donnyjamon
Member
why do i still get a 20 va reading on my meter at a light at the end of a 3 way switch when the switch is off and the regular 120 va when it is on ?
voltage in a 3 way
- Thread starter donnyjamon
- Start date
- Status
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Your use of the term "va" is confusing me. Do you mean volts (as opposed to volt-amps)? Two more questions: (1) Where are you taking measurements (i.e., between which two points)? (2) What measuring device are you using?
Welcome to the forum.
Welcome to the forum.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
If there is a dimmer in the circuit you will read some voltage even with the switch off, otherwise you should not be reading voltage.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Donny, welcome to the forum! 
If you had a light bulb in parallel with the meter leads, you wouldn't read that voltage. That's why many of us prefer a lower-impedance tester for general troubleshooting, and save the meter for when we need to know the exact voltage.
What you're reading is usually called "phantom voltage."
Presuming you do mean volts, you're reading some voltage because the meter has such a high input impedance (meaning it uses very little current), it's reading voltage impressed on the 'dead' wire just by having hot wires around it.
If you had a light bulb in parallel with the meter leads, you wouldn't read that voltage. That's why many of us prefer a lower-impedance tester for general troubleshooting, and save the meter for when we need to know the exact voltage.
What you're reading is usually called "phantom voltage."
donnyjamon
Member
phantom power
phantom power
Hey guys,
Let me first say thanks for your help.
This house was built by Mickey Mouse himself and were trying to get everything back to code.
I am using the fluke T5-600 tester and I am testing on the wire that will be going to a light which is on a 3 way. I have hurd the term phantom power before in school but have never seen it.
The first switch in the 3 way has its feed power jumped from 2 other switches which go to a celing fan and its light. From that main feed there is also 1 receptical. Now back to the 3 way, it takes its power from that main feed and powers 2 lights and i get a 20v reading on my meter. I put wiggies on and they say nothing.
I think i can see why i am seeing 20 volts from "phantom power"
Would this set up be against code? if you can figure out what i am saying haha sorry.
It use to power a bathroom fan and light on top of that but i took that out of the circuit.
Does this sound safe or should we bring in a whole new feed ?
Thank you very much
-DJ
phantom power
Hey guys,
Let me first say thanks for your help.
This house was built by Mickey Mouse himself and were trying to get everything back to code.
I am using the fluke T5-600 tester and I am testing on the wire that will be going to a light which is on a 3 way. I have hurd the term phantom power before in school but have never seen it.
The first switch in the 3 way has its feed power jumped from 2 other switches which go to a celing fan and its light. From that main feed there is also 1 receptical. Now back to the 3 way, it takes its power from that main feed and powers 2 lights and i get a 20v reading on my meter. I put wiggies on and they say nothing.
I think i can see why i am seeing 20 volts from "phantom power"
Would this set up be against code? if you can figure out what i am saying haha sorry.
It use to power a bathroom fan and light on top of that but i took that out of the circuit.
Does this sound safe or should we bring in a whole new feed ?
Thank you very much
-DJ
brian john
Senior Member
- Location
- Leesburg, VA
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Eureka! The wiggy, a solenoid-type tester, is a low-impedance load, and is what I use.
- Status