In electrical work, a single-pole switch or breaker controls just one wire, usually the hot wire in a 120V circuit. It’s the kind you’ll find on most light switches and basic outlets. A double-pole switch or breaker controls two hot wires at the same time, which is needed for 240V circuits and larger appliances like dryers or stoves.

Here is a breakdown of the basic characteristics of a single-pole switch vs. a double-pole switch and a single-pole breaker vs. a double-pole breaker, including examples of cables that would typically be used with each.

Switches

Single-Pole Switch:

• Controls one hot wire

• Used for 120V circuits like lights or small appliances

• It has two terminals and a ground

• Doesn’t fully disconnect: neutral remains connected

• Example: a standard light switch

Common cables:

• 14/2 NM-B (Romex) for 15A lighting circuits

• 12/2 NM-B for 20A outlets or appliances

• 12/2 UF-B for underground runs to outdoor lights or outlets

Double-Pole Switch:

• Controls two hot wires at the same time

• Used for 240V circuits and higher loads

• Has four terminals and a ground

• Provides full disconnection — safer for maintenance

• Example: switch for a water heater, stove, or dryer

Common cables:

• 10/3 NM-B for 30A dryer circuits

• 8/3 NM-B for 40A electric ranges

• 2-2-2-4 SER cable for feeding subpanels or main service

• MC 8/3 cable or THHN 8 AWG in conduit for commercial or exposed applications

Breakers

Single-Pole Breaker:

• Interrupts one hot wire

• Supplies 120V

• Usually rated 15–20 amps

• Used for lights, outlets, and general-use residential circuits

• Occupies one panel slot

Common cables:

• 14/2 or 12/2 NM-B

• 12/2 UF-B for underground wiring to outdoor outlets or garden lights

Double-Pole Breaker:

• Interrupts two hot wires simultaneously

• Supplies 240V

• Handles larger loads ( from 15A to 200A+).

• Used for dryers, ovens, HVAC units, and water heaters

• Occupies two panel slots

Common cables:

• 10/3 or 8/3 NM-B for 30–40A appliances

• 2-2-2-4 SER for feeding subpanels

• 8/3 MC cable or 8 AWG THHN in conduit for industrial or commercial applications.