Saturday Night Discrimination Quiz/Guess

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It's usually my trick, but this afternoon it was my neighbour's turn to 'hedge cut' the cable of his hedge cutter! He totally sliced the two core cable supplying the Class 2 tool, without any contact with the nearby earth.

It transpired that the power supply arrangement was 'interesting' .... an RCD-protected B32 MCB in his house CU fed a mini-CU in garage. A B16A RCBO (I know!) in that mini-CU supplied a double RCD socket (I know, again!) in the garage. He had a cable reel extension plugged into that, with a 10A fuse (don't ask me!) in its plug. His hedge cutter was plugged into that (in the middle of his lawn - again, I know!) with a BS 1361 plug/5A fuse.

So, which one(s) of that selection of protective devices do you think/guess had operated as a result of the fault?

Kind Regards, John
 
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'None' is very tempting! But since that's been taken, I'm split between the B16A RCBO and the B32 MCB ... bet I'm wrong!
 
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I have to say that the last time I did it (with RCD, B32 and some fuse in the plug) the answer was 'None' - but that was not the case today. I'll wait a little to see if anyone else wants to throw in their offering before revealing today's answer.

Kind Regards, John
 
With 2½ of you suggesting the B32 MCB, I wonder if any of you could indicate why you might expect that to operate and not the B16 RCBO?

Kind Regards, John
 
Well I was thinking that the B16 was more likely to operate than the B32... but by no means guaranteed
[I'll get off the fence and settle for the B16 then]
 
I've seen all sorts of odd happening where discrimination is concerned.

Including RCD's not tripping!
 
With 2½ of you suggesting the B32 MCB, I wonder if any of you could indicate why you might expect that to operate and not the B16 RCBO?
Kind Regards, John
I asked a friend and he just so happened to be your neighbour!
In an ideal situation, you would expect the 5A to go first, if no earth leakage.
But not always ideal, if you had offered the main fuse as an option, I may have opted for that, before consulting your neighbour that is. As the answer to the question would not be the logical one, my illogical train of thought with neighbourly guidance was the 32 Ampere.
 
I asked a friend and he just so happened to be your neighbour!
That's cheating :)
In an ideal situation, you would expect the 5A to go first, if no earth leakage.
Indeed one would.
But not always ideal, if you had offered the main fuse as an option, I may have opted for that, before consulting your neighbour that is. As the answer to the question would not be the logical one, my illogical train of thought with neighbourly guidance was the 32 Ampere.
Fair enough reasoning! However, if, by 'main fuse', you mean the cutout fuse, I would certainly accept that as an answer if you wish to opt for that one (I didn't mention it, but it was obvioulsy implicitly there!).

Kind Regards, John.
 
Right, we've had votes for most of the protective devices - so this is where I make it a bit harder for you all ... we are not looking for a single answer - more than one device operated!!

Kind Regards, John
 

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