Extension cord question

[90blackcrx]

I need to a run an extension cord for my miller 180sd, it needs to be atleast 100ft. Now in the manual it says the extension cord should be 8gauge and the max length can be 147ft. But now I'm hearing 8 gauge is to small, any inputs on my situration ?

http://i3.photobucket.com/albums/y72/90blackcrx/ada.jpg

[Fishy Jim]

See the fine print at the bottom Bob?

What you're talking about doing qualifies for the exception. They're talking about the conductors in the house wiring.

[90blackcrx]

I caught that, so what size gauge wire would I need then for a 100ft extension cord or even a 50ft cable ?

[MAC702]

Now in the manual it says the extension cord should be 8 gauge and the max length can be 147ft.

Don't let someone try to outthink the factory engineers on this one. Go with the manual's recommendations; they are there for that reason.

[90blackcrx]

Don't let someone try to outthink the factory engineers on this one. Go with the manual's recommendations; they are there for that reason.

MAC I'm going to email you. Anyone else have any input ? I really need to know asap and I'm pretty much lost on this one. I mean can someone explain to me why I can run wire from my circuit panel 100ft but I can't run an extension cord ?

[MAC702]

Maybe I missed too much of the original issue. What are your needs? And what do you have to work with?

[90blackcrx]

I will be running a miller 180sd welder. My receptacle is about 100ft away.

Andy have any thoughts about the extension cord ? I contacted miller but they did not get back to me yet.

[90blackcrx]

Pretty sure the extension cord would cause to much of a voltage drop, any opinions ? Am I right ?


How accurate is this ?
http://www.electrician.com/vd_calculator.html

[hankj]

Thought we went through this exercise on the other board?

The drop calculation is correct. It's well within the range of the welder's tolerance. If you have decent line voltage, like most areas of the US, you should have no trouble producing maximum output from the welder in those rare cases where it may be needed.

Hank

[ivans]

Extension cord size

If you need to know the minimum size for a 100 foot long extension cord for your 180SD, you're going to need some info first:

• What is your available voltage at your outlet or breaker panel?
• What is the voltage drop for the intended gauge wire?
• What is the minimum voltage your 180SD will operate at?
• What is the amperage required by the 180SD?

The link you posted to the voltage drop calculator is a good one: Voltage Drop Calculator

I can answer a few of those questions from the Miller web site:
Maximum Input Amperage: 54
Minimum Voltage: 208

I will assume you have 240 volts available at your panel or outlet, putting these figures into the voltage drop calculator shows that 8 gauge would have a voltage drop of 8.4 volts; resulting in 231.6 volts available to the welder. From a voltage drop standpoint this works fine, but the suitability of the 8 gauge wire in relation to short circuit protection may be a different matter. 8 gauge is good for up to 50 Amps if the cord consists of no more than three conductors - so you're OK there too. Make sure it is protected by a breaker no greater than 50 amps and you should be OK with 8 gauge. That will not quite suit the full input requirement of 54 amps which will limit the ultimate output of the welder, but as long as you don't need the complete max output you should do fine.

[90blackcrx]

I see what you are saying about the 240v, but say I only was using 15v at the welder, would I still see that voltage loss of 8 ? Or does it change when the voltage lowers ?

I was going to use a 60 amp breaker just because I thought the 180sd maxes out like at 54. So if the machine maxs out at 54 and if I used the 8 gauge wire, what would I be able to max out at ? I mean is it really starving my machine that bad ?

Ivan is there any other way I could contact you, aol instant messenger ?

Thought we went through this exercise on the other board?

The drop calculation is correct. It's well within the range of the welder's tolerance. If you have decent line voltage, like most areas of the US, you should have no trouble producing maximum output from the welder in those rare cases where it may be needed.

Hank

Line voltage should be good because I'm getting this line done soon, so its not old and nothing else is taking up voltage off the line. The main 240v receptacle is only about 3ft away from my main panel. So there should be no voltage drop there.

Hank do you have any other means of contact ? I need to find out more abou this asap.

You can email me at [email protected]

Sorry I can't answer all the questions but I can tell you this

My 240v receptacle will have 240v at it, I'm using a 180sd welder, and I want to use an 100ft extension cord. Thats basically all I can say, and I just want to know if this will starv my machine ?

[ivans]

I see what you are saying about the 240v, but say I only was using 15v at the welder, would I still see that voltage loss of 8 ? Or does it change when the voltage lowers ?

Voltage loss is mostly a function of resistance which is more or less constant for a given wire gauge. You would still see the voltage loss of 8.6 volts at a 15v input.

I was going to use a 60 amp breaker just because I thought the 180sd maxes out like at 54. So if the machine maxes out at 54 and if I used the 8 gauge wire, what would I be able to max out at ? I mean is it really starving my machine that bad ?

No, it's not starving your machine unless you are turning your weld current up to it's max. The amount of current the welder requires for the cord is in relation to the amount of welding current your weld process requires. If you don't turn the machine all the way up, you'll have no problem. I would expect that you should be able to go to around 90% of rated output. Remember that the circuit breaker is really intended to protect the wire between it and the load. If too much current is flowing thru the circuit breaker, it trips before the wire becomes hot enough to cause a fire. So in a extreme example; if you were trying to run your welder on a 16 gauge extension cord with a 50 amp breaker, the cord would become hot enough to burn through its insulation before the breaker tripped.

The reason I recommended a 50 amp breaker was to protect your 8 gauge cord - not to limit your welder. The 8 gauge wire (no more than three conductors, this refers to the individual wires i.e. Hot 1, Hot 2 and ground) is rated for 50 amps of current carrying capacity. It should be protected at that level to avoid the aforementioned fire problem

If you want to run your welder at its full rated output, you'll need to go to 6 gauge wire so you can step up to a 60 amp breaker. Other wise if you can run it at 90% then the 8 gauge will be fine and save you a couple of bucks too

[Fishy Jim]

"Remember that the circuit breaker is really intended to protect the wire between it and the load. If too much current is flowing thru the circuit breaker, it trips before the wire becomes hot enough to cause a fire."

This is completely absurd!

The breaker is there to prevent a short from causing a fire. If you ran too high a load through too small of a wire and didn't manage to hit 50A, you could be incinerating things without ever tripping the breaker (think of a toaster, electric oven, electric stove, rod oven, etc). Certainly melting the insulation off the wire would be a primary concern.

I've shown Bob the wattages of loss that smaller gauge wire will consume - it's quite substantial when you think about it in the fact that it's electricity you're using, but is never making it to your machine. An 8 gauge wire may be ok for a short run, and could give you enough voltage to get the job done, but the line loss is equal to running a 400W light on the same circuit. That's a lot of electricity to be paying for that never makes it to your welder.

[90blackcrx]

I talked to Hank over the phone and he set me straight, thanks once again Hank.

So I know I would see voltage loss if I maxed the machine out, but will I run into any problems welding thin metal ( when I have to turn my machine down low ) . Thats what I was getting at with the 15v , even though the welding machine might not work like that.

[hankj]

For the sake of accuracy, I'd like to point out that, per the NEC, Art. 310, Table 310.16, #8 is rated for 40 amps. #6 is rated for 50 amps. That article describes loads running at 80% of capacity continuously.

Welding machine loads are limited by the duty cycle of the machine. That's why #8's are allowed for 50 amp welding cicuits, per Art. 630 of the NEC.

It's not a real big thing, but people read these posts, and posted information of this nature should not only be corect, but the references to support the conclusions of the poster should be included, in my opinion.

Hank