Tig welder - overcurrent protection

[lodiinsparky]

A TIG welder needs 230 Volts and draws 54 Amps maximum in DC mode and 63 Amps max in AC mode (for welding aluminum). It is a single phase machine. The welder came with a 6 foot long power cord with attached NEMA 6-50P plug. The cord casing is embossed 8/3. Also included was a NEMA 6-50R receptacle. It would seem to me that the supplied power cord is too small, as are the the?male and female cord caps. I came up with 72.75 amps as the required rating for the over current, 115% of 63 amps 630-13. Is that correct or am I missing something. Thanks

 

[iwire]

Re: Tig welder - overcurrent protection

You did not mention duty cycle which leads me to believe you have not looked carefully at ARTICLE 630 Electric Welders.

Your probably all set, the manufacturer should know what it needs.

[ September 15, 2005, 08:57 PM: Message edited by: iwire ]

 

[lodiinsparky]

Re: Tig welder - overcurrent protection

Very intermitent use in a barn on a farm. I looked at 630 and was thinking that 630-31(a)(1) "... and 50% of the rated primary current for manually operated nonautomatic welders." So if you multiply 63 amps by .71 i come up with 44.73 amps I also transposed the 3 and the 1 in the original post. Sorry bout that.

 

[charlie b]

Re: Tig welder - overcurrent protection

Originally posted by lodiinsparky: Very intermittent (my emphasis) use in a barn on a farm.

It sounds like you are saying that you might use it today, and not again until next week. That is not the intended meaning of the phrase "duty cycle." That phrase is discussed in a FPN that follows 630.31(B).