Baumgrenze
Member
Recently I restored to working the 3 switch light circuit that powers a single, utility incandescent bulb in the 2-car garage of our vintage 1955 tract home. We are the third owners and started our tenure in 1971.
I used this tutorial on my first try to restore all 3 switches to service. Despite the clear instructions I failed:
http://users.wfu.edu/matthews/misc/switches/4WayStills.html
Therefore I made a more methodical examination of the circuit.
The circuit, 3 switches (2 at the driveway doors and 1 at the house door,) predates 1971. I point this out because the 4-way switch is furthest from the 3-way switch at the garage/house door where the power is supplied.
I disconnected that switch and was troubled to discover there was a ~20% difference in the voltage to ground for the 2 hot leads, 1 black and 1 white, when the circuit was powered. The second black lead, a neutral, was at 0V to ground. The hot black lead read 96V and the white lead read 122V.
What might explain this difference? Should I be concerned about it? The light works as intended.
Thanks,
baumgrenze
Notes:
All of the original wiring is 12 gauge with ground in classic silver insulation.
This means that the line to the 4-way switch ran past the location of the other driveway 3-way and a second cable back across the garage was needed to install the second driveway switch. This was done when copper was very expensive and hard to obtain because of the Korean War effort.
I used this tutorial on my first try to restore all 3 switches to service. Despite the clear instructions I failed:
http://users.wfu.edu/matthews/misc/switches/4WayStills.html
Therefore I made a more methodical examination of the circuit.
The circuit, 3 switches (2 at the driveway doors and 1 at the house door,) predates 1971. I point this out because the 4-way switch is furthest from the 3-way switch at the garage/house door where the power is supplied.
I disconnected that switch and was troubled to discover there was a ~20% difference in the voltage to ground for the 2 hot leads, 1 black and 1 white, when the circuit was powered. The second black lead, a neutral, was at 0V to ground. The hot black lead read 96V and the white lead read 122V.
What might explain this difference? Should I be concerned about it? The light works as intended.
Thanks,
baumgrenze
Notes:
All of the original wiring is 12 gauge with ground in classic silver insulation.
This means that the line to the 4-way switch ran past the location of the other driveway 3-way and a second cable back across the garage was needed to install the second driveway switch. This was done when copper was very expensive and hard to obtain because of the Korean War effort.