How can I tell if these light switch wires are live

FrankFalcon

Oh, now I'm stumped.  I was going to buy BOTH of those items today given how cheap they are.  So, what is the solution? When professional electricians turn up at jobs where they have no knowledge of the wiring they must use something???  And also, may I ask...Suppose I go out and buy a professional circuit tester.  The box type with the 2 prongs.  Surely that bit of plastic/rubber insulation on the prong is not enough protection from getting a shock, or is it?

chrisw

I think you're being over cautious. Just turn off the main switch on the consumer unit and check nothing works. 

You probably have a greater risk of getting run over on the way to Screwfix than of getting electrocuted once you've switched the main power off.

forgotmyname

Proper testers will be rated for 500volts minimum and a lot will be safe for 1000volts+

You pull the fuse or breaker for that circuit then test for a voltage with a decent branded meter

before you touch anything.

I buy lots of cheap meters but I would not use them for mains testing even if they do state 600v CATIII.

Buy a decent branded tester and compare the thickness of the leads and quality of the insulation its

far better quality and less likely to harm you.

If they have doubts as to what is wired where they may cut the power to everything.  

mobileron

Small digital test meter about £10 in Amazon,onto you tube to show u how to use it.

RumRat

Just turn it off at the consumer unit......

Cornucopia

FrankFalcon said:

Oh, now I'm stumped.  I was going to buy BOTH of those items today given how cheap they are.  So, what is the solution? When professional electricians turn up at jobs where they have no knowledge of the wiring they must use something???  And also, may I ask...Suppose I go out and buy a professional circuit tester.  The box type with the 2 prongs.  Surely that bit of plastic/rubber insulation on the prong is not enough protection from getting a shock, or is it?

If you aren't confident in doing this work safely then please find someone who is.   

Part of that confidence will be understanding different types of test equipment, their features and limitations.   

It doesn't require a great deal of insulation in order to protect from domestic voltages, and some types of test equipment will be rated for much higher voltages than those.     Again, though, part of understanding the topic is an understanding of insulation.

Apodemus

FrankFalcon said:

So, in this situation...Flick wall switch up -Light illuminates.  Flick it down and light goes out  Is there any way the wire to that light can be live?  Sorry if this sounds obvious.

Not obvious at all...unless you are in the US. In UK, switches normally work the other way, except where the lights can be switched from two different locations - which is another reason for making sure you turn everything off at the mains (and not just the lighting circuits as someone may have wired some lights from a ring main).

Heedtheadvice

I agree with those posts advocating caution.

Ensuring domestic equipment is repairable does not mean we are all qualified or competent to do so! It is as much to do with parts availability and accessibility as a user fix!

Some services, (probably most services?) have "hidden" dangers and that there are regulations etc and is why professionals go through training, competency certification, use the right tools for the job etc (or at least they should do!) so that they work safely and complete a functioning and safe system left for the customer. We all know that there are cowboys and that proper job does not always happen.

For DIYers part of the best knowledge is knowing ones own level of competence -unlike it seems your previous householder! Questions asked often reveal levels of knowledge and therefore competence! Forum answers reveal to the knowledgeable incompetence to advise such as on this thread too! Anyone can post and a reader has no way of splitting good from bad suggestions and advice. (My post can be bad advice too but how do you know?)

Circuits are normally swtiched live....but can also be switched neutral...or a combination of the two!

Although it ought to be safe when you switch off at the consumer unit (making sure it really is off by testing and ensuring nobody else happens to switch it back on again whilst you work), you still have to ensure that you then do the works correctly in line with Standards etc. to ensure safety and correct function. Quite easy to change a fitting it might seem but when the wiring to it is in question it would be remiss to not ensure that it meets requirements.

Just call in a qualified electrician. It will cost more, other problems might be found or improvements to update the system, but how much do you value safety, your property or life?

forgotmyname

Not even a previous householder, when we moved into this property it was a new build.  Landing light uses 2 switches

one up and one down. I fitted an LED bulb and it glowed even with both switches off.

Standard bulb didn't show any light but the LED had enough power to light the LED and more than enough

to give more than a tingle.

Who knows if they switched the live or the neutral line?  We know what should be there but you cannot

trust anything.

FrankFalcon

I will do this at weekend.  I am going to take your advice and turn off the main power at the consumer box.  Going forward though I do want to SAFELY be able to use a test Meter.  Please can somebody suggest a safe meter for me to buy? Also, if I do buy a decent, branded meter am I correct in assuming I can use the prongs to test 240v without any danger?  Obviously, I wouldn't touch the prong metal.  I know I may be over cautious but better to be safe than sorry.