in other words hes full of it.

they do make special 20 amp outlets that have one blade turned so that a small amp cord can not be used in it, keeps stupid people alive.

most home outlets are only 15 amp so using a 20 amp cord would be overkill but in the world of electricity, bigger is always better.

[Petrol & Powder]

1. Just because an outlet can supply 20 amp doesn't mean you will always be pulling 20 amps. If you have an outlet capable of suppling 20 amps and you put a 40 watt light bulb on the end of a short extension cord, you will not be pulling 20 amps.
2. The 20 amp plug & outlet combination have the horizontal neutral blade to distinguish a 15 amp from a 20 amp but generally it's the cord, not the plug, that's the weak link in that type of extension cord.
3. You can often make a far better extension cord than you can buy. Some SJ cord of the correct gauge (or similar flexible cable), the appropriate plugs and no more length than you really need will result in a far better cord than anything Walmart, Home Depot, etc. will offer for sale.

I have a few consumer grade extension cords that are cheap and convenient but if I need to carry serious current, I will make my own cord.

[Dapaki]

I just look up the derating schedule for stranded wire and follow it. I do generally buy COOW cord (12/3) for all my 20A needs and it will not overheat under use. Try that with a big box 12 ga cord from Home Depot and you will see it smoking in the winter.

[Mal Paso]

The condition of the plug is the biggest cause of failure. The 15A Plug on extension cords is the same size as the 20A plug. If it gets warm, you have problems. But the big thing is line loss like Petrol & Powder said. Even 12ga is not enough beyond 100 feet. There are 10ga extension cords to help with this. Harbor Freight has a 100 foot 10ga that goes on sale for $100 every so often.

[JonB_in_Glencoe]

The condition of the plug is the biggest cause of failure.

>>>SNIP
OR
...the condition of the receptacle ;)

[Ickisrulz]

they do make special 20 amp outlets that have one blade turned so that a small amp cord can not be used in it, keeps stupid people alive.


How do you figure?

[waksupi]

I needed a more or less permanent extension cord in my shop. I got out a roll of Romex, measured it out, and attached male and female ends. Shazam! Heavy duty extension cord.

[bangerjim]

I needed a more or less permanent extension cord in my shop. I got out a roll of Romex, measured it out, and attached male and female ends. Shazam! Heavy duty extension cord.

As long as you REALLY tighten the screws and watch for any corrosion. Putting solid Romex wire in a plug tends to put tension on it (the screws) that can wiggle wires loose - even with the cord retainer tightened (if it even has one). Loose connections = resistance = heating under a heavy load. Just check/tighten the screws every so often to be safe.

[leadeye]

This year a neighbor decided to supply her nephews trailer with electricity by taping Romex together with electrical tape and running it across my property with a series of garden hoses to supply water as well. My issue, other than having not been asked, was that it was a good 800 feet from her house to his trailer and that this was a fire risk in a field of dry grass. Maybe I was wrong about that. After being told to pound sand by the nephew, I ended up having to bring the police in and then found out that the nephews trailer was on my ground as well.

That was quite an extension cord!

[facetious]

I didn't think it would. All I needed is to reach across the garage. I have one 25 foot 14ga. that I use the most but sometimes I need to plug in two things and have to use a 50 foot cord and then you have all that cord to look out for. All the outlets are 15 amp but the ones on one side are on one circuit and the ones on the other side are on a different one so sometimes I have to plug something on one side and something on the other so I don't pop the breaker.

As for camping with more campgrounds having power I take a cord with to use a hot plate or a place heater if its cold out or whatever you may want to pug in and a 20amp is about all I would use if that.

[MrWolf]

Across a garage? I would run a line with its own fuse if possible. Run it outside the wall in the blue plastic tubing and mount boxes on wall instead of in it. I am not an electrician so take it with a grain. Good luck.

[Mal Paso]

Extension cord deal of the century, 2 50 foot 12ga 3 wire cords for $35 at Costco

[Mal Paso]

Across a garage? I would run a line with its own fuse if possible. Run it outside the wall in the blue plastic tubing and mount boxes on wall instead of in it. I am not an electrician so take it with a grain. Good luck.

Smurf Tube is an in the wall thing originally for inside cement. That grey conduit glues together just like PVC pipe. You can buy ready made 90* sweeps or heat it and bend it. Any conduit use THHN stranded wires as solid romex is a pain to pull.

[remy3424]

I was recently discussing extension cords with someone and I said that Fleet Farm had cheaper priced cords (sales prices anyway) on 12 gauge, they told me that the those likely have copper plated aluminum wire that couldn't carry the amount of current solid copper can....Any truth to this? Does the cord jacket say if the wire is solid copper or plated aluminum...or is plated aliminum even used in extension cords?

[Plate plinker]

Across a garage? I would run a line with its own fuse if possible. Run it outside the wall in the blue plastic tubing and mount boxes on wall instead of in it. I am not an electrician so take it with a grain. Good luck.

The blue tubing is for low voltage.....

[samari46]

If I remember right I was under the impression that if your are for an example using copper wire in an 15amp extension cord you have to go up one size if using an aluminum one. Now don't think I've ever seen an aluminum cord just copper. Another thing is that using a stranded copper wire allows it to carry more current than a same size in solid copper. Something about the stranded copper wire has more surface area. But then I could be wrong on both counts. Frank

[mattw]

Frank, you are correct. Electricity runs on the skin of the conductors. Stranded is better, fine stranded is even better. I make my extension cords from SO cable, it is fine stranded and therefore more flexible and the connections in the plug are more solid. Installing a 20 amp breaker in place of a 15 is not a good move unless you know the gauge of the wire and the distance of the run. Just like the hot plate that heats your mould... resistance generates heat and drops voltage. Resistance in this case is affected by wire guage and proper termination of the cable. Small gauge wires will get warmer as current goes up. I use many true 20 amp power cords and outlets at work. If the device is rated at 20 amps, it is really better to use a 20 amp plug and breaker.

Do not use aluminum for extension cords, it is not flexible and tends to crack with movement. Plus, if memory serves, it is not rated for that use. Copper is a much better conductor than aluminum and always will be.

[popper]

Don't think it's legal to use alum. wire in flexible extension cord. Al. wire stress cracks too easily. Cu coating is allowed in fixed wiring as the Cu coating doesn't 'crunch' under terminal pressure. Also don't think romex is allowed in conduit but I have pulled it through PVC pipe. Long extensions are ok for most lighting but motors need full voltage so oversize the conductors.
I bid the ceiling lighting for KCI (500 & 350 Merc vapor), guy that got the contract did Al wire and we got the cost + 10 to replace the Al.

[NyFirefighter357]

I think the guy was confused. If you use a 15amp outlet on a 20 amp circuit you will overheat the outlet if you draw 20 amps.

[MT Gianni]

Montana code doesn't allow 14 gauge wire in homes. All my outlets are 20 Amp. Never assume anything with electricity.

[samari46]

Mattw, thanks for confirming what I thought I knew. Frank

[Pinger87]

I remember the first time I realized extensions cords weren't all the same. Overheat that turned into an electrical fire. Wish this was more common knowledge

[Three44s]

I think we are missing the obvious here folks!

We do not need a bunch of long heavy power cords.

... Just plant plenty of Current Bushes .... in the right spots! ............

Three44s

[Pinger87]

I think we are missing the obvious here folks!

We do not need a bunch of long heavy power cords.

... Just plant plenty of Current Bushes .... in the right spots! ............

Three44s

Current bushes...Now that's a novel idea! You've got my vote.

[metricmonkeywrench]

I just recently added a 20a circuit with a switch and GFI to my main panel wired in with 12/3 cu. The switch/outlet i grabbed off the shelf were marked for 15/20a service.

somewhere about i have a chart with the wire size/amp load line loss for a given run