# What If I Have Two Black Wires?

## How can you tell if a wire is positive or negative?

If you have a wire where both sides are the same color, which is typically copper, the strand that has a grooved texture is the negative wire.

Run your fingers along the wire to determine which side has the ribbing.

Feel the other wire which is smooth.

## 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.

## Why would a neutral wire be hot?

If the neutral is disconnected anywhere between the light bulb and the panel, then the neutral from the light to the point of the break in the neutral will become hot (and the device will be unpowered, because no current will be flowing through it). … It might be best to temporarily unscrew any such bulbs.

## Will an outlet work if wired backwards?

This makes things like lamps and many appliances more safe to operate. 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.

## What happens if you wire a light switch backwards?

A light switch is a simple device with only two states, competing a circuit (On) or breaking a circuit (Off). It is a series control element is a series – parallel circuit design. A light switch has no polarization so when you reverse the connections on the light switch it works just as before you reversed the wires.

## Which wire is hot if both are black?

The black wire is the “hot” wire, which carries the electricity from the breaker panel into the switch or light source. The white wire is the “neutral” wire, which takes any unused electricity and current and sends them back to the breaker panel.

## What if my light switch has no 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. In many cases, especially in older houses with metal boxes, the metal box may be grounded even if you don’t have a ground wire.

## How do I know if I have a hot or neutral wire?

Identify the neutral wire in the fixture by looking at the wires. 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.

## Why does my 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.

## 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.

## Why does my light switch have 3 wires?

A three-way switch is a handy convenience to control a light from two locations, such as at the top and bottom of a staircase. If the words On and Off aren’t embossed on the switch and it’s one of two switches that control a single light or receptacle, you have a three-way switch.

## What do I do if I have two black wires?

Black means hot, white signifies neutral, and green indicates ground. However, if you need to rewire a light switch or a plug socket, you may occasionally come across two black wires. It’s essential that you determine which black wire is hot before proceeding.

## What happens if you reverse 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.

## Is black positive or negative?

Step 3: Identify the jumper cables: Red is for the positive charge, black for the negative. The thicker the cables, the better the jump. Don’t let the clamps of the opposing cables touch, or you may get a shock. Step 4: Take the red jumper cable and affix one clamp to the positive post of the dead car battery.