voltage detectors

[saintjanet]

How reliable are these testers,the reason i ask is that we have just decorated the hall and on one wall we used to have a mirror and a couple of pictures.

At the bottom of this wall is the box containing the electricity meter, never having used a tester before my husband decided to buy one as we planned to put some other bits up in various parts of the house, however returning to the wall requiring the mirror the tester bleeps and lights up wherever you put it on this wall. Does this mean that the wall is completely full of wires or are we being confused by readings coming from the meter itself.

The meter cupboard is about 2ft 6ins high and the wall goes up to the hall ceiling and it bleeps and flashes at the top and sides and all the way down,so i am terrified of knocking any picture hooks into it or drilling any holes.

Any advise would be gratefully accepted.

Thanks,

Janet

 

[Steve]

cables should run in safe zones.

safe zones run horizontally and vertically from any electrical accessory including the consumer unit or fuse box.

However, there is no guarantee that previous people have gone in safe zones.

Look in your meter cupboard, can you see where all the wires go? There will be about 10-15 cables (or more) disappearing off somewhere. Some may go down. Take a photo and upload it here if you wish, we may be able to help.

 

[ericmark]

There are many cable detectors some look for just metal, some look for radiated power from 50hz and some use injectors and can trace a single cable and even identify where a break is.

I would not trust a volt stick too much although the type with both magnetic and electric combined are slightly better. The type which allow you to zero are a little better but still relies on correct settings and metal capping can shield the cable from radiating and many also have a metal detector function.

The "CAT" generator and receivers are very good and can trace cables buried over 3 foot deep in the ground.

At one time it was common with consumer units to run the cables in the cavity and they may not follow the safe zones when so deep. But because of the cavity wall insulation being used now that practice has stopped.

Electricians who use the gear every day get to know how good or bad their own unit is but with many relying on reed switches one knock can change how good or bad they are. So even if we know make and model we can't really advise on how good yours is.

The only way is to test it on known cables feeding light switches etc. However with the new Ali-tube cable it is likely they will still fail to find it. OK if you do put a nail through Ali-tube cable it will operate the safety device (fuse etc) but you would still have to renew cable.

Long live the picture rail!

 

[saintjanet]

Thanks for the replys, our knowledge of electricity is very basic. Looking inside the meter box the cables seem to go out to the left hand side into the outside wall and upwards. Although this small part of the wall gets no reaction from the voltage detector. I cant show a picture as my camera is out on loan.

The detector we are using is only a £9.99 Challenge 3-in-1 metal voltage & stud detector from Argos.

In the past we have knocked dozens of holes in various rooms in the house without any problems, obviously keeping away from electric light switches and plug points, this is why we thought the meter itself may be giving false readings, sorry but again the technicalities go a bit over my head as I work in an office, LOL

Janet

 

[sparkyspike]

The detector we are using is only a £9.99 Challenge 3-in-1 metal voltage & stud detector from Argos.

I don't think these are very reliable. I've never found one that worked anyway!

One way to find out if there is a cable is to firstly only look in 'safe zones' as mentioned. Then, use a strong insulated screwdriver and bore a hole slowly by twisting left and right. You'll feel instantly if you hit the sheath of a cable. You would have to push quite hard to pierce the sheath and then the cores. And you can use a torch to check your progress.

 

[ericmark]

The tester is designed to find a cable. Not a bunch of cables. PDF instructions here and for £9.99 in Argos what do you expect.

These cost around £400 and even This has some form of adjustment so you can set how sensitive it is. You need to consider the Permitted Zones are no go areas and use your meter on other areas just in case there is a pipe or wire.

 

[saintjanet]

Thanks again for all the information,it all makes more sense than it did before i asked.

 

[earlkitchener]

Most of these testers are very sensitive to static, you'll probably find if you hold the tester in one hand while keeping the other hand in contact with the wall fairly close by you will get sensible readings