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.

 

[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

 

[Jurassic Sparks]

I use one of those volt pens purchased from my local wholesaler, it`s useful when checking switches ordination,
however it can pick up readings from roof insulation nylon carpets
stocking and suspendesr ( yes honest)
and recently it detected a copper pipe was live in the attic, turned out to be induction from its proximity to cables, although to be fair it was not yet bonded as we were using a temporary supply

 

[Leesparkykent]

The most reliable non contact voltage indicator I've found is the Martindale TEK100. For some reason I don't Know why but is the only one allowed when working on network rail contracts.

 

[TJ Anderson]

Is a basic voltmeter to GS38 then??

No it isn't, but a DIY'er is not going to have one in reality and it would be far more reliable than a volt stick. I obviously have an AVI myself.

 

[Pete999]

No it isn't, but a DIY'er is not going to have one in reality and it would be far more reliable than a volt stick. I obviously have an AVI myself.

The OP isn't a DIYer he is a builder, or so his profile says, consequently he should know better, a DIYer shouldn't be messing with safe isolation procedure, he should perhaps get someone in who is aware of the dangers, and knows how to isolate safely.

 

[TJ Anderson]

To be honest Pete, I wouldn't say a builder outranks a DIY'er when it comes to electrical know how.

 

[Pete999]

To be honest Pete, I wouldn't say a builder outranks a DIY'er when it comes to electrical know how.

Yes you maybe right there TJ.

 

[sparksburnout]

No it isn't, but a DIY'er is not going to have one in reality and it would be far more reliable than a volt stick. I obviously have an AVI myself.

I find this a very difficult situation to be honest. One argument would be that this OP obviously does not have much experience and should not be mucking about with electricity. But as you have said at least he did the right thing when he became suspicious of the non-contact tester. If we are going to stop people from "dabbling" with DIY stuff where would it end? We could adopt a (possibly European) sort of attitude that nobody is allowed to touch anything that they are not trained and competent to do. This could be anything to do with renovations to your house, or as a good example DIY car maintenance. I have just replaced the steering rack and track rod ends (along with a heap of other stuff) on my daughters car, but who knows exactly what I have done or what qualifications I have (other than common sense) to do it? The fact is I have been doing it for the last 40 years, but the MOT tester does not know if some numpty has fitted a track rod end onto half a turn of rod and that it could come adrift at any time and end up killing a bus queue full of people. Where do we draw the line? You can't even climb up a ladder these days as it is supposedly too dangerous, so by that yardstick this OP should not be going anywhere near his house electrics. Is it the nanny state? Are we becoming like a load of kids who aren't allowed to climb trees? Have I had too much home brew again???

 

[sparksburnout]

To be honest Pete, I wouldn't say a builder outranks a DIY'er when it comes to electrical know how.

I think it is the other way around judging from the builders round here.

 

[TJ Anderson]

I find this a very difficult situation to be honest. One argument would be that this OP obviously does not have much experience and should not be mucking about with electricity. But as you have said at least he did the right thing when he became suspicious of the non-contact tester. If we are going to stop people from "dabbling" with DIY stuff where would it end? We could adopt a (possibly European) sort of attitude that nobody is allowed to touch anything that they are not trained and competent to do. This could be anything to do with renovations to your house, or as a good example DIY car maintenance. I have just replaced the steering rack and track rod ends (along with a heap of other stuff) on my daughters car, but who knows exactly what I have done or what qualifications I have (other than common sense) to do it? The fact is I have been doing it for the last 40 years, but the MOT tester does not know if some numpty has fitted a track rod end onto half a turn of rod and that it could come adrift at any time and end up killing a bus queue full of people. Where do we draw the line? You can't even climb up a ladder these days as it is supposedly too dangerous, so by that yardstick this OP should not be going anywhere near his house electrics. Is it the nanny state? Are we becoming like a load of kids who aren't allowed to climb trees? Have I had too much home brew again???

There are some very good points there particularly with reference to car maintenance and most of us do that to some degree and don't expect to be berated by a qualified car mechanic for not using a torque wrench on our wheels nuts.

On here sometimes, you can almost find myself not answering someone with a helpful answer because it could appear to others that is what I would do professionally when all you trying to do is help someone to do the best they can with what they have available as non-electricians. Bear in mind they are very likely going to do it anyway even without advice. They are adults with free choice and reasoning at the end of the day.

 

[PEG]

This subject of "is a little knowledge dangerous?" ,is indeed,a contentious one.

When it comes to correctly and safely,identifying whether a circuit is dead,whether you are a dedicated DIYer,or builder,or otherwise,i feel it is too easy to do it right.

The equipment,specified for this task,is cheaper than the family visit to McDonalds.

The method of testing is very simple to learn,if you have any aptitude at all. How am i sure? Because my eight year old can use one,including understanding basic continuity,and its' DC scale.

So,my view on this,is if you are going to get "involved" with electric,in any capacity,is, spend the money,learn the function.

Or,leave it to someone who has,or will.