How they dream this up??

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According to the table I'm looking at the max for a 6A B type mcb is 5.82 ohms but I think that's 80% figure

 
7.28 for a B6. but he missed the K confusing things

IIRC, above 23K its not extraneous
there's lots of confused people around, our kid had her house rewired, lovely 10mm GY to gas and electric, both come in in plastic, work that out!

 
too many people dont understand why things are done. taught on their 5 day course that if its copper then its to be earthed with 10mm. no mention of when it doesnt need done or why its done in the first place so they just blindly follow earthing everything

but the same people would also not earth it if it came in as extraneous but all the pipework inside was plastic...

 
It's another one of those 'saves the arguments' things. I don't disagree with it as a standard 'just stick it in' type thing to some extent, as long as people know why they are doing it, which is probably rare these days.

I've nearly fallen out with plumbers trying to tell me their gas safe bloke will tell them it is wrong if it isn't in the meter box. Not my problem, tell them to read the regs or STFU.

 
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