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scottsdale
03-04-2005, 05:56 AM
ok for all that know more about electricity than me heres a question.If you take two pieces of 6/3 SO CORD and wire the ends together will it carry more amps,equal to or greater than 4awg.Wiring the ends so that you have two power input lines.

enlpck
03-04-2005, 09:00 AM
ok for all that know more about electricity than me heres a question.If you take two pieces of 6/3 SO CORD and wire the ends together will it carry more amps,equal to or greater than 4awg.Wiring the ends so that you have two power input lines.

About the same as 4awg. When paralleling conductors, they need to be derated slightly. THEORETICALLY, the parallel 6awg will carry about 20% higher current than single 4awg.

Not a good idea to parallel SO cord, though. The connections are tough to make up, and the lines need to be tied together to avoid tangling, which will make handling awkward.

Let me add that if you are thinkng about using two different feeder circuits (your wording isn;t clear) DO NOT DO IT. When paralleling feeds, they need to come from the same source, they need to be about the same length, and need to run as close to each other as possible, and each feed set needs to be balanced. Example: running several parallel sets of conductors for a 1000A three phase feed might be done with three parallel sets of conductors, with an A, a B, and a C phase conductor in each bundle. If not done this way, the power will not have a hope of balancing, and losses go way up due to magnetic effects. If fed from different points, or the lengths of the parallel paths differ by much, the load won't be shared effectively (hence the derating-- to allow for unequal load sharing which occurs even under ideal setup)

scottsdale
03-04-2005, 09:23 AM
thanks for information.What I'm trying to do is wire up a welder where I can move it from one location to another.I had just bought a 250 ft roll of SO 6/3 and wanted to make a 50-75 ft cord on it.I was planning on coming from same source a 125 amp breaker and possibly even soldering the two wire ends together and wire tie the cords together about every twelve inches.But I just wasn't for sure if it would equaly carry the load.

enlpck
03-04-2005, 12:13 PM
thanks for information.What I'm trying to do is wire up a welder where I can move it from one location to another.I had just bought a 250 ft roll of SO 6/3 and wanted to make a 50-75 ft cord on it.I was planning on coming from same source a 125 amp breaker and possibly even soldering the two wire ends together and wire tie the cords together about every twelve inches.But I just wasn't for sure if it would equaly carry the load.

You want to look into several things here:

Duty cycle of welding, max TYPICAL suplpy current, temp rating of cord, and voltage drop at max current. These all play a part, as a longer cord has higher drop, and even if it is 'ok' for the current safety wise (won't overheat) the drop may be enough to make the welder unusable.

You can run smaller cord, under NEC, for welderes than for constant load IF The duty cycle is derated. Cord length will be the killer here.

If the TYPICAL max load is within the limit for the 6/3, just fuse for the lower size.

In general, you want to follow the manual reccommendations for cable sizing and length, fo the welder to function properly and for safety.

scottsdale
03-04-2005, 12:58 PM
This would also apply to 4awg as well,right?

Sandy
03-05-2005, 11:53 AM
On the practicallity side, it seems like it's going to be an awfully cumbersome cord there. I'm just thinking about how you're going to serve up the ends. Strip out enough of each to be able to bring them both together into the plug and lugs-----------sounds like a wrestling match. And then the cord(s) is going to be heavier than necessary and awckward as heck to move around.

NnF
06-16-2005, 06:40 AM
:sleeping:

How about a ground wire?

6-3, has 3 wires (wow), you didn't say 6-3 with grd which would have 4 wires, when running 220 volts it only has the two power wire and a Neutral, yes the neutral is something like the ground, but it isn't a ground. This works on lower amperage draw units but for safety a ground is mandatory.

Make sure you have a separate green ground wire connected on both ends of the main feed wires and any extension cord you make up.

If you are hooking up 115V, which I'm thinking NOT, but the 6-3 will work with 1 Load, 1 Neutral and 1 ground.

Enlpck is right on the SO Cord when mentioning the connecting of ends. Soldering does not lend itself well to this type of cable and clamping of two of this type of wire in the same connector designed for one wire is not the thing to do. Poor connections can cause heating problems too.

Smart move, as stated earlier, would be to check the full load capability of the 6-3, check the full load amperage draw of your welder and compare.

Luck

Charles Brown
07-01-2005, 12:28 PM
How about a ground wire? 6-3, has 3 wires (wow), you didn't say 6-3 with grd which would have 4 wires, when running 220 volts it only has the two power wire and a Neutral, yes the neutral is something like the ground, but it isn't a ground. This works on lower amperage draw units but for safety a ground is mandatory. Make sure you have a separate green ground wire connected on both ends of the main feed wires and any extension cord you make up.

All the single phase 230V welding machines that I have seen (under 300 AMP) that have pigtails wired to them with only three prongs, not four. They all are shipped with the standard 50A-250V "welder's plug," which has two parallel blades, one wide, one narrow, and a U-shaped blade in the middle.

The plug instructions always indicate wiring the green jacketed conductor in a 3 wire cable to the U shaped prong, wiring the black jacketed conductor to the wide prong, and wiring the white jacketed conductor to the narrow prong... not that the black or the white should make a difference in a HOT-HOT 220 circuit... but consistency is allowed.

What I don't understand is the quoted recommendation above, by NnF, where he states that a four wire 6-4 SO extension should be used, instead of a three wire 6-3? What would you do with the fourth conductor? Have it slit out of the cord near the plug and then screw it and unscrew it to the welder chassis each time it is plugged in?

That doesn't't seem practical or professional.

Nor does it seem reasonable to throw away the 6/3 cord with plug that shipped with the welder to exchange it for a 6/4, with a four prong plug. (I understand that Millers don't come with pigtails and plugs, but Lincolns and other brands do). To change to a four wire pigtail would require wiring the welder in a manner other than what the manufacturer intended. If that welder were to require warranty service (over the next 3 years for Lincoln), what would the response be when it is discovered that the welder was wired in another manner?

Even if adding a redundant chassis ground is clearly proved to have been harmless, what about the loaner welder you bring home while yours is being repaired? It will no doubt have the standard 3 prong welder's plug and pigtail, and now what will you do if you have a four wire receptacle? Rewire the rental unit too?

I can understand about the new NEC/NEMA requirements for fixed appliances like stoves, ovens, dryers, etc to have a separate chassis ground. In these applications, 6-3 building wire (which is 3 jacketed conductors and a bare ground) and 6-4 pigtail seem to be the new standard.

But on a partially portable welder like a MillerMatic 251 or a Power Mig 350MP, it doesn't make sense to me to go with 6-4 SO extension cable. Is there something I'm misunderstanding?