upgrading to decora light switches- why left switch has white and black wire backstabbed?

Question

I have a 1979 home; I'm looking to replace 2 light switches in my bedroom from toggle style to decora-style.

I would like to double-check some things before starting and any help is much appreciated as I'm a novice, but learning quickly.

There are pictures as well, but here is the wiring setup from what I can see:

2 single-pole toggle switches - the left controls the only light fixture, and the right switch simply controls an outlet.

There are 4 cables in the junction box, described below:

1. Cable 1: 14/2 (left hole of the junction box)

• white is connected to wire nut #1 w/ white cap
• black is connected to wire nut #2 w/ red cap (nut is attached a) backstab of left side of right switch, and b) backstab of right side of left switch)
• ground is connected to wire nut #3 (and attached to both left and right switch ground terminals)

2. Cable 2: 14/2 (also left hole of the junction box)

• white is backstabbed into left side of left switch
• black is connected to wire nut #2 w/ red cap
• ground is connected to wire nut #3

3. Cable 3: 14/2: (middle hole of junction box)

• white is connected to wire nut #1 w/ white cap
• black is connected to wire nut #2 w/ red cap -ground is connected to wire nut #3

4. Cable 4: 14/2 (right hole of junction box)

• white is connected to wire nut #1 w/ white cap
• black is backstabbed into right side of right switch
• ground is connected to wire nut #3

^ might not be 100% I have the above correct as there's lots of wires in the box, but Ive reviewed it several times as best I can.

(Side note: if there is a free modeling tool that lets me create a visual wiring diagram and that's easier than pictures or the above text descriptions, please let me know! )

My [novice] interpretation of this wiring setup is that the left switch, because it has 1 white and 1 black attached, could be a 'switch loop' . The right switch, because it has 2 blacks, one is hot coming in, and the other is a hot going out- probably to the outlet that it controls.

Arriving at my question, if you see the pictures below, am I correct to simply 'preserve' this setup by attaching the left switch's white and black wire into my new decora switch's 2 brass terminals, then attach the ground of course. If indeed it's a switch loop, maybe put black electric tape around the white wire to indicate its a 'hot' ? Finally, attach the 2 black wire's into the other new decora switch on the right, and ground? (power off 1st, ofc)

Thank you very much! 4 cables was a lot to interpret on my own :)

Pictures:

Answer 1

It's great that you have pictures prior to taking everything apart.

To make this simple be concerned only with the individual wires attached to the switches. Be sure the breaker to both switches is off.

You appear to have enough wire, so cut the wires right up against the switches BUT one at a time.

Strip the insulation from the wire and make a hook. ( you will need about 1/2 inch of bare wire)

Place the wire behind the screw on the new switch and tighten the screw tight enough so there is no movement under the screw from the wire. Open end of the hook to your right so as you tighten the screw it will not force the hook open. If your hook is too big close it a little with needle nose pliers. ( there is a torque spec, but I doubt you would have the tool for that) Just be sure it is tight.

Place the wire on the corresponding screw that the wire was on from the old switch. ( on simple single pole switches it doesn't really matter upper or lower, but let's keep it simple)

The bare ground wires go on the green screw. Carefully bend the wires to go back in the box and attach the switches, but allow them to move a little so you can align them with the openings in the switch cover.

Install the cover.

turn the breaker back on.

There you are done!

(I know this may have been more detail than you need , however I have been chastised in the past for not providing enough details, even when it was apparent that the poster knew what they were doing.)

Answer 2

A switch loop would have black and white to the same cable, so it's not a switch loop. The white wire has no business being on this switch.

I suspect the last guy cheated. They only had /2 from switch to light, but wanted to extend the circuit off the lamp. So they rearranged things, making black always-hot, white switched-hot, and for neutral they illegally converted the ground wire to neutral. Aside from that being dangerous on its face, they also kept that cable's ground wires with the grounds.

When you try to use a ground wire as neutral also, it isn't ground anymore. It's neutral. So now all metal things in the circuit are attached to neutral. If that wire has a problem, they can be energized at 120V -- that's the reason we insulate the neutral wire.

So I would open up the lamp boxes and take a look at the wiring. If that has been done, then I'd think hard on how to eliminate it. Most extensions are optional for some thing the prior owner wanted, so maybe it can simply be removed.

Answer 3

Re why a switch might be connected between white and black: In the US, this may be a "switch loop", where a cable containing black and white came down from the fixture to the switch and white is being used to return the switched power. If so, proper practice would be to have colored the end of the white wire black or red with marker or tape to indicate that it is being used as switched hot rather than as neutral... but, especially on amateur installs, that doesn't always happen.

Neutral must be white, but white is not always neutral.