Single-Pole vs. Double-Pole Switch: What’s the Difference?
Spark your knowledge of these two electrical components
Highlights
Single-pole switches are commonly used for lighting and low-power appliances.
Double-pole switches are primarily used in industrial settings but can serve as safety switches for large 240-volt home appliances.
Single-pole switches have two terminals, while double-pole switches have four terminals.
Double-pole switches can handle higher power loads than single-pole switches.
Whether planning a new switch installation or growing your knowledge of electrical components, you may have encountered the terms single-pole vs. double-pole switch. But what do they mean? A “pole” is the number of individual circuits a switch can operate: A single-pole switch can control one circuit, while a double-pole switch can control two circuits. Still, that’s only scratching the surface of what distinguishes the two types of switches. Let’s dive into the differences between a single-pole and a double-pole switch.
What Are the Differences Between Single-Pole and Double-Pole Switches?
| Type of Difference | Single-Pole Switch | Double-Pole Switch |
|---|---|---|
| Number of Circuits Controlled | One circuit | Two circuits |
| Uses | Common light switch | Isolates appliances |
| Power Capacity | 15–20 amps | 30–40 amps |
| Number of Terminals | Two | Four |
| Cost | Costs less | More expensive |
Single-Pole vs. Double-Pole Switch Uses
A single-pole switch is the most common type of electrical switch in residential homes. These are typically used for lights and small appliances that don’t require a 240-volt outlet. Double-pole switches are often used in commercial settings and large machines. You’ll also find them in homes as a safety shut-off feature for large 240-volt appliances, such as an air conditioner, electric furnace, or water heaters. Don’t confuse these switches with a three-way switch, which allows you to control a single fixture from two locations.
Power Capacity Differences
Double-pole switches can handle more power, around 30 or 40 amps, compared to regular switches that handle 15 or 20 amps. Double-pole switches also have a green screw that you use to connect the grounding wire in the electrical system for safety. Contact a local electrician to install both types of switches for best results.
Number of Terminal Differences
A single-pole switch typically has two terminals, while a double-pole switch has four. The two terminals on a single-pole switch are used for the hot and the switched hot wires. In contrast, a double-pole switch has four terminals to control two separate circuits or hot wires. These extra terminals allow it to fully disconnect both hot wires in the circuit when turned off, making it the most suitable for high-power appliances requiring a double disconnection for added safety.
Cost Differences
The cost of installing a light switch between a single-pole vs. double-pole switch can vary based on factors such as the brand and quality of the product. Generally, single-pole switches are more common and more affordable than double-pole switches. Single-pole switches typically cost $1 to $10 each, and double-pole switch prices range from $10 to $30 each.
Cost to Install a Light Switch
The cost to professionally install a light switch generally ranges from $60-$300
influenced by factors such as the type of switch, labor costs, and potential rewiring needs.
Switch Type
Basic "plug and play" switches are the least expensive. However, dimmer switches, timers, smart switches, and three- or four-way switches typically incur higher costs.
Labor Costs
Electricians in urban areas often charge more per hour than rural ones. Additionally, difficult-to-access sites may result in higher fees. Remember, the typical labor cost ranges from $50 to $100 per hour on top of paying for the switch.
Rewiring Costs
Installing a new fixture and switch, especially if rewiring is needed, can take several hours and exceed $400. Grounding a two-pronged outlet, for example, can be exceptionally costly.
DIY vs. Hiring a Pro
Installing single-pole and double-pole switches yourself can save money and be rewarding. With basic electrical knowledge, single-pole switches are straightforward to install, as they handle lower voltages.
Double-pole switches, rated for higher currents, are commonly used in industrial spaces. While the wiring is similar to single-pole switches, you'll work with thicker wires and higher currents, which involves more risk.
In both cases, hiring a professional ensures safe, compliant installation. Electricians have the expertise to handle complexities and troubleshoot issues, ensuring proper switch function. Though more costly, professional installation is worth it for your safety and your home's security.
Frequently Asked Questions
You can determine whether you have a double-pole switch by examining its wiring. Unlike single-pole switches, which have two brass-colored terminals, double-pole switches feature four. These switches are typically only found near high-powered appliances such as electric furnaces or water heaters. If you’re unsure what type of switch you have, contact a local electrician to confirm.
You can use a double-pole switch for a regular light fixture, but it's unnecessary and won’t be the most efficient choice. A single-pole switch works perfectly for standard lights. Double-pole handle high-power appliances that require both hot wires to be disconnected. Using a single-pole switch for regular lights is more cost-effective, simpler, and more common in residential settings.
Not necessarily. A DIY light switch installation for both types follows similar steps, but double-pole switches have extra terminals for the second circuit. If you're comfortable with single-pole switches, you should be able to tackle double-pole switches with some additional wiring knowledge. In any case, it’s essential to follow safety guidelines and follow the manufacturer’s installation instructions for your specific switch model.