I’m really confused on this one. Why do extension cord manufacturers not put sensible ratings on their cords.
I need to upgrade mine, so am looking at buying some 12 gauge extension cords. Couldn’t believe the ratings on the cord packages.
16 gauge rated 13 amps (makes sense)
14 gauge rated 15 amps (makes sense)
12 gauge rated 15 amps (HUH? Shouldn’t this be 20 amps?)
10 gauge rated 15 amps (Double HUH? Shouldn’t thib be 30 amps?)
What’s up with that? Do they just put crappy ends on the heavier gauge cords or what?
What’s the point in buying a 10 gauge cord that’s only rated for 15 amps? I need a cord to run a pressure washer that draws 17 amps. I’m gonna go with at least a 12 gauge cord (matching the cord on the washer), am I gonna have to cut the ends off and put 20 amp capable plugs on the cord after I buy it or what?
Replies
It could be how long the cord is the longer the cord the less amp you can use it for. 50ft 12 gage cord will handle more amps then 100 ft 12 gage cord. Also the wire that is in it will make some differance as to the amps it can handle for each gage.
Check to see if those 12 guage and 10 guage extension cords aren't either 'long', like 100+ feet (in which case I think you need a heavier cord to reduce voltage drop), or, rated for 300 volts.
Phill Giles
The Unionville Woodwright
Unionville, Ontario
Good idea. That was my first thought, but even the 2 or 3 foot long triple tap extensions are rated 15 amps for 12 gauge wire.
David seems to have hit it spot on. That the plug style is only approved for 15 amps.
The standard 120-volt plugs (two vertical blades and a round ground prong) is what they put on the cords because then they fit into any receptacles. And many of those receptacles are only rated to 15-amps and/or there is 14-gauge in the wall. A heavier gauge extension cord, with a dedicated 20-amp plug (a regular one but with one vertical blade turned horizontal) could be rated for 20-amp use. But you couldn't plug it into 99% of the 120-volt receptacles out there.
Amperage-wise, no problem to use the 12-gauge or 10-gauge cord IF plugged into a 20-amp 120-volt circuit. But voltage drop is another issue. The quick check would be to put a 3-to-1 splitter at the pressure washer end and see, with a voltmeter, what voltage you get when it is running. If you have 120 at the house, without it running, and 112-115 at the washer when running, great.
If you get below 108 at the washer, you need bigger cords or a shorter run so as not to have so much voltage drop.
I have, at times, run two cords in parallel from the same receptacle and then plugged a 6-to-2 outlet tap into the female ends of the extension cords. (Those 6-outlet taps have two sets of male blades on the back. I've run double 10-gauge and/or 12-gauge extension cords this way for 300 feet with little voltage drop. THERE IS A DANGER TO THIS. The danger is if someone unplugs only one of the male ends of the extension cords. That unplugged end will be at 120-volts. So if there is anyone else around who hasn't been briefed, sign it, tape them together so pulling one pulls both, or just don't do it. Just go buy some 6- or 8-gauge Sj cord (for like $2/foot?) and affix the plugs on each end.
In either of those cases (double cords or really heavy gauge), go for the receptacle closest to the C/B panel, not closest to the jobsite. Because your wiring is meatier than what's in the wall (max 12-gauge).
Thanks for the idea on testing voltage.
I think you're absolutely right on the limitation being the cord end, which is designed to fit in 15 amp outlets. Found some 12/3 cords w/ twist-lock ends and they're rated for 20 amps to 50' and 15 amps if 100' long. They even have some 25' ones that are rated at 25 amps.
Anyway, I think I'll buy a 50' 12 gauge cord, or 2 25' cords and try using the multi-meter to make sure their isn't ecessive power loss when using it/them.
It'll plug into a 20 amp outlet wired w/ 12-2 wire w/ no other loads while in use, so should be ok. Right now I just don't use it with an extension cord, and it still occassionally pops the breaker.
I probably should see if I can rewire the motor to 220 and just put in an outlet specifically for this. I don't have an ampmeter, but assume it's pulling at least the 17 amps the nameplate says it is.
" I don't have an ampmeter, but assume it's pulling at least the 17 amps the nameplate says it is."
No, it will be much more or much less.
That 17 amps is at the rated load. Sounds like a 1.5 hp motor. So only when it has a 1.5 hp load will is draw that amount of current.
When it first starts it will be drawing 5-6 times that for a couple of seconds.
When it is running, but not cutting it will probably be drawing about 3-5 amps as the only work it is stiring the air and the friction in the belt and bearings.
Only when cutting under load will it start to reach rated load. And then you can push it harder and get even more power out of it for a short time.
Actually, it runs a pressure washer, it's a Baldor 2HP motor. So, it's under load whenever it's on. The couple times it's popped the breaker have been when it sits too long w/o my pulling the trigger on the spray gun. So the load must increase. Though the motor sound is constant and it never seems to bog down.
About time I wired in some more outlets in my garage. Most of the outlets in my house use push in connections, and rely on those to transfer power to the next outlet.
My exterior outlets are on a gfi breaker that also runs the bathroom outlets, that one'll pop sometimes, so I plug it in the garage, into a circuit, that unless I've missed something, only has 1 outlet and the fireplace fan on it. Not sure how it's wired, but it's possible there's some similar restriction that limits the power transfer. I did pull that outlet and put a 20 amp one in.
Right now I'm using some 12-2 house wire with good plug ends on it as a temporary cord, that seems to have fixed the problem, but isn't something I wish to use for long.
Would it be logical to put a pressure switch on the washer hose ? Power off when you are not pulling the trigger...
Can't we all just get a log ? - Paul Bunyon
Quittin' Time
I don't know if it'd be logical, because I would think the constant on off cycling of the pump and motor everytime you released the trigger would likely shorten their life.
But, it may make sense to put a switch on the nozzle so it's easy to switch it off w/o having to walk 30' back to the pump each time. I only have 1 hose and 1 nozzle, so they're left connected all the time anyway.
Actually I like that idea, thanks.
I would put a relay switch in at the motor.
So that the motor gets full power when running. Rather than the power having to go through the line to the switch at the wand, then back to the motor.
Can't we all just get a log ? - Paul Bunyon
Quittin' Time
That makes even more sense. After posting I thought, do I really want 120VAC on the end of a hose??????
Nope, I don't.
Those push in contacts are bad news. They may work ok for the 75 watt table lamp and the table radio.
But they are no good for heavy loads. The connections will get hot under load. And with each one you have a little more resistance.
Also GFCI will not trip from overload, only leakage currents.
For loads like this the most direct route, with the heaver wire is the best way to go.
Yeah, hate those push in connections.
Still don't understand why they meet code, they're nothing but trouble.
I've been gradually replacing the outlets and switches in the house to get rid of them, but it's not a priority thing, so only gets done if I'm working on something else in the area at the time.
Have a drawer full of 20 amp outlets I got off ebay. Bought 30 and still have at least 20 of them.
My garage/shop is definately gonna see some serious rewiring. Well, after the master bedroom/walk in closet project is done. And, the yard is cleaned up for winter, and the firewood straightened out. And, well you get the idea.
Perhaps I should make a priority of replacing the bathroom outlets. There's only 2 of them that haven't been done yet. Already replaced the exterior outlets (one of which failed due to a connection pulling out), and one bathroom outlet. Replacing 2 outlets would likely end the problems with the exterior outlets.
Oh, a seperate question.
I just picked up a 1hp shaper wired for 220VAC.
Hooked it up last night, and with the toggle switch off, the motor groans and barely turns the shaper bit. With the toggle on the motor runs great.
Any idea what would cause this?
My idea (haven't had time to take it apart yet) is that the switch has nearly failed and is allowing some power to go through in the off position. Any other ideas.
Just curious what else might cause this. I have a magnetic switch box I was gonna put on this machine eventually anyway, so that's no big deal, except that eventually now means before I use it.
My guess is that it is only running on 120, but how that is happening I don't know.
Did you get this from Frenchy?
It is a know fact that liberals don't know how to hook up anything <G, D, &R, VVF>.
If I remember correctly it is a jet. All of the jet stuff I have the switch is a 2 pole and breaks both sides of the line whether it is wired for 120 or 240.
But that really does not matter. But just breaking one side of the line is enough.
And if this is supply by a "pure" 240v circuit (2 hots and a ground, no neutral) it should not have any 120.
This is PURE 100%, FULL OF BS SPECULATION, but all I can think of off hand is that;
A) it is only a single pole switch or a 2 pole with one side bad along with,
B) either a insulation failure in the motor or more probably a bad connection at the junction box where it was switched from 120 to 240 and that there is a connection to ground.
Yep, got it from frenchy.
I'm not gonna complain to him though, he threw in 3 shaper cutters when he shipped it, and ate some extra shipping charges, won't tell me how much more it cost so I can't reimburse him.
Just hooked up a temporary power setup. I have a 40 amp 220 outlet in the garage, so I ran that to a box with a fuse block in it with 14 amp fuses, then to a box with the correct outlet for the shaper. Gotta quickly decide where I want it so I can hardwire it right. It's a mess with everything strung over the floor right now.
2 hots & a ground is all there is, and all 3 metal boxes in the circuit are grounded, so there's no way it could be running on 110.
Frenchy said it worked fine last time he used it, so I'll assume a connection somewhere vibrated loose in transit. Next day or two I'll start opening up boxes and seeing what I can see. Checking all the connections ect..
Can't blame the wiring on frenchy, he bought it, used it, then sold it to me, don't think he wired it.
2 hots & a ground is all there is, and all 3 metal boxes in the circuit are grounded, so there's no way it could be running on 110.
All grounds and neutrals end up in the same place at the service equipment (your main panel, for instance), so if there was a short inside the motor junction box to ground, you have 120V to ground (residential systems are only 120V to ground, though 240V hot-to-hot). There is a connection point inside a dual-voltage motor configured for 240V that will be 0V to ground (where the two windings connect to each other, as well as one end of the start winding), so if that connection was laying against the grounded motor frame, you would be getting 120V across one winding all the time if only one incoming line was cut with the switch, and normal operation with the switch closed.
I'd strongly suggest opening up the motor j-box, and checking for loose or bare connections, and look for some black soot or burn marks. And get a 2-pole switch.
Be seeing you...
Edited 10/16/2003 1:15:49 PM ET by Tom Kanzler
In case you're curious. I messed with it last night. Checked all the wiring and pulled the switch. Couldn't find any problems with the switch on the bench, but when I put it back together it grounded out and popped the fuse on that leg.
Just a single pull, single throw switch on one leg of 220.
Must have had something inside shake loose during transport. when I took it apart it must have moved and shorted to ground.
W/o the switch it works great. Now I've just gotta wire up the other switchbox.
What David Thomas said is correct. The limit being the rating of the cord cap, plug.