Hardwired means there is no plug. The device is connected permanently into the building wiring, usually inside a junction box or the device's own terminal compartment, and disconnecting it is a job rather than a tug.
Why anything is hardwired
Three reasons, and most hardwired things have more than one. A plug and socket is a connection that can loosen, corrode or be pulled out, and for something that must not stop working — a smoke alarm — that is unacceptable. For something drawing heavy current continuously, a plug is also a heat risk at the contacts.
And some devices are simply not built with a cord, because they are meant to be part of the building rather than an appliance in it.
What it means for you
You cannot move it, and you cannot replace it yourself in most cases, because doing so means opening a connection to live building wiring. It also means the device has no on-off other than its breaker, which is why hardwired equipment usually sits on a circuit you can identify at the panel.
Where you meet it
Smoke and CO alarms on a modern circuit, most Level 2 EV chargers, built-in ovens and cooktops, furnaces and air handlers, and light fixtures. Anything interconnected — alarms that all sound together — is hardwired by necessity, because the interconnection is a third wire between them.
How to spot it in your house
- No plug and no cord entering a wall socket: the cable disappears into the wall or into a box behind the unit.
- A hardwired smoke alarm has a small connector and a cable running into the ceiling box, and usually a backup battery.
- If turning something off means finding its breaker rather than unplugging it, it is hardwired.
Related terms
- Level 2 chargerA 240-volt car charger, running off the same supply as an electric dryer, which adds range several times faster than a regular wall outlet.
- NEMA plugThe standard naming system for North American plug shapes. NEMA 14-50 is the big 240-volt socket most plug-in car chargers and ranges use.