oxford arc welder

[slowcoach]

Hi all, Need a bit of advice, I have been given an old Oxford arc welder and was wondering what type of mains supply cable would be suitable, and what amp breaker should I go for. At the moment its got a 3 pin plug on it, but I reckon if I weld at 100amps this 13amp fuse will blow 

I'm only thinking of welding upto 6mm plate with 6013 rods.

Cheers
Rob

[ieezitin]

Rob.

I cannot help you with the wiring problem but I can tell you that welder will work wonders for you, I had one thirty years ago and back then it was thirty years old, I remember having a job come through our shop where we had to fabricate 1-1/4” thick plate Motor gearbox pedestals for a local steel mill, I welded solid for two weeks with 6MM rod 7018 and didn’t phase the little green machine.

Enjoy your gift.               Anthony.

[John Rudd]

My arc welding set is good for 140 amps and has just a 13 amp fuse in the plug..Nothing special...

[slowcoach]

Thanks guys  , got it working off a 30amp breaker, wired to a industrial 32A plug and socket. Just got to make a trolley for it now  

Rob

[slowcoach]

Hi,

I tried welding at 100amps yesterday on the old oxford, but the house 32amp MCB breaker kept tripping  The fuse in the workshop did'nt trip (30amp) just the one in the house which supplies the workshop consumer unit, The house consumer unit is RCD, but the RCD does'nt trip just the 32amp MCB. I have 6mm cable going to a blue 240v 32amp plug and socket with suitable cabling to the welder (4 meters of 32amp cable). Do you think changing from a type B to a type C mcb will work?

Any help always appreciated 

Cheers
Rob

[lordedmond]

to throw a bit of light on the subject


that welder will work from a 13 amp socket provided that socket is on a ring main and fed with a 32 amp fuse,  note the word fuse not a mcb

a 32 amp fuse will take 32 all day and approx. 50amp for about one hour continuous ,  a 13 amp fuse will take approx. 20 for one hour


the point to note here is that a fuse will tolerate an overload for a time but an MCB will trip at just over the rated current , note that some MCB's are rated for transformer inrush ,but these are not normally found in a domestic enviroment

I know that welder will work with fuses as described because I used to own one , has yours got the 2.5 volt heating tappings ( I think they were tagged brazing or something )


From the above please note that MCB will give you better fault protection whereas fuse are not so good , just do the maths  a dead short across a 13 amp fuse  say 0.0001 ohms at 240 volt ( UK ) give an instantaneous current flow of 240 /0.0001 = 2,400,000 amps    think about it


Stuart

[SemiSkilled]

A  C type breaker will give you different tripping characteristics, they'll take inrush current better than a B type the only thing is to meet the reg's the loop impedance for the c type is a lot lower ie you'll need a good earth.

You may be able to test for this, a loop tester just plugs in push a button but youll need the loop tester

Easiest way out is a 32A RCBO a 32A mcb and an RCD in one device

http://www.google.co.uk/products/catalog?hl=en&xhr=t&q=32A+rcbo+c+type&cp=15&um=1&ie=UTF-8&cid=15305687735072198038&sa=X&ei=0gNoTZjrBsaWhQeJhYjtDg&sqi=2&ved=0CDYQ8wIwAg#

Lee