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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#41
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Tig welder extension cord
Ned Simmons writes:
On Tue, 04 Sep 2007 21:34:16 -0600, Joe Pfeiffer wrote: Ned Simmons writes: Seems like a perfectly good analogy to me. The cord is sized considering the nature of the load, not the capacity of the circuit that's feeding it. The welder in question draws about 30A @ 30% duty cycle. You're assuming the conditions of setting the duty cycle of the welder also apply to the duty cycle of the cord. I don't see *any* reason to believe that's going to be the case. When I see a duty cycle rating for an extension cord, I'll believe that it applies to it. In the mean time, I'll use a cord rated for the peak load that it will be called on to handle. See the NEC article on welders. It recognizes the intermittent nature of welding and allows conductors with an ampacity lower than the breaker on a welder circuit. You're right (and I'm surprised) -- the supply to a welder can be lower than called for by the peak current draw by roughly the square root of the duty cycle. Given that the duty cycle is defined over a ten minute period, this means you can run double the rated current through a cord for roughly two minutes! Yikes... Though that's also assuming the welder doesn't have a specified I1eff rating -- if it does, that trumps the calculation. |
#42
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Tig welder extension cord
On Wed, 05 Sep 2007 04:54:26 -0700, Larry Jaques
wrote: On Tue, 04 Sep 2007 23:28:21 -0400, with neither quill nor qualm, clare at snyder.on.ca quickly quoth: My little "MIG" welder runs on a 15 amp circuit on 110 volts. On a 50 foot 16 guage cord at full output the voltage drops to about 96 volts. That reduces the maximum current of an already borderline welder significantly.(14% voltage drop roughly 28% power drop?????) Time to bite the bullet and go buy a 12/3 contractor's extension cord. They're about $60 here in the States. Dunno 'bout Canuckistan. ================================================= ========== Save the Endangered Bouillons from being cubed! ================================================= ========== I've already got a couple of them. I don't use the light cords anymore for anything with a full load draw of over about 7 amps -- Posted via a free Usenet account from http://www.teranews.com |
#43
Posted to rec.crafts.metalworking
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Tig welder extension cord
On Wed, 05 Sep 2007 10:12:03 -0400, Ned Simmons
wrote: On Tue, 04 Sep 2007 23:28:21 -0400, clare at snyder.on.ca wrote: On Tue, 04 Sep 2007 20:00:07 -0400, Ned Simmons However, when running a welder on an extention cord, you want a cord capable of handling AT LEAST 120% of the expected load to reduce voltage drop. Unlike induction motors, most welders are tolerant of low input voltage. The 185T will operate on 208V circuits, so if it's being supplied by a typical 240V feed there'd have to be an awfully big drop to bother it. My little "MIG" welder runs on a 15 amp circuit on 110 volts. On a 50 foot 16 guage cord at full output the voltage drops to about 96 volts. That reduces the maximum current of an already borderline welder significantly.(14% voltage drop roughly 28% power drop?????) In this case, a 20 foot, 12 ga extension with a 38A load @ 240V results in a 2.5% drop, or 234V at the welder. Also note that the 185T is an inverter welder - it acts like a switching regulator and draws more current as the supply voltage drops, so I doubt you'd notice any difference at the output. I get about 30A running thru a 50ft, 16 ga extension for a 14V drop. Are you sure the whole loss is in the cord? Did you factor in both the power and the neutral? 100 feet of conductor in total. -- Posted via a free Usenet account from http://www.teranews.com |
#44
Posted to rec.crafts.metalworking
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Tig welder extension cord
On Wed, 05 Sep 2007 01:27:33 -0700, Gunner Asch
wrote: On Tue, 04 Sep 2007 23:21:46 -0500, zxcvbob wrote: (there was an experiment that went terribly wrong during the 1970's with using AL wiring for 15 and 20A circuits.) Bob Indeed. They are still finding them when the house burns to the ground. Gunner The EARLY aluminum wire was awfull. The later stuff is OK with the proper switches and receptacles, which did NOT exist when aluminum wiring was common. I don't like the stuff, but my home was wired with it and I'm NOT rewiring it. I am, however, replacing all devices with co/alr devices. -- Posted via a free Usenet account from http://www.teranews.com |
#45
Posted to rec.crafts.metalworking
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Tig welder extension cord
On Tue, 4 Sep 2007 22:47:45 -0700, "42etus"
wrote: And where do you have 20 amp breaker protection on domestic circuits????? In North America????? It has been commonplace, though not required, to wire outlets in homes on 20 amp circuits for years now, at least in the U.S. I'm talking Canada, where copper AWG14 and 15 amps is still the "standard". Virtually all domestic branch circuits are 15 amp fused(or breaker protected) 14 AWG copper or 12 awg Aluminum cable. Wrong! Typically residential wiring uses 12 AWG wire on 20 amp circuits for wall outlets. Aluminum wire is NOT allowed in residential wiring except as service entrance conductors and hasn't been for years. Virtually all computer power cords are 18AWG fine stranded copper, as are MOST lamp cords and many light duty extention cords. That is the point I was trying to make. Virtually all domestic 110 volt receptacles are 15 amp and it is AGAINST CODE to install 20 amp receptacles on a 14 guage 15 amp circuit. Yes, but FWIW it is NOT against the NEC to install 15 amp receptacles on 20 amp branch circuits. I believe it still is in Canada. Our rules tend to be a bit more "conservative" than in the USA. The OCCAISIONAL dedicated circuit for things like room air conditioners are wired with 12awg and protected to 20 amp - using 20 amp receptacles and the odd "T" type power plugs That would be a very small A/C unit indeed since the NEC requires that an appliance on a dedicated circuit draw no more than 75 % of the circuit's rating, or in the case of a 20 amp circuit, 15 amps. An appliance that draws 15 amps is not likely to have a NEMA 5-20P (odd T type) plug. 42 Lots of window air conditioners up here, 10,000 BTU? are rated at something like 13 or 14 amps, and have standard 15 amp plugs - which fit just fine in a 20 amp plug. Many people have 20 amp circuits installed to run these to avoid the voltage drop associated with lighter wiring, and to handle the startup surge more effectively. -- Posted via a free Usenet account from http://www.teranews.com |
#46
Posted to rec.crafts.metalworking
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Tig welder extension cord
On Tue, 4 Sep 2007 22:59:02 -0700, "42etus"
wrote: Now I see from your header that you're in Canada. I don't know a thing about the Canadian codes, my experience has all been in the USA. All my comments were intended to remain south of the 48th parallel.grin 42 And I'm considerably south of that, too. 43° 27', North clare at snyder.on.ca wrote in message .. . On Tue, 4 Sep 2007 20:03:48 -0700, "42etus" wrote: I think you guys missed my point. The OP seemed to be concerned that he was going to have a cord rated at 25 amps protected by a 50 amp breaker. What I meant to point out is that it is very common and allowed by the NEC to have cords supplying appliances that are rated less than the breaker supplying the circuit. Most household appliances, toasters, lamps, radios, computers etc all have power supply cords that are not rated for the 20 amps that wall outlets are capable of supplying. Can you imagine your electric razor having a 12/3 SJO cord just because your outlet in the bathroom was on a circuit protected by a 20 amp breaker? That would make shaving each morning a real PITA. 42 And where do you have 20 amp breaker protection on domestic circuits????? In North America????? Virtually all domestic branch circuits are 15 amp fused(or breaker protected) 14 AWG copper or 12 awg Aluminum cable. Virtually all computer power cords are 18AWG fine stranded copper, as are MOST lamp cords and many light duty extention cords. Virtually all domestic 110 volt receptacles are 15 amp and it is AGAINST CODE to install 20 amp receptacles on a 14 guage 15 amp circuit. The OCCAISIONAL dedicated circuit for things like room air conditioners are wired with 12awg and protected to 20 amp - using 20 amp receptacles and the odd "T" type power plugs - | u -- Posted via a free Usenet account from http://www.teranews.com -- Posted via a free Usenet account from http://www.teranews.com |
#47
Posted to rec.crafts.metalworking
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Tig welder extension cord
On Wed, 05 Sep 2007 09:22:24 -0500, "Pete C."
wrote: clare, at, snyder.on.ca wrote: On Tue, 4 Sep 2007 20:03:48 -0700, "42etus" wrote: I think you guys missed my point. The OP seemed to be concerned that he was going to have a cord rated at 25 amps protected by a 50 amp breaker. What I meant to point out is that it is very common and allowed by the NEC to have cords supplying appliances that are rated less than the breaker supplying the circuit. Most household appliances, toasters, lamps, radios, computers etc all have power supply cords that are not rated for the 20 amps that wall outlets are capable of supplying. Can you imagine your electric razor having a 12/3 SJO cord just because your outlet in the bathroom was on a circuit protected by a 20 amp breaker? That would make shaving each morning a real PITA. 42 And where do you have 20 amp breaker protection on domestic circuits????? In North America????? Virtually all domestic branch circuits are 15 amp fused(or breaker protected) 14 AWG copper or 12 awg Aluminum cable. Virtually all computer power cords are 18AWG fine stranded copper, as are MOST lamp cords and many light duty extention cords. Virtually all domestic 110 volt receptacles are 15 amp and it is AGAINST CODE to install 20 amp receptacles on a 14 guage 15 amp circuit. The OCCAISIONAL dedicated circuit for things like room air conditioners are wired with 12awg and protected to 20 amp - using 20 amp receptacles and the odd "T" type power plugs - | u -- Posted via a free Usenet account from http://www.teranews.com Every single "domestic" circuit in my house is 20A. There is no 14ga wire anywhere in the house. It was even this way when I bought the house, before I replaced the main panel. Pete C. The USA and Canada are different then, in more ways than I was aware. -- Posted via a free Usenet account from http://www.teranews.com |
#48
Posted to rec.crafts.metalworking
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Tig welder extension cord
On Wed, 05 Sep 2007 11:14:27 -0500, zxcvbob
wrote: I'm not really up on Canadian electric codes, but they are different than in the USA: Canada only recently changed to allow 20A receptacles that will accept a 15A plug. Previously, 15A circuits could only have 15A receptacles (just like USA) and 20A circuits could only have 20A-only receptacles (I'm not sure those even exist in the USA) Also they wire their kitchen countertop outlets different -- IIRC they use 15A duplex receptacles and split them, using an "edison circuit" (each pair of outlets has 240V available between them) That would come in really handy if you wanted to replace one with a 240V receptacle for one of those 3000W British electric kettles that will boil a quart of water in 10 seconds ;-) Bob Yes, splits are MANDATORY in Canadian kitchens, and I believe our code requires more outlets in a room than the US does as well. Likely allows fewer outlets per branch circuit too. I believe we also allow fewer wires in a box of a given size. I know a LOT of devices that are "legal" in the USA do not get approval here. -- Posted via a free Usenet account from http://www.teranews.com |
#49
Posted to rec.crafts.metalworking
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Tig welder extension cord
On Wed, 05 Sep 2007 22:01:51 -0400, clare at snyder.on.ca wrote:
On Wed, 05 Sep 2007 10:12:03 -0400, Ned Simmons wrote: I get about 30A running thru a 50ft, 16 ga extension for a 14V drop. Are you sure the whole loss is in the cord? Did you factor in both the power and the neutral? 100 feet of conductor in total. Yup. This calculator says 33A to get a 14V drop... http://www.powerstream.com/Wire_Size.htm -- Ned Simmons |
#50
Posted to rec.crafts.metalworking
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Tig welder extension cord
On Wed, 05 Sep 2007 22:07:13 -0400, clare at snyder.on.ca wrote:
On Wed, 05 Sep 2007 01:27:33 -0700, Gunner Asch wrote: On Tue, 04 Sep 2007 23:21:46 -0500, zxcvbob wrote: (there was an experiment that went terribly wrong during the 1970's with using AL wiring for 15 and 20A circuits.) Indeed. They are still finding them when the house burns to the ground. The EARLY aluminum wire was awful. The later stuff is OK with the proper switches and receptacles, which did NOT exist when aluminum wiring was common. I don't like the stuff, but my home was wired with it and I'm NOT rewiring it. I am, however, replacing all devices with co/alr devices. Even CO/ALR devices are not immune to trouble. I'd still MUCH prefer it if the folks plagued with AL wiring would rip it all out and start over. But for some strange reason people don't want to spend all that money on a job they can't see any benefits from - at least not until after the fire. Go figure... The only safe way to handle it is to have all the device locations (receptacles switches and lights) pigtailed to copper wires for the device connections with compression splices - Amphenol makes the special splices, the powered crimpers to apply them, and the heat-shrink insulation sleeves on top. You have to take a factory course and be certified by AMP to buy the supplies and to do the work. For minor moves and changes where you don't want to pay the crimping guys, the wiring has to be pigtailed out with special purple NoAlOx compound filled wirenuts with extra strong springs - Ideal makes them. -- Bruce -- |
#51
Posted to rec.crafts.metalworking
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Tig welder extension cord
On Wed, 05 Sep 2007 23:37:26 -0700, Bruce L. Bergman
wrote: On Wed, 05 Sep 2007 22:07:13 -0400, clare at snyder.on.ca wrote: On Wed, 05 Sep 2007 01:27:33 -0700, Gunner Asch wrote: On Tue, 04 Sep 2007 23:21:46 -0500, zxcvbob wrote: (there was an experiment that went terribly wrong during the 1970's with using AL wiring for 15 and 20A circuits.) Indeed. They are still finding them when the house burns to the ground. The EARLY aluminum wire was awful. The later stuff is OK with the proper switches and receptacles, which did NOT exist when aluminum wiring was common. I don't like the stuff, but my home was wired with it and I'm NOT rewiring it. I am, however, replacing all devices with co/alr devices. Even CO/ALR devices are not immune to trouble. I'd still MUCH prefer it if the folks plagued with AL wiring would rip it all out and start over. But for some strange reason people don't want to spend all that money on a job they can't see any benefits from - at least not until after the fire. Go figure... The only safe way to handle it is to have all the device locations (receptacles switches and lights) pigtailed to copper wires for the device connections with compression splices - Amphenol makes the special splices, the powered crimpers to apply them, and the heat-shrink insulation sleeves on top. You have to take a factory course and be certified by AMP to buy the supplies and to do the work. And they are no safer than a properly installed co/alr. My dad was an electrician through the aluminum years here in ontario. For minor moves and changes where you don't want to pay the crimping guys, the wiring has to be pigtailed out with special purple NoAlOx compound filled wirenuts with extra strong springs - Ideal makes them. -- Bruce -- -- Posted via a free Usenet account from http://www.teranews.com |
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