Domestic circuit breaker board - welding machine ?

[skotl]

I've used aa mig , an arc welder and a 2.5 hp compressor and it hasn't tripped a 30 amp MCB , all obviously before I've read all this !
If you do it in daylight , none of your neighbours have their lights on and won't be aware of any dimming.....

A perfectly pragmatic approach, and I'm sure that's the case with 99% of home-welders.

 

[bernardgreen]

I've used aa mig , an arc welder and a 2.5 hp compressor and it hasn't tripped a 30 amp MCB , all obviously before I've read all this !
If you do it in daylight , none of your neighbours have their lights on and won't be aware of any dimming.....

The normal running current ( ie when the motor is at speed ) is not the problem. It is the short duration of high current while the motors are accelerating to speed or the short circuit current when the welding rod is touched to the work piece to create the arc. The duration of these high currents are not long enough to trip the delayed ( thermal ) mechanism in the MCB. They do however disturb the local supply network.

As to neighbours not seeing their lights dip. Some people do have lights on in daylight hours. The neighbours on the same phase will get voltage dips. Neighbours on the other two phases will suffer from overvoltage spikes and these overvoltage spikes may get reported as they can damage equipment and in some circumstances cause RCDs to trip

 

[DaveHerns]

We need someone to ask for permission to use a welder at home and see if it's granted .If yes, we can all apply .If not we'll keep welding in secret

 

[Norcon]

I have my own transformer (100amp supply) and no neighbours for a few mile. (they should be thankful)
Happy days. I'd be a real neighbour from hell and beyond if I ever had to live with others in close proximity.