The most likely error is that the wire going to the light that stays on is contacting one of the live wires. To check, disconnect all the wires from each other, turn on the breaker and use a voltage tester to identify the live circuit wire.
Is there still power to a light when switch is off?
Power to the light box, and a loop to the switch. Even with the switch off, there are live wires at the light. You should be just fine with the light switch turned off. If the light switch is not in close proximity to the socket where you will be working, place a sign over it or tell family members to not touch it.
Why do I have a voltage reading when light switch is off?
Just to recap, a “phantom voltage” is where a wire from a switch to a light or outlet runs next to a permanently live wire, when the switch is off, the AC voltage in the other wire can induce a voltage in the switched-off wire.
Why is wire hot when switch is off?
Sounds like the switch is after the light, ie) power goes to the light then to the switch. In this case the black is always hot and the white from the switch is also hot, but controlled by the switch. The other part of this is whether the person who wired the switch and light knew what they were doing.
Can I just turn off the switch to change a light fixture?
Before you start, you’ll need to turn the electricity off in the area you’re working. It’s not enough to shut the power switch off on the wall. Go to your circuit panel and flip the circuit breaker for the room or area you’ll be working.
Does power go to light or switch?
With power-through wiring, power enters the switch box directly. The feed wire (the hot wire coming from the service panel) runs to the switch before it goes to the fixture.
Why does ceiling light stay on?
A ceiling light might stay on when the switch is off due to its wiring. If the light is connected directly to the hot wire, it will maintain the electrical current whether the switch is on or off. To fix this issue, the light has to be connected to the switched leg conductor.
What causes phantom voltage?
Conductors that are installed in close proximity to one another, and are capacitively coupled to each other, can cause this a.c. voltage reading. Such a reading could be 2 or 3 volts, or it may be as high as the voltage on the adjacent conductors. This is what is referred to as a “phantom” voltage.
What causes backfeed voltage?
Backfed voltages are voltages that often originate from another circuit or part of the equipment, but “backfeed” through indicating lights, control power transformers or even resistors in equipment.
How do you check voltage on a light switch?
With the selection knob on the instrument set to AC, touch one probe to a grounding wire, then touch each of the metal screw terminals on the switch, one at a time. If the needle or LED readout on the tool’s display indicates voltage, the power has not been properly turned off.
How do you change a light switch without turning off the breaker?
Quote from Youtube video: On/off. The light no longer comes on grab a flathead screwdriver. And remove both the top. And lower screw. Once the screws are loose we can remove the cover plate.
Do you have to turn off the breaker to install a ceiling fan?
Whether you are replacing an existing light fixture or installing the fan and connecting electrical wires to it, you must be sure that you have turned off the circuit breaker or removed the fuse governing the circuit where the fan will be connected.
How do you wire a switch with power at light?
Quote from the video:
Quote from Youtube video: You were allowed to use a two wire cable for this so there's many situations out there where this is the case you only have a black and a white coming down from the light fixture to the switch.
What happens if I wire light switch wrong?
But here’s the catch: If you connect the circuit wires to the wrong terminals on an outlet, the outlet will still work but the polarity will be backward. When this happens, a lamp, for example, will have its bulb socket sleeve energized rather than the little tab inside the socket.
Does it matter what wire goes where on a light switch?
It doesn’t matter as long as you do it the same on both switches. So, if you connect it to the upper right terminal on one switch, connect it to the upper right terminal on the other switch. Connect the second traveler wire to the terminal opposite the red wire terminal.
What is a switch loop in wiring?
Quote from the video:
Quote from Youtube video: Well you can still get a complete loop wiring a switch loop so what a switch loop is is instead of running a hot to your box first for your switch.
How do you wire a ceiling light with a loop?
Quote from the video:
Quote from Youtube video: This is the cable that is connected to the consumer unit the brown wire connects to the loop terminal. The blue wire connects to the neutral terminal and the earth wire connects to the earth terminal.
What happens when you loop a switch?
Switching loops also generate broadcast storms, since the broadcast packets are forwarded to every port on the switch; the switch will repeatedly rebroadcast the broadcast messages, thus flooding the network. When this happens on your network, everyone will lose the ability to communicate on the network.
Are switch loops allowed?
At the fixture end, one of the 2 wires the switch is connected to would be connected to the source of power (black on the other cables) and the other is connected to the hot screw of the light fixture. A switch loop wired properly is legal.
Is the black wire hot?
Here’s a rundown of electrical wires: The black wire is the “hot” wire, it carries the electricity from the breaker panel into the switch or light source. The white wire is the “neutral” wire, it takes any unused electricity and current and sends it back to the breaker panel.
Do you need a neutral at a switch?
Neutrals. When wiring lighting circuits supplied by a grounded general-purpose branch circuit, the 2011 NEC now requires you to provide a neutral conductor at nearly every switch point [404.2(C)]. The purpose for this is to complete a circuit path for electronic lighting control devices, such as occupancy sensors.
