Welcome to another episode of CircuitBread practicals where we talk a little bit more
about that intersection between electrical engineering and electrician work. And, frankly,
more of just how to do electrician work from the viewpoint of an electrical engineer. Today, I want
to talk about how to wire a switch, which has got to be one of the most simple things that you can
possibly do when you are working on the electrical in your house. So, first of all, this is something
that I probably should mention all the time but if you're gonna work on anything electrical,
either 1) know what you're doing or 2) disconnect all of the wire and double
check and make sure that your multimeter is set for AC when checking and all that sort of stuff.
Because you do not want to hurt yourself and if all else goes poorly, just get an electrician
even though this is simple enough that almost anybody should be able to do.
Unlike an outlet, all a switch needs is to interrupt one thing that is flowing,
basically from your wall to your light or whatever it happens to be.
Now, the most interesting portion is what happens in the box itself. If you're just doing a
replacement of something that's already in there, it's pretty straightforward, but like in this
case, you can see there's actually a lot going on. This is not the simplest box and we debated
actually finding a different one that would be a little bit more straightforward. But in here,
we actually have several circuits coming in and going out. Power to our smoke detectors actually
comes from this circuit for the entire house and so because of that we didn't want that to
be attached to the switch, we just put the power all together. So on this hot line, I basically
took the two coming in and made a pigtail right here and then on the neutral, since we wanted
all the neutrals connected, we just put them all together because we don't need to worry about that
in the slightest. However, for the ground, since we had three wires coming in and we only have one
switch that needs to be grounded right here, we did something and I'm forgetting the word for
this but basically you put this little thing on there, you crimp the heck out of it, twist it,
and then it is all grounded together but you still have your one ground that you can use. Now, all we
are doing is taking the power that is coming in and putting a switch between it and the light.
Now, notice we are doing this on the hot line. If you were to do it on the neutral line, you
would flip the switch and it would turn off the lights but then the light itself would still be
hot. It would be a floating voltage which you want to avoid so whenever possible, which I can't think
of why it wouldn't be possible, you will want to put your switch in here in the hot line.
So let's just grab my strippers and really we don't need even my little tag anymore
and we will strip this off. If you watched our ampacity video, you can guess that this is 14
gauge wire because this is only a 15 amp circuit. We calculated that even with all of the lights
on this floor on, we'd only be using about 300 watts which is not very much. Now, I put
that away but I need to bring it back. We do have here and we can use these little holes right here
to shove the wire in, you just shove it in and then it doesn't pull back out unless you stick a
small thing either from a multi-tool or whatever in there. That releases it and then you can pull
it back out. My experience, and the experience of electricians I've talked to, those have a tendency
to fail and that does not sound like a good idea to me. It's actually recommended that if you can,
again, unless you're in a huge hurry I don't know why you wouldn't, you just want to put them in
and then stick them in like right there. It's a little bit of a pain at first as you get the
hang of it. It seems straightforward and maybe it is straightforward for competent people but,
for some reason it took me a while to make it so that I could do it consistently
and not be fighting it horribly. Okay, so that's pretty good, that's pretty good,
we can do more rigorous testing if we'd like but we're in a bit of a hurry
just so this video doesn't get too long. You will want to make sure that it's right side
up. This is actually branded on the bottom. That's one reason why I'm not going to use
any of these switches because I hate it when people brand their stuff unnecessarily.
So up here we have the ground. Now again, as I've talked about ground in some other videos,
you can see it is connected to the chassis. With the ground connected to the chassis,
if this does come loose for any reason and it's flopping around in there and it touches this,
instead of electrifying everything and you getting zapped when you touch the switch,
it's sending it back via the ground it's going to create a short circuit and it's going to pop the
breaker which is exactly what you would want to do in that situation because then you'd be like hey
something's wrong here instead of hey I'm dead that wasn't cool. I don't want that to happen. So,
always make sure you are grounding your stuff for safety reasons and again green for ground
or bare copper and the wire itself and as always, reminder, that ground in this case
is just for safety. As electrical engineers we would look at the neutral as our ground line and
then this is just there to make it so if things go poorly, it's less likely that we will die.
Okay, so now that it's all in there, you can just take this and kind of bend and tuck and
that's where you want to have enough wire that you can work on it nicely when you pull it out
but also not so much wire that you can't cause it to go back in. So you have this screw right here
and this screw down here and they are just going to go in those holes and as they go in, these
two tabs are gonna catch on the drywall since we actually have drywall for this example and it's
going to hopefully be nice and tight and flat and since there's a little bit of wiggle room back and
forth, there we go, there's the wiggle room, if you find out you've installed it a bit like that,
you can actually loosen a bit and straighten it and then suck it down nice and tight and that will
make it look nice and you don't want these wobbly because nobody wants to go like this and feel the
entire thing shake because that would I don't know about you but that would make me feel weird.
Okay, I'm not going to waste my time putting that in. I would usually have a power tool to do that.
Just make it a lot easier than me trying to do it by hand. And that's it! Hopefully this was
very straightforward and helpful in showing you how to swap out a switch. If you liked the video
please give it a like and if you'd like to learn more about these practical electrical engineering
and electrician combos, please subscribe to our YouTube channel and we will be getting very soon
back to the electronics and all of the fun stuff that we love as electrical engineers.
In the meantime, hope you have a great one. We will catch you in the next one.