Welding cable AWG selection

By - Date 10-20-2000 20:39

When determining the AWG size of arc welding cable needed:
1-Do you use just the distance from the welder to the electrode?
2-Or do you use the total distance from welder to electrode plus ground back to welder?
3-I have heard that most welders do not have circuits larger than 100V, is this true?
4-Some welding cable manufacturers talk about "open-circuit" voltage; is this the total circuit from welder to electrode to ground and back to the the welder?

By RonG

Date 10-21-2000 17:46

1-What kind of welding machine you got in mind?

2-Its a one way trip (you need to be concerned with how many Amps you can get through your cable)

3-Yes. Secondary voltage is less than 100V (hope you dont need much more than 30V)

4-Open-circut" generaly refers to GMAW (Mig) but you wont find many Mig guns longer than 25 feet.

By 357max

Date 02-06-2001 16:43

1. The welding distributor's cable charts show a complete circuit. Think of it as house wiring, the complete distance out to the receptacle back to the fuse/disconnect box. So, with welding circuits it is from one output stud/connection to the other. Notice that most cable charts show a size based on 4 volts or less drop. Consider this for SMAW or stick welding. Increase cable size with the same amperage when using GMAW or MIG welding. You do not want a voltage drop when MIG welding.
To check if there is a voltage drop just check the Open Circuit Voltage at the machine studs and then at the end of the cables. Be safe when doing this. Make voltage meter connections before turning machine on. Turn machine off before disconnecting the meter leads.
Open Circuit Voltage (OCV) is the voltage measured at the output studs/terminals with the machine turned on with no welding being done.
When welding is being done, the voltage measured at the output studs/terminals is called Load Voltage.
When welding is being done the voltage measured at the welding electrode holder, gun or torch (nearest the arc) is called Arc Voltage. This Arc Voltage is compared to the Load Voltage. For MIG welding there should be no difference. SMAW (stick) can tolerate the 4 volt loss or drop.
Remember, Stick welding machines, the amperage or current is set or controlled and the voltage fluctuates to maintain that "constant current/amperage".
MIG welding machines the voltage is set or controlled "constant voltage" type machines and the amperage/current fluctuates
with the wire fed into the arc.