Duplex With 18V Reading...
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Phantom/inductive voltage usually found when using a high-impedance input digital meter on a switched outlet with no load attached.
Plug in a lamp and test again.
Either the reading will fall to -0- or the lamp will illuminate really dim if it's a true voltage.
Plug in a lamp and test again.
Either the reading will fall to -0- or the lamp will illuminate really dim if it's a true voltage.
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Someone trying to troubleshoot with something other than a solenoid tester.
Get one of these and save your self some aggravation.
Another post about loose or a failed connection and at a loss where to go next.. Get the right meter and start troubleshooting your connections... Draw the circuit out from the panel to the first, second, third and last device on it.. Go through them til you find the problem.. If there is only one device, then fix that one...
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If you use a low Z digital meter you'll be fine.
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Because you don't understand the magical properties of inductance.
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Put your meter leads on the conductors of a new bag of Romex, there will be voltage, set that Romex near a ballast or a bunch of home runs and there will be more voltage, but almost no current. Think about how a transformer works, when you run a conductor along side a conductor that is carrying current you have created a really crappy transformer.
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I make all the electrons line up for their Flu shots
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I told you that those are what electrotechnicians and security guards use. ECM feature writers also.I used this
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So you're saying this isn't used? Idk, I'm a first year so I'm asking
Digital meters have their place for their Cat safety ratings and the features they provide. For much basic trouble shooting or at the least testing for voltage, a wiggy type like that ideal or my favorite, Knopp tester will do nicely. When you need amperage, continuity, an exact voltage reading or other features, then you go to a multimeter, true rms. Some hardcore folks will also have an analog unit too.
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It is used but you have to learn to disregard certain readings.
Next time you have a 3 wire cable (black hot, red switch leg), read the red wire (with the switch off) and you will see like 15-20 volts.
I got called to a resi job one time where the electrician couldn't figure out what was "wrong" with the smoke detector circuit (showing 17V on the red interconnect wire) :laughing:
The digital meter is sometimes necessary but I do most basic troubleshooting with a solenoid tester.
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I make all the electrons line up for their Flu shots
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Knopps are rated to 1000 v now. I'm not going to test that out personally though, I believe em, but.........................:whistling2:
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Meter input impedance determines weather or not you will see ghost voltages or not. Back many years ago when I got started in this business we would use EICO, SIMPSON, or TRIPLETT analog meters. They had 20,000 Ohms per volt input impedance. What we would call LoZ today they would drag the voltage down so you could not read ghost / induced voltage. Fine for electricians not so fine for electronic technicians. Those meters would load electronic circuits down to the point where that they would not work properly.
At the same time the electronics techs would use a VTVM vacuum tube volt meter with a 11 megohm and I think some of them had a 22 megohm input. High input impedance grate for electronics techs not practical for electricians because they had to have 120 volts to operate and they had to have warm up time.
In the early 80's the Beckman's and Fluke's were coming on strong in the field and the and they had the high impedance input and the ghost / induced voltage became a problem for electricians. The ghost voltage has always been there it's just that we have always not have been able to read it.
The best meter to do simple troubleshooting with is the solenoid type voltage tester . After a wile you will be able to determine the difference between the real deal and induced voltage. It never hurts though to double check with a different type of voltage tester. I have to do it from time to time.
LC
At the same time the electronics techs would use a VTVM vacuum tube volt meter with a 11 megohm and I think some of them had a 22 megohm input. High input impedance grate for electronics techs not practical for electricians because they had to have 120 volts to operate and they had to have warm up time.
In the early 80's the Beckman's and Fluke's were coming on strong in the field and the and they had the high impedance input and the ghost / induced voltage became a problem for electricians. The ghost voltage has always been there it's just that we have always not have been able to read it.
The best meter to do simple troubleshooting with is the solenoid type voltage tester . After a wile you will be able to determine the difference between the real deal and induced voltage. It never hurts though to double check with a different type of voltage tester. I have to do it from time to time.
LC
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Anyone who's ever made the mistake of testing an open PLC input with a Wiggy has learned that each tool has an appropriate place.
I carry this in my bag with my 87V, it puts a resistance in parallel and helps narrow down suspected ghost voltages:
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Digital True RMS tester is all I use. I will never use a wiggy style tester again. If you learn how to use the tester properly it will be a invaluable tool.
Those wiggy testers may have been useful at one point in time, but today you have capacitors, resistors, inverters, inductors and all kinds of other funky stuff causing of electrical distortions on the line. While this maybe a headache for some who don't like reading all the extra garbage and trying to understand it, I've found it to be helpful in troubleshooting electrical problems. Especially in the so called "smarthomes" that use a butt load of capacitors and inductors for home automation.
But to answer your question, I'd like to think you have all the receptacles pigtailed. If you are testing a receptacle on the branch circuit and it should be reading 120v line to neutral, but instead you are reading something other as 30v or 15v or other, there could be a few possible causes.
One that comes to mind is a switched outlet. If the switch is off, the digital tester will pick up residual voltages floating around on the neutral causing inductance which registers impedance(Z) and wallah you have voltage.
A bad pigtail could cause readings like that.
You could help by providing more details. Letting us know the voltages from neutral to ground, neutral to hot, hot to ground and so on. You could also tell us if the receptacle is a dedicated circuit or a branch circuit. What type of wire was used, ie romex, mc, .... What else is turned on while you test. What is off.
While it may seem a little overkill, these are things you will have to consider when troubleshooting circuits.
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