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-   -   Funky voltage (at least to me) (http://www.diychatroom.com/f18/funky-voltage-least-me-178041/)

MickeyBee 04-24-2013 10:01 PM

Funky voltage (at least to me)
 
Was going to put in a GFCI today but decided to stop. Put the GFI tester into the existing outlet and it showed that every thing was wired fine. I then turned off the breaker and the tester showed the circuit was dead. Just to be safe I put a VOM across one outlet. The voltage started at 3V but went to 10V and then back to almost 0V within about 15 seconds. Anybody ever seen this before, and if so, how did you fix it?

gregzoll 04-24-2013 10:06 PM

It is normal for a gfci to do that, while the capacitors on the circuit board bleed of stored voltage. If you measured amps, you would have found that there was very little milliamps at that time.

I have come across some bad gfci outlets off the shelf, especially from Menard's hardware stores. I tend to stick with the Leviton Pro series, or Pass & Seymour Commercial series for my gfci outlets. Only way I found out one of ours was bad, when we did our bath remodel, was that the LED nightlight stayed lit after tripping the test button on the outlet.

MickeyBee 04-24-2013 10:11 PM

Thanks for replying to my question!

Maybe I was a bit unclear in my wording. The GFCI tester was used on a standard outlet to check that the wiring was correct. I never got to putting in the actual GFCI outlet because of that voltage issue.

gregzoll 04-24-2013 10:32 PM

What tester was it that you were using? I missed the part that you did not have it on a gfci outlet, but it would still stand, that the capacitors inside the tester even would hold a voltage, until it bleeds off. Remember that anything electronic, is going to have some form of capacitor, diode, resistor, etc. in it, so that it will work properly.

This is about the closes thing that I could find, that shows how small a capacitor on a circuit board is now. http://www.youtube.com/watch?v=bpFPTgYlM88

MickeyBee 04-24-2013 10:46 PM

The tester is made by AW Sperry Instruments. It can trip your GFCI and/or test for six conditions of your wiring such as:

open ground
open neutral
open hot
hot/ground reversed
hot/neutral reversed
correct

This tester showed that all was well, however, after removing that tool and checking the standard existing outlet with a VOM was when I noticed that strange voltage.

jbfan 04-25-2013 06:35 AM

Quote:

Originally Posted by gregzoll (Post 1166666)
It is normal for a gfci to do that, while the capacitors on the circuit board bleed of stored voltage. If you measured amps, you would have found that there was very little milliamps at that time.

I have come across some bad gfci outlets off the shelf, especially from Menard's hardware stores. I tend to stick with the Leviton Pro series, or Pass & Seymour Commercial series for my gfci outlets. Only way I found out one of ours was bad, when we did our bath remodel, was that the LED nightlight stayed lit after tripping the test button on the outlet.

Are you really going to stick with this story?:eek:

rjniles 04-25-2013 07:05 AM

More likely, phantom or induced voltage. Not a concern.

gregzoll 04-25-2013 07:51 AM

Quote:

Originally Posted by jbfan (Post 1166806)
Are you really going to stick with this story?:eek:

JBFan, take any device that has a capacitor in it. It takes time (seconds with a load attached), to bleed the voltage. Same happens with gfci outlets, when you trip them.

Take and plug in a LED nightlight, and you will see it still showing enough voltage to light the LED's, for about 20 to 30 sec's, before they go completely out, but the amperage is very very little, due to LED's only need milli-amps to help light them.

Basic electricity & electronics knowledge JBFan.

gregzoll 04-25-2013 07:52 AM

Quote:

Originally Posted by rjniles (Post 1166821)
More likely, phantom or induced voltage. Not a concern.

These testers would not show Phantom or induced voltage. No, it was just bleed off current on the capacitors in the device.

rjniles 04-25-2013 07:59 AM

Quote:

Originally Posted by gregzoll (Post 1166842)
These testers would not show Phantom or induced voltage. No, it was just bleed off current on the capacitors in the device.

In post #1 he said he used a VOM and measured small voltages. I still say phantom voltage.

gregzoll 04-25-2013 09:40 AM

Quote:

Originally Posted by rjniles (Post 1166847)
In post #1 he said he used a VOM and measured small voltages. I still say phantom voltage.

It would be if it stayed. It was just stored capacitance, that discharged, due to having the meter on the line.

Again, nothing to worry about, or as usual have some that want to turn these threads into pissing matches as usual.

ddawg16 04-25-2013 10:43 AM

If a high impedance meter is used to measure voltage on an unloaded line....the readings mean little if other ckts are active.

Because there is no load, any adjacent ckts can induce voltage on the ckt....the amount depending on proximity, how far the wires run adjacent and the load on the other ckt.

Any electronics on the now dead ckt would only induce a DC component on the line...not AC....but if the meter is a cheap one with a real low freq response, the discharge of something could be seen as an AC voltage.

One of the best ways to see if a ckt is dead....stick the wires to your tongue....or, plug in an incandescent lamp and then measure the voltage.

We used to have to install relays or resistors across an indicator light in remote panels. Induced voltage on the long runs was enough to turn on the light. If we were using something like a Sonalert, without the resistor or relay, you would hear it putting out a tone...

MickeyBee 04-25-2013 11:45 AM

Quote:

Originally Posted by ddawg16 (Post 1166949)
If a high impedance meter is used to measure voltage on an unloaded line....the readings mean little if other ckts are active.

Because there is no load, any adjacent ckts can induce voltage on the ckt....the amount depending on proximity, how far the wires run adjacent and the load on the other ckt...........

There is a CFL running about 12' away and it's sharing the same conduit but wouldn't the metal in the conduit absorb neutralize any fields?
(hope that's not a stupid question)

Not sure what degree of impedance my meter has but it's an IDEAL 61-360 if it helps.

Not quite ready for the tongue thing so I will be trying the incandescent idea. Is there a wattage range that would work the best in this situation?

Oh, and thanks guys! At least I am starting to feel a bit more comfortable about this issue.

ddawg16 04-25-2013 11:55 AM

If the wires are in the same conduit....makes no difference....

The 'tongue' thing was a joke......

A night light will be enough...as long as it's incandescent.

MickeyBee 04-25-2013 12:56 PM

Quote:

Originally Posted by ddawg16 (Post 1166991)
.....The 'tongue' thing was a joke.....

That was my first impression but then I thought that maybe you were one of those kids who grew up with a fetish for licking 9 volt batteries and that you were serious.

I still like the tongue tester idea and plan on inviting over a neighbor to do the testing because I don't think I have any incandescent bulbs left in the house.


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