# How Does 2-Pole Circuit Breaker Work?

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Most homes have one or more double-pole circuit breakers in the electrical panel. These breakers control 240-volt circuits that power large appliances, such as electric water heaters, dryers and ranges. A double breaker is basically an interconnected set of two single-pole breakers. Each one snaps onto a different hot bus in the panel, and because they're interconnected, they trip at the same time. Double-pole breakers are usually rated for current in a range between 30 and 60 amps.

How Does 2-Pole Circuit Breaker Work?
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## How Electricity Gets to the Panel

Each circuit in the house is wired to the electrical panel, which is the point at which the power enters the house from the transmission line. A transformer mounted on the power pole steps the line voltage down to 240 volts, more or less. Wire resistance and other factors often reduce this to 220 volts. This energy comes to the house in the form of two hot wires with the transformer output voltage between them. Each hot wire is connected to a hot bus bar in the panel, and a third bus â€“ the neutral â€“ is connected to the transformer by a third wire. The voltage between each hot bus and the neutral bus is 120 volts, while the voltage between the two hot buses remains at 240 volts.

## How a Normal Circuit Breaker Works

A number of manufacturers produce electrical panels, and each one designs the panel in such a way to accept the breakers they manufacture. A 120-volt breaker typically clips onto one of the bus bars when you snap it into place. When you connect a hot circuit wire to the breaker and the neutral wire from that circuit to the neutral bus, the voltage in the circuit is 120 volts. The breaker is designed to detect current surges, such as those caused by overloads or short circuits, and to automatically shut off when one occurs. Single-pole breakers are usually rated for 15 or 20 amps and will trip when the current exceeds their rating. The purpose of the breaker is to prevent electrocution, fire and damage to electrical equipment.