I don't know house stuff, please help!

I want to replace the light switch (this is just a generic "up is on, down is off" switch) in the garage with an automatic sensor. 

But I'm reading lots of stuff about 2 and 3 pole switches. And that if you pull the cover and it's 2, you'll need to run a neutral for the automatic switch. But I could have sworn the other day I read something about some 2 pole switches that are available, and of course, now can't find it.

I have no problem replacing stuff like (turn off breaker, etc, just like when I had to replace the wall switch and circuit board in my garage door opener), but I'd like to know what to order before I actually drop $30 on one of these. 

I would pull the cover and post a pic here so that we can see what you’ve got instead of speculating. 

My knowledge is somewhat basic, but my understanding is that the motion sensing electronics need some sort of power to run.  In AC systems you need hot and neutral to do stuff.  The lights themselves will have both but the switch will only be on the hot since you only need to break one side.  In older homes, they didn't run grounds all over the place so the light switch box would only have a hot wire and nothing else - unless for some reason they had also run a neutral to that box.  Newer installations have to have a ground, so some of the switches that have electronics in them will simply use the ground to complete the circuit.  So in a newer home (and by newer, I think I'm talking about something like three decades here) you want something that will work off of just a ground and a hot.  If it's older, then you've got to find a way to get power to the switch which will involve finding a neutral.  I think there are some motion control systems that are battery operated, but I'm not completely sure about that.

Poles, though, are something else, I thought.  If you have a single pole switch, that means that you've got one circuit that the switch powers.  Double pole means there are two completely separate circuits controlled by the same switch.  I think that's how they enable the wizardry that is the three-way switch, but I'm not 100% sure about that.

glueguy said:

I would pull the cover and post a pic here so that we can see what you’ve got instead of speculating. 

Good idea, I'm only doing a half-day in the office today, so I'll do it after lunch.

wae said:

My knowledge is somewhat basic, but my understanding is that the motion sensing electronics need some sort of power to run.  In AC systems you need hot and neutral to do stuff.  The lights themselves will have both but the switch will only be on the hot since you only need to break one side.  In older homes, they didn't run grounds all over the place so the light switch box would only have a hot wire and nothing else - unless for some reason they had also run a neutral to that box.  Newer installations have to have a ground, so some of the switches that have electronics in them will simply use the ground to complete the circuit.  So in a newer home (and by newer, I think I'm talking about something like three decades here) you want something that will work off of just a ground and a hot.  If it's older, then you've got to find a way to get power to the switch which will involve finding a neutral.  I think there are some motion control systems that are battery operated, but I'm not completely sure about that.

Poles, though, are something else, I thought.  If you have a single pole switch, that means that you've got one circuit that the switch powers.  Double pole means there are two completely separate circuits controlled by the same switch.  I think that's how they enable the wizardry that is the three-way switch, but I'm not 100% sure about that.

Home was built in 1984, so right on the edge of your 3 decade idea. 

In reply to z31maniac :

My parents 70s built house was totally grounded around the house- I bet you will find a grounded system.

Out 20's era house, on the other hand....

alfadriver said:

In reply to z31maniac :

My parents 70s built house was totally grounded around the house- I bet you will find a grounded system.

Out 20's era house, on the other hand....

Yeah, the house I grew up in was built in 1919. 

Still going strong on the original knob and tube wiring 100 years later.

A normal on-off switch is single pole, will have ON and OFF on the toggle itself, and only the hot is broken by the switch.

Some motion sensor switches use a neutral, some don't. 

You should have a neutral (white) wire in the wall box, but it will just be wire-nutted together since only the hot (black) is broken for a normal on-off switch. The light socket/fixture itself will use hot+neutral+ground. The switch should be grounded.

Pictures will definitely help. 

The switch could be on the lead feeding the circuit, in the middle of the loop, or at the end and that will change what leads you’ll have available. 

There are only two poles, North and South.  Don't let those Flat Earth weirdos try to tell you there are three. 

Please never assume a wire’s insulation color denotes it’s actual usage.  Always verify.

For example where I live, it is perfectly acceptable to have one two conductor romex feed a single pole switch- a black wire as a feed, the white wire as the switched hot.

Occupancy sensors can be gotten with or without a neutral, it seems to depend on the manufacturer.

paranoid_android said:

Please never assume a wire’s insulation color denotes it’s actual usage.  Always verify.

For example where I live, it is perfectly acceptable to have one two conductor romex feed a single pole switch- a black wire as a feed, the white wire as the switched hot.

I completely agree with the first sentence. Never assume.

I completely disagree with the second. Because reasons. Mainly death.

Turn the power off before you work on it