Maybe the sudden current draw caused the mcb to fail before it could react ?
Perhaps the welder is faulty or requires a higher load mcb like a shower requires ?
It could also have been a poor connection and the load just melted the wire.
Garage consumer units are cheap enough to replace. I would be more concerned as to why the consumer unit the house it feeds from didn't trip it's rcd unless it is not on that circuit ?
Most likely a loose connection or possibly damp causing a corroded connection.
An MCB will react to overload before it gets to the situation described.
If the 2 wires are the ones going to the MCB they will be Phase and neutral no earth wire involved so the main house RCD won't trip.
saxo1
the garage is run from the house consumer unit Via a B32 mcb......this had not tripped.
as regards wiring loose, negative! all wires were well secured.
the point made about fitting a higher rated mcb, surely if this 32amp didnt trip then a higher rated one, say 40amp is even less likely to trip...wouldn't you think.
also the little welder is not wired into the garage circuit, it has a 13amp plug fitted... surely this 13amp fuse should blow before 2.5mm garage wire gets so hot it melts. your comments are appreciated and thought prevoking.
Who said anything about Phase and neutral going to one connection?
http://www.neweysonline.co.uk/schneider-mcb-type-b-10a-double-pole-240-440v-ac/1050076839/ProductInformation.raction
A double pole MCB has 2 terminals Phase and neutral so that all live conductors are isolated by the one switch.
You need to read what was said!
Shakes head !
Quote: Originally posted by saxo1 on 07/8/2014
Who said anything about Phase and neutral going to one connection?
http://www.neweysonline.co.uk/schneider-mcb-type-b-10a-double-pole-240-440v-ac/1050076839/ProductInformation.raction
A double pole MCB has 2 terminals Phase and neutral so that all live conductors are isolated by the one switch.
You need to read what was said!
Shakes head !