Duel boiler stat

[martineire]

I was working on a firebird popular 90 oil boiler yesterday, its boiler stat and high limit stat is a duel stat located on the top of the boiler the power was on to the boiler i had the cover off the duel stat and i was checking with my multi meter for power across the live and neutral and live and earth on the stats and i had power 230v then i checked across the live on the high limit stat and earth and then the next thing the there was a small bang and a flash from the the tip of my lead on my multi meter and it melted the tip of my test lead, the RCD for the boiler tripped in the house . Can anyone explain to me how and why this happened and what did i do wrong The tip of the test lead is slightly melted and half way up it is slightly melted too, could it of being that when i had the test lead on the live i touched the test lead off of the stat also and it short circut. Thats why it is slightly melted on to spots?

 

[Boilerman2]

Either the leads were plugged into your multimeter AMPS connection, which if you the try to measure voltage L to N or L to E will go BANG! or the un-insulated part of your probe may have touched an metal earthed part of the stat as well as the live terminal which will also go BANG!

but don't worry if we're being honest, we have all don it at some time

 

[martineire]

Yep it was defo the un-insulated part of the probe also tipped off of the metal part of the stat when it was on the live terminal We live and learn