Need information on a switch replacement that turns on 2 lights simultaneously

Question

I have a switch that turns on 2 garage lights at the same time and I need to replace it.
The one that is installed has a plastic piece around it. Do I need to purchase the same kind or can I purchase one without the plastic casing?

Answer 1

Any standard switch (toggle like this, or Decora style but then you'll need a new faceplate) should be fine. Wire "the same as the old switch", but maybe not:

A simple switch of this type should have two wires attached to it, but it could have more.

• Hot (power in). Normally one wire, but possibly two in order to pass power on to another switch in this box or to another device elsewhere. If you have just one, connect it to a screw on the new switch. If you have two and they are connected with a pigtail then only one (the pigtail) is actually connected to the switch, and connect it to a screw on the new switch. If you have two and one is connected to a screw and the other is connected to a "backstab" ("push in connector", "Quickwire", etc.) then get a short piece of 12 AWG (15A or 20A circuit) or 14 AWG (15A circuit) black wire and use it as a pigtail to connect to the original two wires on one end (with a wire nut) and to the screw on the new switch. Never use backstabs.
• Switched Hot (power out) Normally one wire, even when controlling two lights. It is unusual but possible that you have two wires here for the two lights - far more common is that wires (switched hot and neutral) chain from the first light to the second light. Same rules as the hot wire - one to screw or two to pigtail to screw, never use backstab.
• Ground wire - if it is a metal box then ground wire is not needed. If it is a plastic box (or if you have an existing ground wire, so might as well connect it) there should be a matching ground screw (usually green) on any new switch.

On a standard switch there is no difference between "hot" and "switched hot" screws. On a smart switch there usually is a difference, but that would be a different question as other things are involved such as adding neutral to the switch.

Hot and switched hot should, nominally, be black, red or some other colors besides white or green. However, if you have an existing white wire on the old switch then you can still use it because old-style switch loops (normally white for hot, black for switched hot) are grandfathered, and you are only repairing the circuit, not adding a new circuit.

As noted in a comment, make sure to turn off power to everything in the box before working on this switch. It is possible to have multiple circuits breakers or fuses for different switches/receptacles/etc. in a single box, and they should all be turned off before working inside the box.

As far as the type of switch, if you're a contractor installing dozens (or more) of switches a day, I understand trying to cut down costs as much as possible. But for a homeowner replacing a few switches, spending a little extra to make things a little better is, in my opinion, money very well spent. Using Leviton from Home Depot as an example (no connection with either company), it is the difference between an 88 cent basic switch and 3.98 better quality switch. There are a bunch of differences, but the key one for me is that the more expensive switch lets you side wire with screw-to-clamp so you don't have the problems of a backstab but you get the convenience of not having to make a hook. (We see pictures all the time of hooks in the wrong direction, hooks with too much insulation removed, hooks with not enough insulation removed, etc.)