However if you need to rewire a light switch or a plug socket you may occasionally come across two black wires. A standard 2 wire lighting circuit is shown in figure 1.
Two Way Light Switching Explained
Light switch only has 2 wires. Line this comes from the panel and is your hot wire. While a standard switch does in fact only have two wires connected to it plus ground things can get a bit more complicated with a smart switch or multi way switches. The brown wire is live also know as permanent live this brings the live supply to the switch. Two or three wires will be attached to the switch. An incoming hot wire which is black. My apologies if this has been tackled before but im trying to replace an old light switch in my bathroom and the old one only had two black wires connected to it.
Depending on the manufacturer of the light fixture the. The easiest and safest way is to use a multimeter to test for current. An occupancy sensor that needs a neutral as well as the feed hot and hot to the light cannot be used where there are only two power wires not counting a bare or green ground wire entering the switch box. Its essential that you determine which black wire is hot before proceeding. Each light socket in a light fixture has its own black lead wire and white neutral wire. The blue wire is known as the switched live and takes power to the light.
And sometimes a grounding wire which is green or bare copperthere may be other wires in the box but you are only dealing with the ones connected directly to the switch. Switched live is only live when the switch is on this is where it gets its name from. White wires may not be mixed with or connected to bare or green ground wires. My old light switch in my bathroom only has two black wires connected to it. By your description though it doesnt sound like you have one. Black means hot white signifies neutral and green indicates ground.
A return wire which carries the load to the fixture and may be black red or any other color except green. As stated already if you have a bare green wire it is the ground and goes on the green screw that is on the switch. How to install a light fixture with two lead wires. Ill take a moment to outline each wire its typical color and its use huge disclaimer your wiring may vary.
Gallery of Light Switch Only Has 2 Wires
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