- Have a new circuit in the basement that includes a dimmer switch and 4 recessed lights, in addition to 6 outlets.
- The switch and the lights are at the end of the run. The order is:: panel > AFCI outlet > 5 outlets > switch > 4 recessed lights
- When a contactless tester (Kline Tools) is brought very near (about an inch) or touched any wire of the circuit, except the part between two last lights, it beeps/blinks red, which is correct.
- Checked the wiring (after turning off breaker) and all seem to be ok.
- All are new products from Home Depot. Tester is also ok and all outlets functioned ok, including AFCI outlet (trips and resets).
- When the tester is at about 12-14 inches from the wire between the two lights at the end of the run, it starts to beep and blink.
- Why is this happening?
- I'm planning on rechecking the wiring/connections etc., but any tips would be greatly helpful.
Electrical – Wire at the end of the circuit activates the tester at about 12-14 inches away
afcielectricalwiring
Related Topic
- Electrical – If a GFCI tester trips a circuit breaker is there a problem
- Electrical – Which is the hot wire, neutral wire and ground wire
- Electrical – Open ground on all outlets, voltage meter beeping on metal boxes and MC cable
- Electrical – Outlet tester results for open ground on mixed circuit
- Electrical – Open ground indication on tester when connecting appliances to any outlet on same circuit
- Electrical – Cut cable tripped breaker and left circuit dead after reset
- Electrical – Wiring a blank face afci, gfci and a regular outlets in a circuit, made a loud noise in gfci box
Best Answer
Those testers detect electromagnetic fields.
It's downstream of a dimmer
There are three dimmer technologies. Variacs are a variable transformer which steps down voltage, giving a sine wave, but they are huge and heavy. Rheostats are a variable resistor that adds impedance, giving a sine wave, but they make stupefying amounts of heat. Both of these, being sine waves (as in (a) below), produce a 60 Hz electro-magnetic field. (50 Hz in the rest of the world). Which is what that tester is designed to detect. However both those dimming methods are totally impractical for the home.
So a third method is used: semiconductor dimming, which uses electronic switching to alter the sine wave (as in (b) and (c) above). However, nature likes sine waves, and nature will treat a mutilated sine wave as if it were a conglomerate of various sine waves summing up. The science of this is called "Fourier analysis".
Which sine waves sum up to (c)? Many of them, at odd multiples (3x, 5x, 7x, 9x etc.) of the base frequency. So 180 Hz, 300 Hz, 420 Hz, 540 Hz, 660 Hz. and so on. Janky shaped waves can create lots of these and they can be strong. Depending on the setting of the dimmer, these other frequencies will have different strengths, and depending on the room, will propagate certain ways.
The tester's sensitivity to these harmonics will depend on its own design.
I bet all these factors are lining up in a way favorable to detection.