You can control just about anything with a Raspberry Pi, even high-current mains voltage devices like lamps, toasters, coffee makers, or just about anything you can think of! In order to do so in a safe manner, it’s important that you use a quality relay that’s properly rated for the task, and is ideally optoisolated from the Pi. The Appliance HAT Mini does precisely this, with a pair of beefy relays on a standard HAT.
The included relays are rated for 16A @ 250VAC, meaning they can be safely used anywhere in the world, even with fairly beefy loads. Just keep in mind that loads with large motors (drills, air conditioners, compressors) have a large inductance and can generate voltage spikes way beyond what the relays are designed for, potentially damaging or welding the contacts. If you want to control something that powerful, look into adding a high-power diode and snubber network that can handle the back EMF generated when switching the load.
These relays use integrated spade connectors, making it easy to get a solid connection and reducing ohmic losses. They’re also optoisolated, meaning the Pi Zero and the MCP23016 that’s used to switch them aren’t electrically connected — there’s an air gap inside the optoisolator. This is good practice, and we’re happy to see it implemented here!
So if you have a project idea where you need to switch a large load, make sure to check out the product page and use a device like this that’s built to handle it safely. It even has a 12 month warranty!