Electric Arc Welder Question ?

hi there chaps
just a quick question that I think I know the answer to, but need re-assuring
I have an electric arc welder 45-100amp
and both the earth cable and the gun cable has got rather tatty and to be honest is a bit too short for me , so I need to replace it
Question is does the cable I replace it with have to be capable of carrying at least 100amps ?
I have been to a electrical shop today to check it out but the thickness of 100amp cable is 75mm the stuff originally on the machine is a lot thinner than that any help would be welcome .
de Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I don't know what the stuff at the electric shop is, but you need to ask if they have any welding cable. Neoprene covered flexible cable. Most buzz boxes that go up to 225 amps come with number 4 AWG cable. So you ought to be able to get by with something a bit lighter. But I don't think I have ever seen any number 6 welding cable.
You might also try at your local welding supply. And also at your local scrap yard. I find welding cable at the local scrap yard fairly often. Most of it is bigger than number 4, a lot of it is 00. The bigger cable has lower numbers , so number 2 is bigger than 4, and 0 is bigger than 2 and double 0 is bigger yet. But even 00 is less than 25 mm in diameter.
That just made me think. Is your 75 mm measurement the circumference?
Dan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
circumference? ^^^^^^^^^^^^^ I agree. 75 mm is about 3", which ought to carry enough current to run a small city.
When you say the cables are "tatty," do you mean the insulation is worn and cracked? You should remember that the "ground" (return) cable doesn't need insulation. So, if that's the problem, why not just splice the two cables together, and use that for your ground? That will solve the *too short* problem, also. Then, replace the "hot" cable with a longer one of the same diameter as the existing one. If the present cables are working fine, why go larger? The down side of larger cables is cost, weight and loss of flexibility.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

There's no such thing as "100A cable". How it's rated is to look at the cross-section, then calculate the temperature rise for different currents, with the cable exposed or buried, used continuously or intermittently. Now (from rusty memory) the supply tails for 100A are something like 25mm^2, which is a worst case. With a welder though, especially for hobby use, you run current through it so rarely that you can allow quite some heat buildup with this intermittent use. So a much smaller cable can be used for "100A welding", although it might only be rated at 30A if supplying a house continuously.
You also need an extra flexible cable for welding use. I suggest you leave the electrical shop alone and go to a welding shop. They'll have the flexibility you need, and the ratings will be more relevant to how you're using it. You may only need a cable that's rated for 80A industrial welding
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Andy Dingley wrote:

Go to ebay and search for welding cable. You'll find just what you need.
John
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
How LONG are these welding leads? For a welder that tops out at 100 amps, I would think that #4 welding cable would do fine. As is suggested later, using both existing cables spliced together to form an earth cable should work. Welding cable cannot be used (per code) for electrical service, so be sure to ask for it.
I run 75' of #2 for an earth cable and 75' of #2 for the gun cable with 10' of #4 on the end to reduce weight and increase flexibility on a 200 amp machine that is seldom used above 130 amps DC.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.