Power Off Before Corded Drilling? Impossible!

Tozzy · 27 Oct 2009

Hi there,

I've just bought myself a corded hammer drill because I was so fed up of taking so long to perform a simple drilling task with my cordless! Sometimes, I'd groan and attempt the task using 'no more nails' instead lol.

The problem is, the drill relies on a constant power supply, hence why it's called a corded drill (duh!), which means obviously, I can't turn off the mains power supply. Is it essential to turn off the power supply or is the drill safe to use with the power on? I was abroad once and a friend of mine who lives there let me borrow his corded drill and I said that if I turn off the mains power I won't be able to use it! He laughed and said that it didn't matter about leaving it left on! I didn't believe him and asked him to risk electricuting himself lol.

Any ideas would be greatly appreciated.

Johnmelad502 · 27 Oct 2009

If you turn off the power supply you can't use it so I think you have answered your own question.

Just don't drill through the power supply

Diyisfun · 27 Oct 2009

If you think that you may be drilling where there is wiring & assume you could with the power off, it could be possible to drill part way through a cable & not know & so have a potential problem.
If you have more that 1 circuit you can turn one off.
You can get a detector to check for cables in the wall.
A good cordless drill, is capable of drilling through stell/concrete etc.

Tozzy · 27 Oct 2009

If you think that you may be drilling where there is wiring & assume you could with the power off

I can't turn the power off because then i wont be able to use the drill.

You can get a detector to check for cables in the wall.

This is a good idea. Will look into this. Thanks.

Surely everyone has the same problem though? Anyone with a corded drill must have to turn off the power supply. You'd get electicuted surely? Or is the drill specially equipped to be used with power on? In the manual, says something about handle is equipped with rubber handles in the event that a cable is hit. I don't understand it to be honest.

I just don't want to start drilling and find I'm in danger.

AndrewDavie · 27 Oct 2009

Depends on what you are drilling for and where.
eg, if you are just putting up a picture hook, then I'd check for cables behind it and also locations vertically and horizontally for switches and sockets. If ok, then I'd be happy using a corded drill.
otoh, if you are actually working on any electrics, say replacing a surface box with a flush box, then you'd want to turn the power off.

If you were competent and doing a substantial amount of work, then in the interests of time, you could isolate just the circuits for that room and power the drill from another room/circuit, but be aware that that is more involved than just flicking the MCB off as it's still possible to get an Earth/Neutral fault in that scenario. (I've made that mistake a few times doing DIY and tripped the main RCD leaving me in the dark!)

Tozzy · 27 Oct 2009

Depends on what you are drilling for and where.

I'm only worried because I have to drill where there are lightswitches and plug sockets. Just putting up battens for a new kitchen carcass. I'm a complete novice where electrics are concerned. I haven't a clue where cables are likely to be or anything so wanted to ask. I'll buy myself one of those detector things. They're only about £8-£15 I think.

Thanks for your help guys

Diyisfun · 27 Oct 2009

Tozzy said:
Depends on what you are drilling for and where.

Click to expand...

I'm only worried because I have to drill where there are lightswitches and plug sockets. Just putting up battens for a new kitchen carcass. I'm a complete novice where electrics are concerned. I haven't a clue where cables are likely to be or anything so wanted to ask. I'll buy myself one of those detector things. They're only about £8-£15 I think.

Thanks for your help guys

Take care there could still be wires there.

stargazer · 27 Oct 2009

Tozzy said:
I haven't a clue where cables are likely to be or anything so wanted to ask.

They should be

(a) within 150 mm from the top of the wall or partition, or
(b) within 150 mm of an angle formed by two adjoining walls or partitions, or
(c) either horizontally or vertically, to the point, accessory or switchgear on the surface of the wall or partition, to which the cable is connected

So basically don’t drill along the imaginary lines formed vertically or horizontally from switches and sockets, or within 6 inches of the ceiling or a corner.

More info here

http://www.voltimum.co.uk/files/gb/attachments/niu/l/attachments/c5-43.pdf

There is no guarantee however that your installation does not have cables installed completely outside the expected areas, so as always safety first - use a wire detector.

Tozzy · 27 Oct 2009

Hi stargazer,

This is exactly what I needed to know. This helps a lot. Of course, I'll still buy a detctor. I've seen a Bosch one at £50. There ar cheaper ones but I want it to have max depth detection and will come in most handy for future work. Everything should be ok now then. There is also power switch for cooker too, but should show up on the detector.

Thanks everyone. Very speedy replies there and much appreciated.

bernardgreen · 27 Oct 2009

Unless it is an old metal cased drill the risk of severe electrical shock from hitting a live cable is not great but there is a risk. Minimise it by wearing gloves and keeping free hands away from any metal work or pipes.

You should wear safety googles when drilling a wall if there is any risk of hitting a cable or pipe. In most cases the fuse, MCB or RCD protecting the cable will react and remove power but there is a chance of a "roman candle" of molten metal being blown out of the hole before they react.

With pipes a jet of water with grit will come out and you don't want that in the eyes.

ban-all-sheds · 27 Oct 2009

But the corded/cordless Q is to some extent irrelevant - you should not drill holes in cables with either.

And yes, the Bosch DMF10 is good.

flameport · 27 Oct 2009

bernardgreen said:
You should wear safety googles when drilling a wall if there is any risk of hitting a cable or pipe.

You should wear eye protection regardless of what is in the wall. Splinters of brick, pieces of concrete, plaster or a broken drill bit will take out an eye very easily.

Tozzy · 28 Oct 2009

Hi all thanks. Btw, I don't want to go spending money if a cheaper model will do the job just as effectively so which model do you reckon I should buy? I think it depends on the depth of the wires etc. I mean it's just a normal wall (presumably 225mm?) on a semi detached house.

Problem with this first model is that there are no specs

Bosch £34.99 http://www.homebase.co.uk/webapp/wc...1&partNumber=277498&Trail=searchtext>DETECTOR

Bosch £49.99 http://www.homebase.co.uk/webapp/wc...1&partNumber=271938&Trail=searchtext>DETECTOR

Bosch £49.99 http://www.homebase.co.uk/webapp/wc...&partNumber=0073192&Trail=searchtext>DETECTOR

I will defo wears goggles

Aragorn84 · 28 Oct 2009

Well the image on the first link shows the model number of the unit, so surely you can look it up on the bosch website?

Tozzy · 28 Oct 2009

Aragorn84 said:
Well the image on the first link shows the model number of the unit, so surely you can look it up on the bosch website?

Of course, I didn't think of that! *feels silly* lol, thanks, I'll decide and then I'll buy something. Cheers for all advice.

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Power Off Before Corded Drilling? Impossible!

Johnmelad502

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