> >
>

# Wiring question: losing my mind or wildly ignorant?

#1
04-04-20, 05:14 PM
Member
Join Date: Nov 2017
Location: Costa Rica
Posts: 13
Wiring question: losing my mind or wildly ignorant?

I have a 10 meter section of cable that is a standard 3 wire cable with three #12 copper wires in it. I've tested this cable disconnected from everything and there are 0 ohms across any of the 3 possible combinations (red-white, red-black, and white-black). I assume then that there is no short in this cable.

I have a wall socket in my house with a hot black wire and a neutral wire. I read 123 volts across these two. So far, everything seems ok.

The first connection I make to any of this is to connect the hot black from the house to the black lead of the 10m three wire cable from above. In essence the only thing I've done is extended the length of the hot lead from the house to the end of the 3 wire cable. That's it...nothing more.

However, I now measure the voltage difference between the white lead from the 10m cable and the white neutral wire from my house and I read 32 volts ?!?! Huh ?!?! There should be no continuity between the white and black wires inside the 10m cable.

I then connect the white wire from the cable to the white neutral from the house - not even a tiny spark. However, I get .1 amps (12.3 watts) being read by my Fluke tester. So, I have 12 watts running through an unconnected circuit. I am beside myself. I know enough to have heard of inductive currents. Is that what this is? 12 watts seems like a lot of power to burn just to extend the length of a cable by 10m. What on earth could be going on. Here is an image of the above description in case the description wasn't clear enough.

04-04-20, 05:40 PM
joed
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 7,325
0 ohms is a short. Can we assume you meant zero reading or infinite ohms?

However, I now measure the voltage difference between the white lead from the 10m cable and the white neutral wire from my house and I read 32 volts ?!?! Huh ?!?! There should be no continuity between the white and black wires inside the 10m cable.
Phantom voltage. It is a normal problem with hi impedance digital meters.

I then connect the white wire from the cable to the white neutral from the house - not even a tiny spark. However, I get .1 amps (12.3 watts) being read by my Fluke tester.
How are you measuring the watts?

#2
04-04-20, 05:37 PM
Member
Join Date: Feb 2016
Location: United States, Virginia
Posts: 1,318
You are getting false readings. You an analog meter or test light.

EscapedArtist voted this post useful.
#3
04-04-20, 05:40 PM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 7,325
0 ohms is a short. Can we assume you meant zero reading or infinite ohms?

However, I now measure the voltage difference between the white lead from the 10m cable and the white neutral wire from my house and I read 32 volts ?!?! Huh ?!?! There should be no continuity between the white and black wires inside the 10m cable.
Phantom voltage. It is a normal problem with hi impedance digital meters.

I then connect the white wire from the cable to the white neutral from the house - not even a tiny spark. However, I get .1 amps (12.3 watts) being read by my Fluke tester.
How are you measuring the watts?

CasualJoe, EscapedArtist voted this post useful.
#4
04-04-20, 05:44 PM
Member
Join Date: Feb 2016
Location: United States, Virginia
Posts: 1,318
Does your fluke have a low impedance setting?

#5
04-04-20, 08:31 PM
Member
Join Date: Nov 2017
Location: Costa Rica
Posts: 13
Thanks for the responses. Yes I meant infinite resistance...shouldn't have made that mistake.

I'm getting the watts by multiplying the .1 amps by 123 volts. But, I suppose it could be just 3.2 watts because the voltage was just 32 volts. But that doesn't change why I'm seeing any volts at all and especially why I'm seeing current. Does one wire, lying next to another wire that has an AC charge, build up voltage from the simple fact that it is lying next to that charged wire? 32 volts isn't the end of the world, but it seems radical to me...at least I've never witnessed this before.

My meter is a Fluke T5600. It doesn't say high-impedance and has no impedance switch that I can find.

#6
04-04-20, 08:42 PM
Member
Join Date: Nov 2017
Location: Costa Rica
Posts: 13
Hi Pattenp,

I don't have an analog meter. I always liked the digital ones because they are so easy to read but I'm obviously a novice at this. Should I reconsider using digital meters? I've never seen a problem like this!

I do have a non contact voltage detector (came in the kit with the meter). The whole reason I found this issue is that it was blinking weakly on that line with the weak voltage. I thought I had some sort of leakage across the wires, but I doubt that now after testing.

You say, "you are getting false readings". Does that mean a faulty fluke reader, or does that mean an over sensitive reader and I need to get used to seeing voltage like this? I certainly don't like to see any voltage that I'm not expecting

#7
04-04-20, 08:56 PM
Forum Topic Moderator
Join Date: Mar 2008
Location: United States
Posts: 8,810
No meter problem, Means meter to sensitive for household use.

#8
04-04-20, 09:04 PM
Member
Join Date: Nov 2017
Location: Costa Rica
Posts: 13
I have now read a bit on phantom voltage. I only remain confused about the .1 amp current, but I just tested that once and without being really careful, so I will assume for the moment that my problem was indeed phantom voltage. With no spark at all on the 32 volts I witnessed, I have to assume there was not much if any current. Cased closed on a newbie. Thanks for the quick replies!!

#9
04-05-20, 05:35 AM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 7,325
How are you measuring amps? I think everything is OK. It is just the sensitivity of your meter and how you are using it.

#10
04-06-20, 02:57 PM
Member
Join Date: Nov 2017
Location: Costa Rica
Posts: 13
Hi Joed,

I just quickly stuck the hot wire in the current U of the meter. I glanced at it and saw .1. But the whole thing was jammed up against the wall with other wires nearby and that was not a careful reading. I had assumed, with the voltage, that I would indeed get some current, so I didn't think to measure it carefully and then double check. Now it is all sewed up so I don't want to go in and measure again.

#11
04-06-20, 04:38 PM
Member
Join Date: Sep 2002
Location: welland ontario
Posts: 7,325
Dangerous. If there was any power on that circuit the meter would have acted as a short, tripped the breaker and possibly blown up in your face. Current measurement always has to have a load.

#12
04-16-20, 01:33 PM
Member
Join Date: Nov 2017
Location: Costa Rica
Posts: 13
I might not understand your point, but I was measuring current with a non-invasive meter...a current clamp...one of those U shaped things the just wraps around an insulated wire.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Pingbacks are Off
Refbacks are Off