What If Both Wires Are Black?

Why does light switch have 2 black wires?

The bare or green-wrapped ground wires serve as a backup to divert the power safely away in case of an electrical fault.

In most cases, two black wires will be attached to the switch’s two terminal screws..

What happens if you mix up hot and neutral wires?

This happens when the hot and neutral wires get flipped around at an outlet, or upstream from an outlet. Reversed polarity creates a potential shock hazard, but it’s usually an easy repair. … This wire is commonly referred to as the neutral wire, and it should always be white.

Is the black wire positive or negative?

Positive – The wire for the positive current is red. Negative – The wire for the negative current is black. Ground – The ground wire (if present) will be white or grey.

Why are both black and white wires hot?

like the title says both wires (black and white get or turn hot). To answer your question, Yes, that is correct. The reason you are getting 120 volts when the fan/light is on is because the voltage is feeding trough the motor or the light bulb (or both).

Is black wire hot?

Black, Red and Blue are used for hot wires and White is used as the neutral wire in a 120/208 V circuit. Brown, Orange and Yellow are used as hot wires and gray is used as the neutral wire in a 277/480 V. For grounding, regardless of the voltage, Green (or a bare wire) is used.

How can you tell which wire is hot without a tester?

For example, get a light bulb and socket, and attach a couple of wires to it. Then touch one to neutral or ground and one to the wire-under-test. If the lamp lights, it is live. If the lamp doesn’t light, then test the lamp on a known live wire (like a wall socket) to make sure it actually lights.

What happens if you wire a light switch backwards?

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. … The white (neutral) wire should be connected to the silver-colored terminal. If these connections are backward, the polarity is wrong.

How do you connect two black wires together?

Connect the top screw to the wire that feeds to the light. Connect the bottom screw to the hot wire. When you turn the power back on, and if you want to swap the direction of the switch (as in press down to turn off, or turn on), turn off the power and switch the two black wires.

Can Reverse polarity cause a fire?

Watch out: Reversed polarity on an electrical outlet is dangerous. If you accidentally reverse these wires the device you plug in to the receptacle may “work” but it is unsafe and risks a short circuit, shock, or fire.

What happens if you connect 2 hot wires?

You either have no voltage difference between the two wires, or you will get hot wires from opposite hot legs and you will end up with a 240 volt dead short. In that case you will trip at least one circuit breaker, or possibly 2. … If you bring two hots to the switch from the same phase, nothing will happen.

Is black positive or negative?

Car batteries, like regular AA batteries, have positive and negative ends. The positive (+) end is identified with a red plastic cover or connected to red wires, while the negative (-) end will have black markings.

Why would a light switch have 3 black wires?

If the light turns on, the second black wire you connected to the switch is the switch feed and the unconnected black wire is the feed to the other loads. If the light doesn’t turn on, then it’s the other way around: the connected wire feeds the other loads and the disconnected wire is the light feed.

Why does my outlet have 2 black and 2 white wires?

Since this one has more, it means it is part of a “series”. A “series” means there are 2 or more outlets powered by the same wiring and circuit. The other set of black and white wires goes to the next outlet down the line and that’s how it gets its power.

How do you tell if a wire is hot?

Confirm that the circuit tester is working by carefully touching the hot wire with one lead and a neutral wire with the other. The tester will light if it’s working. Touch the hot wire with one lead and the ground wire with the other (Photo 1). If the tester lights, the ground wire is good and you can use it.

Which wire is hot when both are same color?

In most modern fixtures the neutral wire will be white and the hot wire is red or black. In some types of fixtures, both wires will be the same color. In this case, the neutral wire is always identified by some means.

Which wire is positive when both are black?

If the multi-colored wire is black and red, the black wire is the negative wire, while the red one is positive. If both wires are black but one has a white stripe, the striped wire is negative, while the plain black wire is positive. Look in the owner manual to determine which wires are negative in a car.

What happens if I wire a light wrong?

You could put the switch on the neutral wire and everything would work, but it would leave voltage potential to ground in the light when it is switched off. That makes it a bit hazardous for changing light bulbs. If you became an electrical path to ground through a wet floor or something you could get a shock.

How can you tell if a wire is load or line?

Load Wire – Generally connected to the top half of your switch. If the wire is coming from the top of the switch box, it is likely your load wire. Line Wire – Generally connected to the bottom half of your switch. In some cases, line wires are marked with “line”, “pwr”, or a lightning bolt symbol.

Is hot wire on top or bottom of switch?

If you are speaking of a single pole switch, doesn’t matter. On a 2 pole switch, box mounted, technically it doesn’t matter, but good practices are line at the top, load at the bottom. If a disconnect switch, always line at the top, load at the bottom.

What if my light switch has no ground wire?

Going without a ground wire If the light switch has a screw for a bare ground wire but your electrical box doesn’t have one, you’re OK just leaving that screw empty and connecting your other wires to the hot screws. … If the box isn’t grounded, the switch will still work.