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#1
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110v extension cord sizing
So I know I'm over-thinking, but this will give a chance for some of the
folks with electrical religion to let off some steam. I have 3 machines that all need short (10 ft) extension cords: * 1.5 HP dust collector * 1 HP band saw * 1 HP jointer All run on 110 volts. I've read everything from "don't ever use extension cords with woodworking machines" to "14 gauge, 50 ft cord is fine." The dust collector says that its max draw is 18 amps. I can't find any extension cord, no matter what gauge, that says it is rated for more than 15 amps. That seems odd to me since an extension cord doesn't seem fundamentally different than Romex to me. Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord I was going to get 10 gauge for all of them, but the 10 is twice as much as the 12 and I'm not convinced I need the extra weight. Any thoughts? Mark |
#2
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"Mark Wells" wrote in message ink.net... So I know I'm over-thinking, but this will give a chance for some of the folks with electrical religion to let off some steam. I have 3 machines that all need short (10 ft) extension cords: * 1.5 HP dust collector * 1 HP band saw * 1 HP jointer All run on 110 volts. I've read everything from "don't ever use extension cords with woodworking machines" to "14 gauge, 50 ft cord is fine." The dust collector says that its max draw is 18 amps. I can't find any extension cord, no matter what gauge, that says it is rated for more than 15 amps. That seems odd to me since an extension cord doesn't seem fundamentally different than Romex to me. Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord I was going to get 10 gauge for all of them, but the 10 is twice as much as the 12 and I'm not convinced I need the extra weight. Any thoughts? Mark My thoughts are to remove the factory cords and add a 10-15 foot power cord. A little more work, but no fussing with extension cords either. Buy 12 guage extension cords, cut off the female plug and rewire to your machine. 12 guage cords are fine as long as the run is relatively short. 10 guage is overkill for 10-15 feet. Greg |
#3
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In article , "Greg O"
wrote: I prefer around a one foot power cord and a ten foot extension. When I go to move the machine it is easy to disconnect and not have to trip over the trailing cord. I use the heavy rubber cord protectors on the floor where I walk over the extension cord. Dick My thoughts are to remove the factory cords and add a 10-15 foot power cord. A little more work, but no fussing with extension cords either. Buy 12 guage extension cords, cut off the female plug and rewire to your machine. 12 guage cords are fine as long as the run is relatively short. 10 guage is overkill for 10-15 feet. Greg |
#4
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Richard Cline writes:
I prefer around a one foot power cord and a ten foot extension. When I go to move the machine it is easy to disconnect and not have to trip over the trailing cord. I use the heavy rubber cord protectors on the floor where I walk over the extension cord. Novel approach. About like what's been done to small kitchen appliances. But I use the cord as an indication of the machine's being unplugged when I'm changing blades, cutters, belts, etc. I drape the cord over the table so the plug is visible. If I can't see the plug, I won't work on the machine until I can see it. Charlie Self "Absolute faith corrupts as absolutely as absolute power." Eric Hoffer |
#5
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The nice thing about having the short cord on the tool then is you don't end
up walking back and forth to the wall plug all the time. Make it just long enough to loop it somewhere you can see it, and away you go! Clint "Charlie Self" wrote in message ... Richard Cline writes: I prefer around a one foot power cord and a ten foot extension. When I go to move the machine it is easy to disconnect and not have to trip over the trailing cord. I use the heavy rubber cord protectors on the floor where I walk over the extension cord. Novel approach. About like what's been done to small kitchen appliances. But I use the cord as an indication of the machine's being unplugged when I'm changing blades, cutters, belts, etc. I drape the cord over the table so the plug is visible. If I can't see the plug, I won't work on the machine until I can see it. Charlie Self "Absolute faith corrupts as absolutely as absolute power." Eric Hoffer |
#6
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10 gauge is good to about 25 amps sometimes 30 depending on the wire
insulation, the 12 gauge will be good to about 20 amps. you never want to push 14 gauge over maybe 12 amps. try to keep the wire at least 20 percent heavier than you need if possible. Extension cords use strand wire because it is more flexible. but it does not carry current as heavy as solid wire in romex. "Mark Wells" wrote in message ink.net... So I know I'm over-thinking, but this will give a chance for some of the folks with electrical religion to let off some steam. I have 3 machines that all need short (10 ft) extension cords: * 1.5 HP dust collector * 1 HP band saw * 1 HP jointer All run on 110 volts. I've read everything from "don't ever use extension cords with woodworking machines" to "14 gauge, 50 ft cord is fine." The dust collector says that its max draw is 18 amps. I can't find any extension cord, no matter what gauge, that says it is rated for more than 15 amps. That seems odd to me since an extension cord doesn't seem fundamentally different than Romex to me. Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord I was going to get 10 gauge for all of them, but the 10 is twice as much as the 12 and I'm not convinced I need the extra weight. Any thoughts? Mark |
#7
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Mark Wells wrote:
So I know I'm over-thinking, but this will give a chance for some of the folks with electrical religion to let off some steam. I have 3 machines that all need short (10 ft) extension cords: * 1.5 HP dust collector * 1 HP band saw * 1 HP jointer All run on 110 volts. I've read everything from "don't ever use extension cords with woodworking machines" to "14 gauge, 50 ft cord is fine." The dust collector says that its max draw is 18 amps. I can't find any extension cord, no matter what gauge, that says it is rated for more than 15 amps. That seems odd to me since an extension cord doesn't seem fundamentally different than Romex to me. Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord I was going to get 10 gauge for all of them, but the 10 is twice as much as the 12 and I'm not convinced I need the extra weight. Any thoughts? Mark 10 is overkill for that short of run. Get some 12g so or soj and some woodhead plugs and make your own. If you don't move your tools or put them in the same general spot then wire right to the motor. You would only need one plug per cord. |
#8
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Anyone advising against extension cords must live REALLY close to a power
plant, cause all wiring is essentially an extension cord The short answer: You can add 10 feet of 12 gauge on all three machines, no problem, but I agree with Greg that it is cleaner just to put longer cords directly to the electrical connections in the machine. No extra plugs to get dirty, trip over, and pay for. The longer answer: If you really are curious, what you care about is a) voltage drop, and b) internal heating. Internal heating is usually not an issue unless the cable is wound into a tight bundle or run in an enclosed space (like conduit). For stretched out cords, the heat generation is distributed over the length of the cord. You could (in theory, at least) run 15A of current thru miles of 14ga wire, and it would never overheat -- but the voltage drop would limit you way before that. Voltage drop: this is where length is important. Lower gauges are bigger wires, so their resistance is lower; for the same current, they have less voltage drop per length. 12 is about 1.7 ohms per 1000' (suprisingly little) while 14 is 2.6 ohms per 1000'. So a run of 14 will drop 50% more voltage than a run of 12. Ratings are pretty conservative: 100' of 14gauge at 15A will drop a reasonable 8V (4 on the hot, 4 on the neutral). 1000' would lose 80V -- which clearly would not work in a 110V system. This is why power transmission lines are high voltage (lowering the current for the same power), At low voltage, the losses would be way to large to tolerate. As far as prepackaged extension cords: One reason the cords may be rated is 15A is not the cable but the connectors (the plug itself). Connectors carry a rating, just like cable does, or outlets, etc. Usually, the rating has to do with the internal construction and regulatory testing. Often an plug carrying too much current will heat up long before the cord it is attached to. You will notice it when you grab the plug to unplug it -- it is warmer than expected. Vacuum cleaners are notorious for this, as the plugs have a tendancy to get uplugged with a quick yank on the cord (tsk, tsk). Time to fix the plug or get a new one. FWIW, Matthew "Mark Wells" wrote in message ink.net... So I know I'm over-thinking, but this will give a chance for some of the folks with electrical religion to let off some steam. I have 3 machines that all need short (10 ft) extension cords: * 1.5 HP dust collector * 1 HP band saw * 1 HP jointer All run on 110 volts. I've read everything from "don't ever use extension cords with woodworking machines" to "14 gauge, 50 ft cord is fine." The dust collector says that its max draw is 18 amps. I can't find any extension cord, no matter what gauge, that says it is rated for more than 15 amps. That seems odd to me since an extension cord doesn't seem fundamentally different than Romex to me. Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord I was going to get 10 gauge for all of them, but the 10 is twice as much as the 12 and I'm not convinced I need the extra weight. Any thoughts? Mark |
#9
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"Mark Wells" wrote in message ink.net... I was going to get 10 gauge for all of them, but the 10 is twice as much as the 12 and I'm not convinced I need the extra weight. 12 gauge all the way. I agree with Greg - replace the stock cord with a longer one. Either way, I think you will be happier making your own cords, instead of buying what's available in the hardware stores. You can buy heavy duty rubber covered SO cord at Lowe's or Home Depot and buy the connectors to fit also. SO cord is rugged and much more flexible than the things you get in the store. Bob |
#10
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Unless your DC is pretty close to the circuit box, you are already seeing
some voltage drop on 18a. Adding another 10' is not a great idea. I would recommend using a 10 gauge extension cord, or (even better) wiring the DC for 240v. A voltage drop calculator is at: http://www.electrician.com/vd_calculator.html You don't want to go over 3%. Length is house wiring, extension cord, and DC cord. And finally, I sure hope you are not using more than one tool on a 20a circuit, and that there is nothing else on the DC circuit, like lights. |
#11
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Mark Wells asks:
I've read everything from "don't ever use extension cords with woodworking machines" to "14 gauge, 50 ft cord is fine." The dust collector says that its max draw is 18 amps. I can't find any extension cord, no matter what gauge, that says it is rated for more than 15 amps. That seems odd to me since an extension cord doesn't seem fundamentally different than Romex to me. Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord I was going to get 10 gauge for all of them, but the 10 is twice as much as the 12 and I'm not convinced I need the extra weight. I really, really love the "don't use extension cords" types. The other choices are direct wiring, or replacing machine cords with longer ones. You're sizes are fine. AFAIK, ampacity of 12 gauge wire is sufficient for 20 amps, no matter which kind of cord you use, up to about 50'. It's in longer lengths that voltage drops become a problem. Going with the #10 for the dust collector is wise, because it allows for start-up surge. Charlie Self "Absolute faith corrupts as absolutely as absolute power." Eric Hoffer |
#12
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On Sat, 18 Dec 2004 02:38:21 GMT, "Mark Wells"
calmly ranted: So I know I'm over-thinking, but this will give a chance for some of the folks with electrical religion to let off some steam. Amen, Brother! I have 3 machines that all need short (10 ft) extension cords: * 1.5 HP dust collector * 1 HP band saw * 1 HP jointer All run on 110 volts. I'd run more wire, like 20', for each tool in case you want to swap them around at a later date. You could easily run 12ga for your short runs but if they'll get run over at all, 10ga would be the call I'd make. I have all 5' rubber-wheeled casters in the shop, so they're easy on cords when that happens. the cast iron wheeled tablesaur is the exception, but it has the armored, 3/4" thick 10ga cabling on it. Here is the cable rating for extension cords. ------------------------------------ | AMP RATING | LENGTH 25' 50' 100' | |------------------------------------| | 0-6 amps | gauge 16 16 16 | | 7-10 | 18 16 14 | | 11-12 | 16 16 14 | | 13-16 | 14 14 12 | | 17-20 | 12 12 10 | | 21-30 | 10 10 NO | ------------------------------------ (if you're not running a fixed width font, you'll get dizzy on that) Figures courtesy of the Grizzly G1012 instruction manual. I've read everything from "don't ever use extension cords with woodworking machines" to "14 gauge, 50 ft cord is fine." The dust collector says that its max draw is 18 amps. I can't find any extension cord, no matter what gauge, that says it is rated for more than 15 amps. That seems odd to me since an extension cord doesn't seem fundamentally different than Romex to me. It's stranded-wire vs. the solid-wired Romex, and it has an entirely different jacket. Other than being -totally- different animals, they're quite alike, just as you say. Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord I was going to get 10 gauge for all of them, but the 10 is twice as much as the 12 and I'm not convinced I need the extra weight. When in doubt, go heavy. What's an extra 30 cents a foot, anyway? I bought 50' of 12ga for my 220v bandsaw and dust collector, 25' apiece. The 30' cable on the table saw is 10ga and is nearly double the thickness of the new stuff. That cable is thick and protects the wiring inside better, so it's worth the few extra bucks. I think it was 25 or 30 cents a foot more, but if I needed a 100' extension cord for a power tool, I'd go with the thicker stuff despite its cost and weight. It could mean the difference between smoking the tool or running it nicely. The difference in price there would be more than enough to warrant the heavier gauge. -- Sex is Evil, Evil is Sin, Sin is Forgiven. Gee, ain't religion GREAT? --------------------------------------------- http://diversify.com Sin-free Website Design |
#13
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On Sat, 18 Dec 2004 02:38:21 GMT, "Mark Wells"
calmly ranted: Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord Let me restate that: Don't put -extension- cords on those machines, RECABLE them, wiring from the switch to the wall with new, high-quality cable and a grounded male plug on the end. -- Sex is Evil, Evil is Sin, Sin is Forgiven. Gee, ain't religion GREAT? --------------------------------------------- http://diversify.com Sin-free Website Design |
#14
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"Larry Jaques" wrote in message ... On Sat, 18 Dec 2004 02:38:21 GMT, "Mark Wells" calmly ranted: Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord Let me restate that: Don't put -extension- cords on those machines, RECABLE them, wiring from the switch to the wall with new, high-quality cable and a grounded male plug on the end. I have to disagree Larry. For a lot of us, our tools have to move around, in and out of parking places. Extension cords are much more versatile for that than hardwired cords. Properly made extension cords are every bit as good as a hardwired configuration and for us that have to deal with moving and storing, they're better. -- -Mike- |
#15
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On Sun, 19 Dec 2004 18:55:49 GMT, "Mike Marlow"
calmly ranted: "Larry Jaques" wrote in message .. . On Sat, 18 Dec 2004 02:38:21 GMT, "Mark Wells" calmly ranted: Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord Let me restate that: Don't put -extension- cords on those machines, RECABLE them, wiring from the switch to the wall with new, high-quality cable and a grounded male plug on the end. I have to disagree Larry. For a lot of us, our tools have to move around, in and out of parking places. Extension cords are much more versatile for that than hardwired cords. Properly made extension cords are every bit as good as a hardwired configuration and for us that have to deal with moving and storing, they're better. Because about 90% of extension cords out there are insufficient for use with a major power tool, you're asking for trouble telling people to use them. People tend to save money and an extension cord is the WRONG place to save it. Most are 18ga, some as heavy as 16, but VERY few are heavy guage wire. Those that do use it are usually found only in contractor sales areas or high-end shops and at 5 times the price of a homeowner cord. Most folks won't buy them. But that's your call, Mike. My general advice is "DON'T USE ONE!" unless I'm talking to someone who knows what voltage drops can mean and they have a contractor-grade cord. Fried motors are no fun and I won't be a party to someone frying theirs, thanks. -- Save the Endangered ROAD NARROWS! -|- www.diversify.com Ban SUVs today! -|- Full Service Websites |
#16
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"Larry Jaques" wrote in message ... Because about 90% of extension cords out there are insufficient for use with a major power tool, you're asking for trouble telling people to use them. People tend to save money and an extension cord is the WRONG place to save it. Most are 18ga, some as heavy as 16, but VERY few are heavy guage wire. Those that do use it are usually found only in contractor sales areas or high-end shops and at 5 times the price of a homeowner cord. Most folks won't buy them. But that's your call, Mike. My general advice is "DON'T USE ONE!" unless I'm talking to someone who knows what voltage drops can mean and they have a contractor-grade cord. Fried motors are no fun and I won't be a party to someone frying theirs, thanks. 5 years ago I would have come close to agreeing with you Larry - except that I'd have said "don't buy one, build one" in order to get a good heavy cord. But today, that's completely different. 10 and 12 gauge cords are commonly available from Wal Mart, Home Depot and every place that sells cords, and they're priced right down with what people always paid for junk 18 gauge cords. Check out the prices of 10 and 12 gauge cords next time you're out and about. They aren't even double the cheap things, let alone 5 times. Voltage drop across a 10 or 20 foot cord is something you'd have to look at as well. I don't know off the top of my head what it is, but that's a very short distance and I'm not so sure there's such a big issue at hand. On that point, I could be wrong, but it just does not seem there should be. I prefer to give advice that is appropriate. I'd suggest a fellow use a 10 or a 12 gauge cord. That, IMHO is a lot better advice than "don't do it". It can be better advice than to hardwire, especially in situations like I suggested in my reply. Which - by the way, you didn't address. -- -Mike- |
#17
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On Mon, 20 Dec 2004 13:03:13 GMT, "Mike Marlow"
calmly ranted: 5 years ago I would have come close to agreeing with you Larry - except that I'd have said "don't buy one, build one" in order to get a good heavy cord. But today, that's completely different. 10 and 12 gauge cords are commonly available from Wal Mart, Home Depot and every place that sells cords, and they're priced right down with what people always paid for junk 18 gauge cords. Check out the prices of 10 and 12 gauge cords next time you're out and about. They aren't even double the cheap things, let alone 5 times. The last one I specifically remember being advertised was a 25' contractor's cord for $30 in Ace Hardware in the last year or so. Then again, I haven't really looked into it lately, so perhaps you're right. I'll make it a point to look the next time I'm in a Borg or hardware store. Voltage drop across a 10 or 20 foot cord is something you'd have to look at as well. I don't know off the top of my head what it is, but that's a very short distance and I'm not so sure there's such a big issue at hand. On that point, I could be wrong, but it just does not seem there should be. Yes, the short run is definitely an advantage. I prefer to give advice that is appropriate. I'd suggest a fellow use a 10 or a 12 gauge cord. That, IMHO is a lot better advice than "don't do it". It can be better advice than to hardwire, especially in situations like I suggested in my reply. Which - by the way, you didn't address. Perhaps you underestimate human nature. Telling someone to get a specific cord, then watching them eye prices and grab the cheaper longer one, precisely the wrong thing to do and against your advice, is what too often happens. I give advice for worst-case scenario and consider it appropriate. Obviously, your and Charlie's methods differ. C'est la vie. P.S: GWB would have said "misunderestimate" there. -------------------------------------------------------- Murphy was an Optimist ---------------------------- http://diversify.com Comprehensive Website Development |
#18
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"Larry Jaques" wrote in message ... On Sat, 18 Dec 2004 02:38:21 GMT, "Mark Wells" calmly ranted: Here's what I was thinking * dust collector - 10 gauge, 10 foot extension cord * band saw - 12 gauge, 10 foot extension cord * jointer - 12 gauge, 10 foot extension cord Let me restate that: Don't put -extension- cords on those machines, RECABLE them, wiring from the switch to the wall with new, high-quality cable and a grounded male plug on the end. I have to disagree Larry. For a lot of us, our tools have to move around, in and out of parking places. Extension cords are much more versatile for that than hardwired cords. Properly made extension cords are every bit as good as a hardwired configuration and for us that have to deal with moving and storing, they're better. -- -Mike- |
#19
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Most of the problems with extension cords is in the plugs, not the cord.
25' of #14 under full load for a piece of equipment with a 5-15 plug (12a) drops about 1.8v. Bump that up to #12 and you drop 1.18v |
#20
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I wondered about that. Is there a reason that 20 amp outlets and plugs
aren't more common? Mark "Greg" wrote in message ... Most of the problems with extension cords is in the plugs, not the cord. 25' of #14 under full load for a piece of equipment with a 5-15 plug (12a) drops about 1.8v. Bump that up to #12 and you drop 1.18v |
#21
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Mark Wells asks:
I wondered about that. Is there a reason that 20 amp outlets and plugs aren't more common? Mark "Greg" wrote in message ... Most of the problems with extension cords is in the plugs, not the cord. 25' of #14 under full load for a piece of equipment with a 5-15 plug (12a) drops about 1.8v. Bump that up to #12 and you drop 1.18v Cable costs more, is harder (slightly, but harder) to wire to receptacles and switches. Charlie Self "Political language... is designed to make lies sound truthful and murder respectable, and to give an appearance of solidity to pure wind." George Orwell |
#22
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I wondered about that. Is there a reason that 20 amp outlets and plugs
aren't more common? There is very little that actually requires the NEMA 5-20 and some things that do, cheat. The code is very permissive about allowing 5-15s on 20a circuits but just be sure to buy the spec grade or better, not the 43 cent one. |
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