the charred remains

[SparkyTris]

I was trying to work out what precisely had gone wrong here. the problem was caused by fresh water running down a conduit and into the box.
seems surprising that the RCBOs did not prevent the whole thing from cooking up in the fashion that it clearly has.

 

[flameport]

Internal parts of the RCBOs remain live even when switched off.
They only disconnect the outgoing circuit wiring.

 

[SparkyTris]

of course yes, didnt think it through. obvious. thanks.

 

[SparkyTris]

Why would this box have been configured in this fashion? It is the distribution point for lights & and a couple of sockets in a modern steelframe GP farm shed. it is supplied via a DP isolator & SWA submain from the main dwelling house. Not too sure about main supply arrangement but almost certainly TNCS/PME like the rest of us in the area.