current / voltage leakage

[tomato5]

i have installed a new switch and holder in my room lamp can you tell me what reasonably priced device can I buy which would help determine any leakage

i wanted to guard against that somebody might touch any part by which he/she could get an electric shock

is it more important to check for voltage leakage, or current leakage? which ever is the right one, what is it called to go buy from Home Depot

thank you very much

 

[Skogsgurra]

Decades ago, I would use a small neon indicator lamp and test if it glows when connected between exposed parts of the lamp/switch and ground.

Today, I would use an LED. No series resistor needed if you are going to test leakage. And you probably don't need to worry about half-wave conduction, either. But, if you want to do it correctly, you should use two LEDs in parallel and make sure they are at opposite polarities.

If a standard LED lights up, you have something like one milliamp of current. That is not lethal (need upwards of around 50 mA to kill someone) but it is not good either. There should be zero mA and hence dark LEDs. Anything else indicates a sloppy installation (metal parts not grounded) or a defect in some other way.

There's no such thing as a leakage voltage. It is leakage current you are looking for.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[ScottyUK]

The problem is usually addressed by sound design, the use of quality materials, and through competent manufacture.

Unless something is desperately wrong with your room light there is no reasonably priced instrument which will measure what you are trying to measure. An insulation tester ('megger') will find a gross failure but on a correctly working light I'd be surprised if you get a reading that is on the measuring scale, which means you are moving into the world of more exotic test equipment if you want a numercial value rather than pass / fail.

 

[itsmoked]

If you are in 120V land:

If you have a voltmeter set it to measure 120VAC

1) Using the grounded outlet of interest measure from the HOT (narrow prong) to the other prong (the neutral). You should see approximately 120Vac

2) Now measure from the narrow prong to the ground prong. Again you should measure 120Vac.

3) With the lamp (or device in question) plugged into the same outlet and turned OFF do the following.

Using the other half of the outlet repeat 1 and 2 above. This proves the meter, and the ground, and the leads, and the probes, are functioning.

The key here is once 2 above is achieved LEAVING THE PROBE STILL IN THE GROUND RECEPTACLE move the other probe to the case of what you want to check for 'leakage'.

If there is any chance of leakage you will measure a voltage.

You will have about 3 cases.
A) You measure 0 to 3V. Recheck to confirm.
B) You measure between 4V and about 55V.
C) You measure between 55V and 120V.

Case A) No problems.

Case B) There's a problem but it's probably only caused by capacitive or inductive coupling. Set your meter to 10 or more amps AC. Change the probes to measure AMPS. And check between the case of the test subject and the outlet ground probe. You should see almost no reading. If this is the case increase the meter sensitivity until you get a useful reading. Perhaps a few milliamps. Your test subject has a problem. Figure out what it is. It's a high impeadance (resistance) to the line voltage (hot). Possibly dying windings in a motor or compressor, or an open ground on an EMI filter, or very thin or wet insulation.

Case C) You probably have a real short to the case of the test subject. Possibly a lethal weapon is before you. OMG it's a weaponized lamp!! Unplug it and find the problem using your eyes and an ohmmeter.



IMPORTANT NOTES:

Once test three is complete with the device OFF repeat it with the device ON. All the same results apply.

If the device is non repairable cut off the cord and recycle the device or trash it. You don't want Johnny finding it and plugging it in.

The INSTANT you're done doing a current test reset the test leads back to voltage so you don't accidentally do a voltage measurement and blow the meter up.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[mcgyvr]

You could get a power strip with GFCI protection and just leave the lamp plugged into it.. Any short to ground would quickly trigger the outlet to shut off power. Just like in your bathroom/kitchen.

IF I was concerned about a repair I just made I would simply use a multimeter set to continuity mode (ohms w/beeper or similar) and test between all energized metallic components and the metallic body of the lamp..
Anything but an "open" (or any resistance measurement) would be a problem.

 

[Skogsgurra]

I need to explain that I am not the moron that I seem to be. I actually know how to use a DMM! And some other fancy equipment. But the OP actually asked for a "reasonably priced device" that would "help determine any leakage". He didn't ask for something to measure current (or voltage).

I know, you will still think that I haven't moved out of that cave. But I have! Yes, really! I even wear clothes and eat with a knife and fork...

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[IRstuff]

Under $4.50 might qualify as "reasonable"

http://www.ebay.com/itm/LCD-Display...514?pt=LH_DefaultDomain_0&hash=item3ce9f060d2

TTFN
faq731-376

Need help writing a question or understanding a reply? forum1529

Of course I can. I can do anything. I can do absolutely anything. I'm an expert!

 

[VEBill]

It's good to explore all the alternatives. One shouldn't look upon subsequent replies as rebuttals to the first response.


My response would be to question 'Why?' does one want to measure leakage current?

If the wiring was done incorrectly, then perhaps voltages should be checked before currents. Imagine if the newly-installed ground connector is mis-wired with a Hot conductor. There's a lot that could go wrong here (in the worst case).

 

[Skogsgurra]

Easy, VE. I agree that follow-ups are not to be seen as criticism. I fell into some sort of humorous mode to illustrate that I tried to answer the OP:s question verbatim. Thought you knew me better...

Still, leakage voltage doesn't exist. But, of course, a voltage that is caused by miswiring or that develops as a result of a leakage current does exist.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[tomato5]

Folks, I have never experienced such an outpouring of help. I really want to thank all of you
regards