I was shocked into learning something new

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
I guess I should have known this, but ...

I was replacing a light fixture in a bathroom. Rather than turn off the breaker, I just turned off the light switch. I noticed that the light switch had a night light in the handle, but I didn't think anything about it. While handling the conductors, I got a little tingling shock when I touched both the hot and ground with my fingers. That's when I realized that the night light is probably working by leaking current to ground. Oops. Lesson learned.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
I guess I should have known this, but ...

I was replacing a light fixture in a bathroom. Rather than turn off the breaker, I just turned off the light switch. I noticed that the light switch had a night light in the handle, but I didn't think anything about it. While handling the conductors, I got a little tingling shock when I touched both the hot and ground with my fingers. That's when I realized that the night light is probably working by leaking current to ground. Oops. Lesson learned.
There ought to be a rule saying there has to be a neutral in the switch box for such loads as lighted handles so the EGC isn't used for that purpose.

:ROFLMAO:
 

GeorgeB

ElectroHydraulics engineer (retired)
Location
Greenville SC
Occupation
Retired
There ought to be a rule saying there has to be a neutral in the switch box for such loads as lighted handles so the EGC isn't used for that purpose.

:ROFLMAO:
The ones I recall had the neon and resistor across the switch contacts. It lit when the switch was off (assuming a good lamp).
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
I guess I should have known this, but ...

I was replacing a light fixture in a bathroom. Rather than turn off the breaker, I just turned off the light switch. I noticed that the light switch had a night light in the handle, but I didn't think anything about it. While handling the conductors, I got a little tingling shock when I touched both the hot and ground with my fingers. That's when I realized that the night light is probably working by leaking current to ground. Oops. Lesson learned.
If the light in the handle is only on when the light is off, it is probably getting its power by putting the light in series with the load when the switch is "open" In that case it is not leaking current to ground, it is leaking current onto the switched hot to the fixture.
If this is the case, the night light should go out when the fixture is disconnected or the bulb removed.
 

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
In that case it is not leaking current to ground, it is leaking current onto the switched hot to the fixture.
Which is consistent with the OP's report, that they got a mild shock when across (switched) hot at the fixture and ground. While if the lighted switch was using the ground as the return, then you wouldn't expect any potential difference at the fixture.

Cheers, Wayne
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
If the light in the handle is only on when the light is off, it is probably getting its power by putting the light in series with the load when the switch is "open" In that case it is not leaking current to ground, it is leaking current onto the switched hot to the fixture.
If this is the case, the night light should go out when the fixture is disconnected or the bulb removed.
This, and it doubles a bulb-condition indicator.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Many years ago, I wired an older house in the city, the kind on a deep, narrow lot. There was a garage on the alley at the back of the back yard, so I put one flood and one spot bulb in the 2-bulb light fixture, which lit the deep yard well.

The garage light had been wired with 3-way switching, but you couldn't see whether the light was on from the house. I added an NE-2 bulb and a pair of 100K resistors to the 3-way inside the house, and drilled a small hole in the plate.

The two resistors are wired in series, with one end on each traveler, and the NE-2 wired from the point between the resistors to the neutral. If the NE-2 is on, so is the light. If it's off, so is the light. If it won't come on, the bulb is out.
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
When I was very small, I was fascinated with electronics and I built many Radio Shack kits. While perusing an electronics supply house magazine I found I could get 100 neon bulbs for just a few dollars. Well of course I ordered them. I never did anything with them, but having them made me feel rich.
 
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