Breaker tripping, wire diameter

[nickm85]

Hey,

I've recently picked up a Sip 130A Mig welder and its constantly tripping the 16A type B mcb in the house.

The garage does have a consumer unit but its a much older type with 15a wire fuses, which is holding up fine.

My plan is to upgrade the 16a mcb with a 20a type D (which apparently are good for welders).

My question is about the wire running between house - garage. What is the minimum diameter that will support 20a. Ive given it a quick measure and each strand including the sheath its exactly 4mm. I cant see any marking on the wire.

Thanks!

 

[Robotstar5]

Technically a 2.5mm² cable will carry 20A but it does depend on how & where it is run also the length of run. Why not just the replace the 16A B with a D rated mcb?

 

[nickm85]

I could, although for some reason I thought that 16A wasn't enough for 130A MIG?

 

[Robotstar5]

I could, although for some reason I thought that 16A wasn't enough for 130A MIG?

A 130A mig will usually run quite happily on a 13A plug so a 16A supply would be adequate, a 'D' curve mcb will take a higher initial current for longer.
Are you sure you have no other problems with the welder?

 

[madkayaker]

its not as simple as putting in a bigger and higher type breaker. what is the supply type, cable run and earth loop impedance valves? with out this information is is imposable to say if the changes will be safe as the current required to trip a C or D type MCB in the time required so that it hurts instead of killing some one is significantly higher.

 

[Pete.]

You could simply try swapping the breaker for a similar one, once you have confirmed that your wiring isn't causing too great a drop. Breakers do go 'soft' sometimes especially if they have been tripped numerous times or used as switches.

 

[Drains]

A 130A mig will usually run quite happily on a 13A plug so a 16A supply would be adequate, a 'D' curve mcb will take a higher initial current for longer.
Are you sure you have no other problems with the welder?

This is my first instinct. Can you check the welder on a different circuit, with no extension lead? No way should that welder be tripping a 13A circuit.

The other thing though - if it's a breaker in the house, is anything else drawing power through that breaker at the same time?

 

[madkayaker]

sometimes transformers can nucence trip breakers. a purfect example is a 3.3KVA 110
v transformers. the full run current is 10.6A si it has a 13A fuse in the plug but sometimes will trip a 32A MCB. just due to start up inrush. was testing a suspect transformer saturday (5.5KVA) and that had a 100A inrush (should have saved the screen grab from the tester)

 

[brightspark]

the 2.5kva transformer i have takes the 30a mcb out nearly every time as does the 180amp oilcooled welder just plugging it in one o these days il change the breaker

 

[hareng]

I was having similar problems mig tripping MCB B type even on lowest setting around 30A.

I now have a dedicated 32A supply fed from consumer box with C type MCB mainly to run a 3ph set at 400V 7.5KW inverter. Except it now throws the RCCD occasionally on lathe motor startup.
Use this feed to supply the mig, so far no tripping.