Non-Contact Volt Detectors

[Wicksygas]

Some colleagues say they are invaluable and some not worth owning at all. What are the problems that people find with these? I feel that If you are aware of the limitations and you use them as they are designed the surely they are worth possessing.
Finally if you are a user, which model is the best?

 

[securespark]

I find them invaluable for checking, for example, an appliance casing or metalclad accessory is not live before you touch it.

I like the ones that vibrate as well as light up.

[And volt sticks that do that as well are a bonus!]

 

[RF Lighting]

I personally find it quite a handy tool to own, and are great for fault finding and circuit tracing.

The problem is they are not reliable, and have a habit of not always lighting up when testing a live wire. The will also not detect voltage through earthed metal so will not work on SWA, MICC, FP200, SY flex etc...

You must never rely on one of these testers to test that a circuit is dead. This must only be done with a proper voltage tester such as a multi meter.

I personally own a fluke volt stick, but AFAIK it has now been superseeded by a much bulkier new model.

 

[securespark]

We have been given these now, in preference to a two pole voltage tester:

http://www.idealindustries.co.uk/index.cfm?pid=15&op=dsp&pk=11744&fk=314

They have a button on the front: press it & it acts like a volt stick.

 

[breezer]

rub it on your jumper and see what happens

 

[Spark123]

They are very usefull for fixing mains xmas tree lights!!
Wouldn't trust them enough to test for dead though.

 

[Jim2287]

I like the ones that vibrate as well as light up.

bet u do


i use mine alot, mines a fluke volt alert

useful as initial check to see if you switched correct breaker off etc, but wouldnt trust it as definate ... like others said use multimeter or something to ensure its dead

 

[nozspark]

I got a job doing some main bonding because a gas man used one of these to test for earthed pipework, what he didn't take into account was the bell transformer in the same cupboard!!!

 

[Wicksygas]

Thanks guys, does anyone know why they are sometimes unreliable? Is it to do with different voltages or some other factors?
But like you say, it shouldn’t replace safe isolation.

 

[THRIPSTER]

Wicksygas,

I agree. Knowing how these devices work helps and getting to know your own particular model. Typically, testing on one side of a live mains flex will indicate nothing whilst on the other side will show 'live' - it is what you'd expect (Fluke volt stick) being nearer to the neutral and then phase cables respectively. Then you get onto the stranger indications as alluded to previously; however, these will depend upon the model and you need to understand how your particular model detects the fields before attempting to interpret what is going on. For example, a 'live' indication on a light switch face plate could indicate (i) The switch fascia is live wrt earth (ii) The switch fascia has an electrostatically or inductively induced voltage upon it wrt earth (iii) That there is a live cable adjacent to the switch plate that is giving this reading and throwing you off the scent. Knowing that a volt stick does not place a load on the source of voltage helps you interpret the reading.

 

[Wicksygas]

Thank you THRIPSTER,
Very helpful.