Discuss Odd request regarding phantom voltage! in the UK Electrical Forum area at ElectriciansForums.net

HappyHippyDad

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Afternoon all...

I would like to experience phantom voltage!! Is there any way I can reproduce it so that I can test it?

I know this might sound a little silly, and I realise my new Drummond test lamp would simply not light up if it is phantom voltage, but I would just like to see it for myself on something that I know for certain is phantom voltage.

I also want to test the digital and analog volt meter on it so I can see what they record.

Again... I know this sounds daft but I just want to see it for myself.

Cheers guys.
 
You can probably "see" this in your own home.

Locate a circuit, turn it off at the CU then attach your MFT - you will probably "see" the phantom voltage as long as the cable(s) run parallel to live circuit(s)
 
Not sure, haven't tried it, but if you took a nice length of three core and earth and wired it up to a load leaving the one middle core unconnected then you should get a "phantom voltage" on the unconnected core.
 
You'll get a much larger phantom voltage if you wire a simple circuit using two twin and earth cables. Put a plug on one end of each of them but only connect the live in one plug and the neutral in the other, leave the other conductor unconnected.

Phantom.jpg

If you use a nasty cheap multimeter which should have a ridiculously high input resistance you'll see a substantial phantom voltage between the unused conductors and earth.
 
Now thats exciting Marvo!

I'll let you know how it goes :smile5:
 
Posted a couple of times about an easy way of demonstrating this...Get a length/roll of t&e,expose conductors at each end. Connect L and N at one end. At other end,measure between cpc/N or cpc/known earth. By using differing test instruments,the results can demonstrate both the merits of individual instruments,and,the reason why readings can occur. Also,by adding "links",of varying impedance,between sections of the circuit,you can replicate what you would encounter on an installation,and greatly assist the understanding of results. As incredibly sad as it sounds,some of the most fun i had,as a teenager,was setting up such arrangements,on a large 8' x 4' board,with all manner of purloined items,and inventing faults and scenarios,to test and understand. I suppose a modern risk assessment of such an enterprise,would today prove "troublesome" :bobby:
 
I have to admit that in my 22 year naval career I have never found nor heard of phantom voltages to be a problem. We had 'Wibers' for voltage checking, a version of a drummond lamp, but they were few and far between onboard, and most of us had to rely on our fluke multimeters to check for voltages. (I am well aware they exist).

A far more dangerous problem I feel is the 2mm tip rule and shrouds. If I do not get a voltage and expect one, I have always usually expected it to be there and if not have a damn good check. Nowadays with 'shrouds' I inevitably get some non contacts, and I will investigate further. I wonder if a 'churned out' Electrical Trainee would immediately assume safely isolated. The so called safety of shrouded tips is possibly actually a danger.
 
I have to admit that in my 22 year naval career I have never found nor heard of phantom voltages to be a problem. We had 'Wibers' for voltage checking, a version of a drummond lamp, but they were few and far between onboard, and most of us had to rely on our fluke multimeters to check for voltages. (I am well aware they exist).

A far more dangerous problem I feel is the 2mm tip rule and shrouds. If I do not get a voltage and expect one, I have always usually expected it to be there and if not have a damn good check. Nowadays with 'shrouds' I inevitably get some non contacts, and I will investigate further. I wonder if a 'churned out' Electrical Trainee would immediately assume safely isolated. The so called safety of shrouded tips is possibly actually a danger.


Agreed.

take em off every time.

H&S gone mad
 
Obviously,the base line for these directives,are the lowest common denominator,but 2mm will not prevent someone without training and experience,from doing harm/damage. I have the same regard for safety catches on shotguns...i have NEVER,nor would i ever,use one. If you have to rely on that sliver of metal,that may or may not function,to prevent a gun going off when it should not,you do NOT know your job. It is the faith in these devices,that kids people in to believing, basic training can be skipped. Or...i suppose we could ignore the safe distance from the car in front,and just pop a neck-brace on every time we venture out...:conehead:
 
Obviously,the base line for these directives,are the lowest common denominator,but 2mm will not prevent someone without training and experience,from doing harm/damage. I have the same regard for safety catches on shotguns...i have NEVER,nor would i ever,use one. If you have to rely on that sliver of metal,that may or may not function,to prevent a gun going off when it should not,you do NOT know your job. It is the faith in these devices,that kids people in to believing, basic training can be skipped. Or...i suppose we could ignore the safe distance from the car in front,and just pop a neck-brace on every time we venture out...:conehead:

Just to contradict myself, I do remember live testing a faulty SFC using a meter with lengthy probes. The ship bucked, I slipped, and next thing I was snapping the tip off my now welded probe. So I can see the point in certain situations, and having shrouds on where necessary is a good thing. But I think relatively untrained personnel are far too likely to take a negative reading as fact when having the shrouds on permanently.
 
Just to contradict myself, I do remember live testing a faulty SFC using a meter with lengthy probes. The ship bucked, I slipped, and next thing I was snapping the tip off my now welded probe. So I can see the point in certain situations, and having shrouds on where necessary is a good thing. But I think relatively untrained personnel are far too likely to take a negative reading as fact when having the shrouds on permanently.
The EXACT same thing,happened to me.........only i was trying to get some tomato soup out of a flask,out at Wolf rock...:icon12:
 

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