Its essential that you determine which black wire is hot before proceeding. However if you need to rewire a light switch or a plug socket you may occasionally come across two black wires.
Wiring A Control With 1 Black Wire One Red Wire And One White Wire Multilocation With A Pico
Why does my light switch have two black wires. Turn off the power and mark it so you dont confuse it with the 3 way circuit wires. The ground wires will be connected to each other and attached to the grounding screw on the switch. This connection is typically secured by a plastic wire nut. If one of the black hot wires does have power then that is the wire for the always on plug. Return to electrical article list. The normal colors of a residential outlet are black hot white nuetral and baregreen ground.
Switches are never connected between a black wire and a neutral wire. In most cases two black wires will be attached to the switchs two terminal screws. Black means hot white signifies neutral and green indicates ground. The white wires will be connected to each other but not to the switch itself. The easiest and safest way is to use a multimeter to test for current. The three way switch is a variation of the standard single pole switch which controls a light only from one locationa third type is the four way switch which is used in conjunction with two three way switches to control lighting from more than two locationsthis configuration may be used in open plan homes or in large kitchens or great rooms where a central bank of lighting fixtures might.
The hot wire leading from the 3 way switch circuit will have no power since all power must travel through the switches. 3 wire lighting systems the 3 wire system is less common than the 2 wire system it includes a neutral at the switch as well as the live and switched live wires. If you have a 2 gang or 3 gang switch you may have black and grey wires however these will have a brown sleeve on them as they are also switched live wires. The two black wires one is power input the other is switched power output is used to control a light fixture or outlet. It is common to feed thru an outlet in other words to bring the power in on one trio of wires.