Why does my spot welder keep tripping?

[mr_doggy]

Hi,

I have just purchased a second hand 240V spot welder. I am having great trouble trying to use it. Nearly every time I try to do a spot weld it trips the house.

I have it wired into a industrial socket (no fuse) which is wired into a 32 amp trip switch.

Are there any suggestions?

Cheers,
Richard

 

[Wozzaaah]

What does the data plate say about supply requirements? I've got a feeling spot welders need a pretty hefty supply.
What type is your mcb? If it's just a spare that you had then most likely it's B type.
C or D type is recommended for welders, they can handle the inrush current better.

 

[BillJ]

Trips the *whole* house or just the 32A breaker?
If the whole house it sounds like it might be tripping the RCD (residual current device) which would indicate an earth leakage fault. I would suspect a fault with the spot-welder or its wiring.

 

[mr_doggy]

Hi both,

Thanks for your replies. I'm not sure what type it is, i'll have a look when I am at home. It was originally used for a electric cooker that is no longer there.

It's the 32am breaker that's going rather than the whole house.

 

[mike os]

sounds like it draws more than 32a then.....

 

[mr_doggy]

Is that normal? It seems rather high to me?

 

[malcolm]

They do use a lot of current, but any that need much above 32 amps will tend to be 3 phase. Here's a typical 240V one that will run at 25 amps.

Which make and model do you have, and do you know what the max thicknesses are supposed to be? I would probably try a type C or D breaker. It's worth working out what value you'll need.

 

[madkayaker]

does it trip out instantly or when you try to spot weld? if you have a multimeter measure the resistance between L and N and that will allow you to work out the current. I=VxR

 

[madkayaker]

are you sure its 240V?

 

[Paul.]

It could well have a fault, but one of the things that a lot of people do with these small spot welders is to set the timer (power) too high, thinking more is better, usually they have a chart to tell you the settings for a given material thickness, based on the tip diameter and the length of the arms and the electrode force, a typical 1+1 weld will require only about 1/3rd to 1/2 a second, these things have a hefty power requirement, from 2kva at 50% power to 13kva or so flat out, so at higher settings, no chance off a 13 amp socket, my small one goes to 11 at max power. but I never use it above about 3/4 second or so, even on 1.5mm stainless,
Try turning it down and see if it still trips.
Here's a chart, yours may be different but it'll give an idea