Spot welder socket requirements.

[EastPete]

Picture now attached

Pete

[p2roverman]

My place was rewired from 2006 when the 16th edition regs were still in force. The split load consumer unit has a few of the circuits not through a main RCD and it is one of these circuits which I use for the garage where some of the equipment is, shall we say, sensitive. The 16mm (I think) cable runs off a 50amp MCB

[macafee2]

Originally Posted by EastPete

Thanks for all the responses folks- sorry for the delay in replying, I have been busy with other things over the last few days.

The cable to the garage looks fairly chunky (see picture) and runs for about 20 metres from the consumer unit/fusebox to the fusebox in the garage. The MCB on the garage 'spur' at the consumer unit is rated at 20A. The garage fusebox has four fuses - 2 rated at 5 A (lighting circuits) and 2 rated at 15A that feed the sockets in the garage through 2.5mm cables.
The welder seems to be rated at 25A for a 220/240v supply, with the short circuit (welding ?) current stated as 7000 A on the plate on the machine.

My mechanic at the local garage has borrowed the spot welder at the moment to put some sills on a Triumph TR6 - he says he could make me up an extension lead to run it of my cooker socket in the kitchen.

Can I change the MCB in the consumer unit to one rated at 30A, or will this be dangerous if the wiring to the garage is not up to the task ?

Cheers

Pete

I think you will need to know what size cable goes to the garage before you can know if uprating the fusebox mcb will allow damage to the garage cable when using the welder.

If using an extension lead you will need to consider the distance from socket to welder and cater for that. The longer the run, the thicker the cable I think.


Is running a new supply to the garage out of the question? I had to run a new supply so I could run my compressor, 2 X 3hp motors

macafee2

[HarryM1BYT]

Originally Posted by macafee2

are you sure it is an RCD as RCD's don't trip on overload but an MCB does.

macafee2

An RCD will be fitted with a button marked 'test', an MCB will not.


The electric welder in my garage fitted on a 16amp MCB, with a master RCD protecting the entire garage circuits, sometimes trips the MCB. It plugs in via a 13amp plug. The trip happens usually when I first strike the electrode, the surge. I have never had the 13amp fuse blow. It trips so infrequently, I just reset the MCB and carry on.



It really ought to be on a 16amp socket with a C rated MCB.


If the RCD is tripping, that indicates the welder has some leakage to earth.