Cable Length

Wozzaaah · Jun 19, 2008

Folks, the work return cable on the Miller is a bit manky so I'd like to replace it. My question is, if I use 35mm2 cable, what's the maximum length I could sensibly go to bearing in mind that it's a 310A machine but I can probably only squeeze maybe 220A or so out of it? Would also probably do the MMA work lead at the same time. I think the leads are currently around 4 or 5m, what length leads do you have on your own big machines?

Welderpaul · Jun 19, 2008

Wozzaaah said:
what length leads do you have on your own big machines?

With scrap prices the way they are, and times being hard, i have to shorten mine by a foot each day and weigh them in. :vsad:

Drains · Jun 19, 2008

One of my migs has a big return lead - 10m or so, plus a total of around 6m from power source to tip. The other has a 20m lead to the wirefeed and a 3m earth. No probs on that. (all 35mm2). The cable isn't the problem, it's the contacts and the lug on the earth clip that get hot if they're not in tip top condition.

In the shipyards the leads from the power source to welding torch were miles long.

Someone with a brain in their head (Shenion, probably), will be able to calculate an "acceptable" voltage drop/length etc. It's probably out there in internet land too. Say 10 percent - so 2 volts off a 20v start... I can't be arsed to look now, you can do it.... :hug:

Archie · Jun 19, 2008

Well you could do some maths/physics and work out the likely drop over a length of cable. However, last time I tried getting all fancy with me A-level physics Si put me firmly back in my box so I'll leave it this time! :laughing:

Oh, mines 4m but I plan to add another 4 as I think I mentioned in Sparky's thread.

Archie · Jun 19, 2008

Haha. Comic timing, Si!

Paul. · Jun 19, 2008

archie.henderson said:
Well you could do some maths/physics and work out the likely drop over a length of cable. However, last time I tried getting all fancy with me A-level physics Si put me firmly back in my box so I'll leave it this time!

Oh, mines 4m but I plan to add another 4 as I think I mentioned in Sparky's thread.

Dont get too bogged down with theory, see what works, I have a single phase 140 amp inverter that has 25mtrs of leads with no noticeable drop in performance, the leads weigh more than the welder, probably worth more too,

Archie · Jun 19, 2008

TIG Paul said:
Dont get too bogged down with theory, see what works, I have a single phase 140 amp inverter that has 25mtrs of leads with no noticeable drop in performance, the leads weigh more than the welder, probably worth more too,

Don't worry mate. The less I have to think about theory the better! :laughing:

Besides, if you want it longer and you're worried about losses, just go for the next bigger thickness (50mm^2 at a guess).

Wozzaaah · Jun 19, 2008

Most welding cable seems to be 35mm archie, you can most likely get 50mm but I really don't need it, just thinking if I'm going to replace the cables I might as well make them as long as poss. Gonna replace the wah wah pedal cables too, they're also looking tired, thinking of using SY cable for that.

Archie · Jun 19, 2008

I completely agree on making them as long as poss. Not quite sure why I didn't pay the extra in the first place to have more than five meters of interconnecting cable.

The earth lead and interconnections on mine are 70mm but you can even get plugs for 95mm!!! No idea whether any 'normal' welder uses anything that big though!

Woody.v8 · Jun 19, 2008

I use 95mm on the dc 800 75mm on the synergic 500 and 50mm on the smaller stuff

Wozzaaah · Jun 19, 2008

Ummm......I've just realised how small 35mm2 cable actually is, it sounds big but it's actually pretty puny :ashamed:

. I reckon the stuff on the miller now is probably 75mm2 or so, possibly more.

Archie · Jun 19, 2008

Much more likely. An MB36 like the one on your Portamig has a 50mm cable in it. Not that that is much help as you can't see it to compare with.....

gavuk · Jun 20, 2008

our stores are much easier...600amp or 300 amp cable ,i can work that out :laughing:

Drains · Jun 20, 2008

Wozzaaah said:
Ummm......I've just realised how small 35mm2 cable actually is, it sounds big but it's actually pretty puny . I reckon the stuff on the miller now is probably 75mm2 or so, possibly more.

Er... me too. My stuff isn't 35mm at all... Knob. :ashamed:

shenion · Jun 20, 2008

Most bigger welders will have a table. Here's one from my Miller:

That's AWG cable sizes, you will have to convert to cm^2.

I have about 100 feet of 1/0 cable (0.3249" or 53.4mm^2). The wire is probably worth more than I paid for the welders

I'd go bigger than the table for MIG as you want the voltage more cinsistent.

Wozzaaah · Jun 20, 2008

Thanks Shenion, very helpful :hug:

.

Drains · Jun 20, 2008

simondrains said:
Someone with a brain in their head (Shenion, probably), will be able to calculate an "acceptable" voltage drop/length etc.

Told ya

Weldingartisan · Jun 26, 2008

Woody.v8 said:
I use 95mm on the dc 800 75mm on the synergic 500 and 50mm on the smaller stuff

95mm! You must have muscles on your muscles, wouldn't fancy coiling 50 metres of those leads up.

I use puny little 35mm2 - buy a 50metre roll and cut it in half, my plug top inverters work fine off that. W/A

shenion · Jun 26, 2008

Weldingartisan said:
95mm! You must have muscles on your muscles, wouldn't fancy coiling 50 metres of those leads up.

I use puny little 35mm2 - buy a 50metre roll and cut it in half, my plug top inverters work fine off that. W/A

I have some 75mm^2, but only 25' lengths.

I have a 400A Tweco MIG gun that came with the welders. Heavy cable and the gun is Bakelite. Probably 5+ pounds to hold it. I promptly found a 180A gun as the big one was heavy to hold and at about 17" long hard to get in tight places.

Would use #2 (35mm) if I bought more as most of what I do is light work and 25' will reach most of the garage.

My main leads are about 30' and I have two 20-25' extensions. Makes coiling them up easier and I can extend if needed.

gavuk · Jun 26, 2008

can someone enlighten me how do u measure 35mm 75and 95 mm cable ,as i said stores makes it easy for fitters 300amp or 600amp ,i really haven't got a clue how to measure/identify :ashamed:

Cable Length

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