# Multimeter Readings on House Wiring

• posted on January 26, 2007, 3:32 pm

I am currently replacing an old fluorescent light fixture with three recessed lights.
A 20 amp fuse (not breaker) was used for the circuit that contained this fluorescent light and the over-the-range microwave. The previous-to-previous owners did much of the work in the house themselves and usually did a poor job at it (for example, after taking down some drywall we discovered rot everywhere that lead to finding out the the overflow pipe that connects to the bath tub was never fitted with the rubber gasket so there was an inch gap that lead to the tub leaking whenever a bath was taken - they instead CAULKED the overflow outlet in the tub).
In this situation the main feed from the fuse goes somewhere (sorry I can't be more helpful); an outlet box that is about 1/2' from the ceiling (weird I know) has a 3-wire cord (red, black, and white) coming from the ceiling and contained a splice to a 2-wire cord (black and white) that connected to the fluorescent light (with electrical tape). I ripped all the tape apart and removed the outlet box as we'll be permanently removing and filling in the hole where that was - unfortunately I didn't look to closely how the wires were connected.

cord and all that is left is the 3-wire cord that I hope to use for the three recessed lights.
I took a multimeter to the three wires and this is the result:
SWITCH OFF black & red = 26V black & white = 120V red & white = 18V
SWITCH ON black & red = 0V black & white = 120V red & white = 120V
A single switch controls the light fixture but the microwave is always on. Unfortunately I cannot see behind walls to well and I am not sure how everything is connected, but if persuaded I'll delve deeper.
Any ideas on what is going on? Is the black and white used together for the microwave but is for some reason still fed up to the light fixture? What do I splice together out of the three to form one hot and one neutral?
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• posted on January 26, 2007, 4:03 pm
I'd also like to add that the swithch is a two-way switch and not a three-way switch.
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<%-name%>
• posted on January 26, 2007, 4:06 pm
After looking further, I'm guessing the black is the always hot and was used to supply a steady current to the outlet near the ceiling. This outlet will no longer be there - can I properly terminate the black wire (how) and then just use the red and white wire to power the recessed lighting?
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<%-name%>
• posted on January 26, 2007, 6:14 pm
On 26 Jan 2007 08:06:15 -0800, GG& snipped-for-privacy@amiraclecomputers.com wrote:

I hope you're not trying to do all of this in your head.
Make a diagram/drawing of all the wires, etc, including wire color of course.
After the first diagram is made, redo it on another sheet of paper, trying to make it logical rather than just visual. That is, if two wires go to the same place, group them together in the second drawing even if they weren't when you look at the actual wires. Make the drawing so it helps you understand what is going on, piece by piece.
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<%-name%>
• posted on January 26, 2007, 6:29 pm
On Jan 26, 1:06 pm, snipped-for-privacy@amiraclecomputers.com wrote:

Sounds like you are 'on the right track'. White should be /usually is neutral all the way back to the fuse/circuit beaker panel. Neutrals are not switched. But see note 2 about 'white wires'. Black is usually (although us amateurs can be capable of all kinds of miswiring!) the live lead from the breaker panel. The red sounds like it is the 'switched live' for the light fixture. Two notes: 1) Fluorescent fixtures should be and work better when grounded. 2) While in your case the red seems to be the switched live (and this is not to confuse you) occasionally one can encounter a white wire that is a 'switched live'. For example: In this jurisdiction the inspectors prefer that one use red/black to wall switches; the black takes the 'live' lead to the wall switch and the red comes from the other side of the switch to the light fixture/s. But sometimes the electrician didn't have red/black and used white/black, in which case the white 'switched live' is supposed to be marked in some way (I sometimes use red nail polish or red tape) but often is not.
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<%-name%>
• posted on January 26, 2007, 6:46 pm
mm, thanks for the insights but I definitely understand what is going on (and have it written down anyways).
terry, thanks very much for the reply an yours is more of what I am looking for. The red is definitely the switched wire, I just need to know how to properly terminate a single wire (the black) as I will no longer have the outlet there. I don't want to just put a nut on it - what is the proper way to terminate a single wire? I'm almost thinking that is why they put the outlet there in the first place - to terminate the black wire - as this outlet/light fixture is in the middle of the circuit and comes from the microwave. The outlet was in such an illogical place (1/2 near the ceiling!?) that it just really makes me think that's what they did. I also agree that there should have been a ground wire for the flourescent light - I installed a new flourescent light about 12' away from this one that I took down and there was a ground wire available there...
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<%-name%>
• posted on January 26, 2007, 7:05 pm
On Jan 26, 12:46 pm, snipped-for-privacy@amiraclecomputers.com wrote:

If you're not using it, just put a wire nut on it and go on. I'd tape it for a little added comfort, but it really doesn't do anything the nut didn't/won't do other than add a little extra to keep it in place. But, if you use the proper size, it'll be tight, anyway.
The "better way" would be to go back to the feed junction and disconnect it from the feed there. If there is no future need for it, it could then be cut off flush at each end. Failing that, the best is to cap it where the present box/junction is so it is accessible for future.
Whatever this box is presently, even if you use it no longer for any purpose other than the junction, it must not be covered over by a wall finish of some sort (drywall, paneling, etc.) but must remain accessible.
I'm almost thinking

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<%-name%>
• posted on January 26, 2007, 7:10 pm
Thanks dpb,
I will just find a proper fitting nut and put that on. I already removed the box as each recessed light already has it's own box for housing the splices. Thanks again!
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<%-name%>
• posted on January 26, 2007, 6:39 pm

of the high sensitivity of many multimeters to even small 'induced' voltages. It's better to use a light bulb/test lamp. For example the 26 volts could just be voltage picked by one wire running adajacent to another wire (capacitve coupling etc.) to a live wire for suitable distance. the fact that the red to black drops to zero (i.e. both wires joined together when the switch is 'on') seems to prove that. Als the fact that you get 120 volts on the red wire when the swich is on also seems to prove that red IS the switched live for your new (non fluorescent, rereading the OP). A final question; where is the ground (bare coper or green or green/yellow) for any metal joining boxes and the new light fixtures?
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<%-name%>
• posted on January 26, 2007, 6:49 pm
To add, there is no ground wire on this circuit (unless it stopped at the microwave).