Voltage on switch leg. Switch off.

[gaelectric]

I had an inspector come out to a house and met with one of my guys on a final.

He plugged into a 1/2 switched outlet (switch in off position) with a real fancy Ideal arc fault/GFI tester. The neon lights on the tester glowed dimly and he made the statement that there seemed to be voltage on the neutral. The regular GB outlet tester had no lights glowing at all.

I went back to the house with my guy and we started checking out the circuit. We put the digital meter across the switch leg and the neutral and across the switch leg to ground and got about 40 volts. We went through the whole house checking the same way and found this to be true on every 1/2 switched outlet.

We took a piece of 14/3 NMB about 20' long and hooked the black and white to 120 volts and what do you know? The red wire had about 40 volts on it.

The last couple of days we've been checking every 1/2 switch that we ran across just to see. It always has about 40 volts on the switch leg with the switch off.

As this does not seem to be due to any sort of wiring defect such as too tight on the stapling or a tab on the receptacle not cut all the way I'm assuming that the red wire gets partially energized by induction or something. I'm no engineer. Just a guess.

There is no real potential present as you can touch the wire to the ground or neutral and there is no indication of a spark or anything.

I was looking for some input from others who may have experienced this occurence.

 

[iwire]

Some call it ghost voltage or phantom voltage

Phantom Voltages

 

[gaelectric]

Thanks for the short reply to a long question.

That document may come in very handy on Monday when I meet with the inspector again.

 

[iwire]

No problem, good luck.

 

[brian john]

I just did a report for a n EC having an issue with an electrical inspector exact same issue, if you'd like I can forward this to you.

 

[360Youth]

I had the same problem on a final a couple of weeks ago. We took apart the whole circuit ohming the wires and checking tension of the wire (it was a floor receptacle that I was able to remove and grab the wire under the floor). There was no signs of anything wrong, and when anything was plugged in (no load), the voltage went away. I eventually chalked it up to "phantom" voltage, but I am never fond of chalking it up.

Edit to add: Thanks for the link, Bob.

 

[LarryFine]

Thom, that's why many of us prefer using a low-impedance tester, such as a solenoid, for most testing and troubleshooting.

I only use a volt-meter if I need to know the exact voltage, and then, I make sure I'm reading between loaded conductors.

 

[fmtjfw]

Get a resistor

Get a resistor

I ordered Fluke SV225s for the guys on our crew. It is a 3Kohm resistor packaged in a little wart with two guarded male connectors to plug into your meter and two guarded female connectors to accept your test leads. It loads down circuits enough to eliminate phantom voltage readings and is rated CAT IV for up to 600V.

I leave it in my meter except when reading resistance or debugging 24V fire alarm circuits as it can trip them.

/s/ Jim WIlliams

 

[iwire]

 

[brian john]

I have been working with EC's and inspectors with the phantom voltage issue for 15-20 years, shouldn't the inspectors be aware of this by know.

Do most inspection agencies require continuing education?

 

[K8MHZ]

. .

 

[K8MHZ]

It's not stray or phantom voltage. It is EMF created by induction from conductors in close proximity of one and other. This phenomena is most prevalent with multiple switching. The available current is very low, nearly none, yet a high impedance meter will read the potential of the conductor and a tick tracer will indicate voltage on the conductor as well.

The best way to check is to use a solenoid tester. Home Depot has the Ideal Volt-Tecs for 20 bucks and the Vol-Cons for 35.

When I read this it reminded me of a house I was working in last week. When you turned the front foyer light switch off, the light would stay on. About 20 seconds later you would hear a click and the light would go off. I swapped out the switch and kept it. It does the same thing sitting on a bench with a continuity meter connected to it. It's a very old Leviton switch with the name on the handle.

 

[brian john]

It's not stray or phantom voltage.

While yo are right, it is necessary for education of inspectors and electricians to use common terms. Phantom or ghost voltage seems to be the terms of choice.

 

[Pierre C Belarge]

Do most inspection agencies require continuing education?

You have all heard me rant about this topic before...I love to rant. :grin:


In NYS, if you are breathing and have a pulse, then you are qualified to be an electrical inspector.
No prior time in the industry is necessary and no education is necessary either.

Once you become an inspector, the best way to stay an inspector is not to get caught doing the wrong thing.

Brian
How is that for an answer?

There are approximately 20,000,000 people in NYS. I wonder how many EIs there usually are per/person?
Not one in NYS is required by the state to have any, none, zilch, nada, education or experience in the field.

 

[gaelectric]

This particular inspector has been an inspector as long as I've been in the trade. Over thirty years. As he is not much older than myself I would figure that he has very little practical experience. He's been a PITA since I first met him 27 years ago when he worked for the city and I was a brand new RW.

He works for a company that makes inspections now and is like a sub-contractor to various jurisdictions. I have started to see this become more prevalent these days with the smaller towns subbing out the inspections instead of actually hiring employees. Makes it real hard to complain to their supervisors about anything.

 

[brian john]

Not one in NYS is required by the state to have any, none, zilch, nada, education or experience in the field.

Durn I'd fit in perfectly.

 

[iwire]

Do most inspection agencies require continuing education?

Here in MA they require it.

(1) Continuing Education Requirement.
(a) Except as otherwise provided in 237 CMR 17.01, each licensee of the Board, as a
condition for license renewal, shall present evidence satisfactory to the Board that in the
three year period before license renewal he or she has completed 21 clock hours of
continuing education. Of the required 21 clock hours, 15 clock hours shall be on topics
related to the Massachusetts Electrical Code, business, law and related topics with a
provider in area of study approved by the Board and six may be in a areas chosen by the
licensee for professional development in the subjects of Electrical Code, business, law,
first aid, Safety and Building Code and related topics. Notwithstanding the previous
provisions of 237 CMR 17.01, Inspectors of Wires appointed pursuant to M.G.L. c. 166, ?
32, electrical inspectors/ investigators employed by the Division of Professional Licensure
and members of the Board shall complete the required 15 hours of mandatory continuing
education within the first year of the release of the updated edition of the Massachusetts
Electrical Code, 527 CMR 12.00 as a condition of license renewal. In addition to the
required hours for renewal as provided above each Inspector of Wires appointed pursuant
to the provisions of M.G.L. c. 166, s. 32 shall complete two (2) six (6) hour certification
programs as required by the Board. For purposes of the immediately preceding sentence, a
certification program shall be defined as a Continuing Education Program sponsored by
an association of Inspectors of Wires approved by the Board.

 

[mxslick]

When I read this it reminded me of a house I was working in last week. When you turned the front foyer light switch off, the light would stay on. About 20 seconds later you would hear a click and the light would go off. I swapped out the switch and kept it. It does the same thing sitting on a bench with a continuity meter connected to it. It's a very old Leviton switch with the name on the handle.

Hang on to that switch!! It is a rare bird.. I seem to recall that there were toggle switches that were made with a delayed off time to allow someone to exit a room..you may have one of those, especially if the delay time is always 20 seconds plus or minus a second.

Any one else recall that, and are they still made?

 

[ultramegabob]

Hang on to that switch!! It is a rare bird.. I seem to recall that there were toggle switches that were made with a delayed off time to allow someone to exit a room..you may have one of those, especially if the delay time is always 20 seconds plus or minus a second.

Any one else recall that, and are they still made?

My parents house had those switches when I was growing up, they have all since been replaced. The house was built in the early 60s....

 

[Barjack]

It's not stray or phantom voltage. It is EMF created by induction from conductors in close proximity of one and other. This phenomena is most prevalent with multiple switching. The available current is very low, nearly none, yet a high impedance meter will read the potential of the conductor and a tick tracer will indicate voltage on the conductor as well.

The best way to check is to use a solenoid tester. Home Depot has the Ideal Volt-Tecs for 20 bucks and the Vol-Cons for 35.

When I read this it reminded me of a house I was working in last week. When you turned the front foyer light switch off, the light would stay on. About 20 seconds later you would hear a click and the light would go off. I swapped out the switch and kept it. It does the same thing sitting on a bench with a continuity meter connected to it. It's a very old Leviton switch with the name on the handle.

Just out of curiosity, could this phenomena cause an arc fault breaker to trip?