Drilling through mains cable!

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no they aren't - nobody would know where to start looking
the Regs are (maybe) a deterrent
all that's (maybe) done is an insulation test which 'might' find a nail close to conductors and a loop test to confirm that circuits reach the consumer unit - a ring final test would be good.
I've seen testers walk around with hugely expensive multifunction testers confirming everything good without ever conducting basic tests like is a ring actually a ring
We were left with a sub circuit wired upside down (live neutral swapped) by a power company !
Don't trust anyone
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It's possible in an older house they simply re-used a notch made for either older cables or now redundant gas pipes etc. However, such a notch would normally be in the middle of a floorboard so it may still be nailed or screwed safely. If not, I'd put a steel strap across the notch *and* mark the floorboard clearly with the position of the cable.
--
*Beauty is in the eye of the beer holder...

Dave Plowman snipped-for-privacy@argonet.co.uk London SW 12
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Good idea Thanks.
London SW 12

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better for accessibility. Which is both a practical requirement (you did replace the floorboard nails with screws when you put them back down, didn't you? Makes lifting them next time *so* much easier; *and* gives you another opportunity to put a screw right through the cable you only just saw. Been there, done that, saw the flash, felt a total prat, still remember it though it was just about 20 years ago!) - and (breathlessly recovering back to the "both" where we started this sentence ;-) a requirement of the Regs when using junction boxen. I claim that under a screwed-down floorboard is accessible within the meaning of the Regs here, though I'll admit that it rather depends on the floor covering - vinyl you can peel back to reveal a nice hardboard with pipe and cable runs clearly labelled and access hatches is one end of the spectrum, while gert big sheets of marine ply, screed, and big-ass slate tiles would be quite the other ;-)

*was* normal practice, judging by the couple of older houses I've lived in and worked on, and comments in older installation guides. Except when I didn't, I usually played safe by putting any screws to replace lifted boards into, or pretty damn close to, the existing nail holes. These days notching's frowned upon, both because it weakens the joist, and because it makes it too unsportingly easy for Sod to guide your drill bit to them, as you discovered ;-) The current On-Site Guide says it's OK for cable to go *through* joists; holes a minimum of 5cm away from top and bottom surface, and (for structural reasons) close neither to the centre nor the edges of the span. It's also OK to run the cable in earthed steel conduit, which provides good mechanical protection; the conduit can go in notches in the top of joints, and again there's guidance on max depth of notches (no more than 1/8th the depth of the joist) and position (away from center of span, not right close up to edges either). As a third alternative, it says you can try to provide "protection sufficient to prevent penetration of the cable by nails, screws and the like", and immediately pooh-poohs its own suggestion by saying that it's "difficult to meet" that requirement for protection! Hunky steel plate (2-3mm thick or more) is sometimes fitted over existing joist notches as a nod towards this "mechanical protection" requirement, but by the time you've done the chiselling around the notch to install and secure such plates, you could probably have rerun the cable through holes deeper down the joists anyway.
Hope that helps, and glad to hear you got a proper job done on the damaged bit of cable...
cheers, Stefek
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his cables thro it rather than drill some small much safer ones
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In uk.d-i-y, Chris Oates <none> wrote:

Govt departments). Mr No Brains isn't going to be referring to any poncy On-Site Guide or other form of advice anyway...
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I still can't believe that after the initial flash you poked at it with a screwdriver A pal of mine drilled into an incoming main which (unlike yours) was un-fused - he lost huge areas of skin and had a long painful recovery - electricity is a killer ..not only for you as it can kill the person trying to save you,

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"Chris Oates" <none> wrote in message

I poked at it twice because in my panic to restore power the first time I did not make a note of which MCB had tripped. I used thick rubber gloves and an insulated elecrticians screw driver. I also knew the RCD would cut in again - not a great idea I admit but I was happy with the precautions.
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