Why would a LAP Voltage Detector be showing live current in this situation?

[berks1234]

Hi,

I purchased a LAP non-contact voltage detector to check my sockets.

One of them is cracked and needs replacing. So I went to the Consumer unit and isolated the all of my circuits.

Then I went back to the broken socket and tested it again.

Everything appeared to be fine, and I removed the socket from the wall. But something told me to test it again. It was at that point the detector flashed and turned red.

I couldn't understand why. I tested it on another socket and the same thing happened again. This only happens if I put the probe into the live pin, or touch the live terminal.

It's not a continuous alarm, but it is still worrying. So I have left it until someone can help to explain what is going on.

 

[Darkwood]

Welcome to the forum

 

[Pete999]

Is this a non contact voltage tester?

 

[Octopus]

Welcome

You have just experienced why these "detectors" aren't to be trusted.

 

[berks1234]

Is this a non contact voltage tester?

Hi yes, and it cost me £7.

I also purchased a socket tester that plugs into the socket. That shows the socket to be isolated (not live).

But the detector pens beeps on and off, and scares the life out of me. Even though I have tripped all of the fuses from the Consumer unit.

Thanks

 

[berks1234]

Welcome

You have just experienced why these "detectors" aren't to be trusted.

What can I do?

 

[Pete999]

From Screwfix was it, I dare you to take it back and demand your money back, they ar very good for simple checks but a waste of money and dangerous for trying to prove if a circuit is dead or live. Either get your Electrician to prove and make safe, or get a proper voltage indicator to GS 38, either way don't use those things for safe isolation.

 

[tomspark93]

Although they have there uses they shouldn't be used to prove dead

 

[Wes1000]

Like pete999 said. Buy a proper voltage tester to GS38 and throw away sootie's magic wand.

 

[Pete999]

https://www.youtube.com/watch?v=kGHViQ5axKA

 

[berks1234]

From Screwfix was it, I dare you to take it back and demand your money back, they ar very good for simple checks but a waste of money and dangerous for trying to prove if a circuit is dead or live. Either get your Electrician to prove and make safe, or get a proper voltage indicator to GS 38, either way don't use those things for safe isolation.

Yes.

It works great for detecting. But it worrying for testing for dead voltage.

What is a good tester to GS38?

I have just passed my basic electrics course at College, but we didn't do any live safe isolation tests.

We just talked about it.

So I need some equipment recomendations.

Thanks

 

[DuaneMHunt1976]

GS38 is 4mm or less sticking out of the prob

http://www.NoLinkingToThis/p/kewtech-kt1780-s-ac-dc-voltage-tester/53370
some thing like that will do
(i did show a fluke a bit deaer, also didnt have its covers on so didnt show the GS38 bit)

 

[berks1234]

GS38 is 4mm or less sticking out of the prob

http://www.NoLinkingToThis/p/kewtech-kt1780-s-ac-dc-voltage-tester/53370
some thing like that will do
(i did show a fluke a bit deaer, also didnt have its covers on so didnt show the GS38 bit)

Hi, I know the name Fluke.

Most Electricians seem to have them.

I have just found this guide. It's quite good.


http://www.hse.gov.uk/pUbns/priced/gs38.pdf

It says 2mm is even better, but anything under 4mm. Looks like I am going to have to pay a bit more.

That Voltage pen is still good. At least it detects.


Thanks

 

[Richard Burns]

If you are using this for DIY use I would not go too expensive on the tester. A B C D E
2mm of probe is very hard to use on tight terminals and can give you a false reading if it has not made contact with the conductor.
As the guide says different probe tips can be more useful.
There are other voltage testers out there that do not have quite such good tips but are far cheaper (and the tips can be ground down if required) and still provide voltage testing and the same level of safety as the more expensive ones with more features.

Oh yes and the non contact testers can be set off by being hit, moved around, passed close to metal, pushed too fast against a surface, exposed to static.
Generally they are an indicator and can be very useful but are not reliable.

 

[PEG]

Yes.

It works great for detecting. But it worrying for testing for dead voltage.

What is a good tester to GS38?

I have just passed my basic electrics course at College, but we didn't do any live safe isolation tests.

We just talked about it.

So I need some equipment recomendations.

Thanks

Hi berks,i have a question, just what type of electrical course,did not teach the the very thing,which is at the beginning of every single electrical investigation?

I have taught this to every person i have ever instructed,even before i would ask them to wire up a plug-top.

Without this ability,every single wire you ever come across,could be that revolver in the Deer Hunter :dead:

 

[sparksburnout]

"iv'e just done my basic bricklaying course at college, but we didn't do anything about mixing gobbo. Any idea why this wall has collapsed??" Allah give me strength............. What did the other 3 berks say about it?

 

[berks1234]

Hi berks,i have a question, just what type of electrical course,did not teach the the very thing,which is at the beginning of every single electrical investigation?

I have taught this to every person i have ever instructed, even before i would ask them to wire up a plug-top.

Without this ability, every single wire you ever come across, could be that revolver in the Deer Hunter

Hi, the basic electrical course was a component to another course that we were doing, and they did teach us about safe isolation. But out of a book.

What I lack is the practical experience, and ideas about the best equipment to use.

This is why I purchased a voltage detector pen, and not something more accurate.

Thankfully I was fortunate enough to double check the outlet again after I had isolated the circuit from the Consumer Unit.
I only want to be competent with Domestic Electrics. So I am now thinking about doing a diploma in Electrics, and in the meantime purchasing an EAL Electrical Installation Course book.

Thanks

 

[TJ Anderson]

Hi, the basic electrical course was a component to another course that we were doing, and they did teach us about safe isolation. But out of a book.

What I lack is the practical experience, and ideas about the best equipment to use.

This is why I purchased a voltage detector pen, and not something more accurate.

Thankfully I was fortunate enough to double check the outlet again after I had isolated the circuit from the Consumer Unit.
I only want to be competent with Domestic Electrics. So I am now thinking about doing a diploma in Electrics, and in the meantime purchasing an EAL Electrical Installation Course book.

Thanks

You have done the right thing mate, you have identified something was amiss and when you were unsure, you sought more info.
Safe isolation is simple.
Basically it is prove, test, prove. There is also locking off, tagging etc but you won't be doing that at home.
A basic voltmeter is sufficient in your case.
1. Prove meter on a known supply. This is to prove it actually works.
2. Test what you have isolated between all conductors to confirm there is no voltage present.
3. Retest your meter on known supply. This is to prove it still works.

 

[sparksburnout]

You have done the right thing mate, you have identified something was amiss and when you were unsure, you sought more info.
Safe isolation is simple.
Basically it is prove, test, prove. There is also locking off, tagging etc but you won't be doing that at home.
A basic voltmeter is sufficient in your case.
1. Prove meter on a known supply. This is to prove it actually works.
2. Test what you have isolated between all conductors to confirm there is no voltage present.
3. Retest your meter on known supply. This is to prove it still works.

Is a basic voltmeter to GS38 then??

 

[Pete999]

Is a basic voltmeter to GS38 then??

An approved voltage indicator plus a proving unit is what you require, there is no compromise when isolating a LV system " not a basic voltmeter"

https://www.google.co.uk/search?q=s...t=firefox-b&gfe_rd=cr&ei=A8dKV8eLINfBaIySv8gG