Dumb Electrical Question - Wiring

macneill

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I picked up two round flourescent lights on my street that someone was throwing out. I'm assuming they work...

Going to wire them into a circuit with an exisiting 6' flourescent in my shop.

I'd always assumed black was negative.

Last night my buddy tells me different that white is actually hot.

So which one is hot and does it matter since it's AC?

I don't know much about electrical stuff.
 
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by the way...it's not a dumb question. what would be dumb would be not asking and getting your butt fried.

make sure u turn off the power to the circuit....don't rely on the light switch. it could be "wired hot", meaning that the neutral wire is switched instead of the hot leg, allowing the light to turn off but there to still be power in the line.
 

LandCruiserPhil

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The electrical code allows the "white" wire to be used as a power conductor in a residential switching application. So dont assume the "white" is always netural.
 
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I've been wiring 110 volts w/ white and black being the hot ones and green being neutral. Everything has been working fine.
Yeah, and that's usually fine...but there are times when a white wire can be hot...when working on things try to understand the circuit, and then it will make more sense how things are hooked up...just connecting like colors is correct sometimes...sometimes it is definetly not correct.

:cheers:
 
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I've been wiring 110 volts w/ white and black being the hot ones and green being neutral. Everything has been working fine.

THis is wrong.

Do you have picture of a plug or other device showing what you did?


The white book is decent for general house wiring stuff, and the yellow one is quite good, but is not a 'how to' type book.
wiring books.JPG
 
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Joined
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I've been wiring 110 volts w/ white and black being the hot ones and green being neutral. Everything has been working fine.

actually, only one is hot (should be black)...the other(white) is neutral and the green is ground.

think of it as a race track...power should only go one direction.
the way it's supposed to work is:
power leaves the circuit breaker down the black wire to your switch. black wire on either side of the switch goes through your light/appliance and powers it. exits appliance through the white wire and back to breaker box....to ground.
to test this, try putting one leg of a circuit tester in the smaller hole of an outlet and the other in the ground hole....it should light up.
now, keeping one leg in the ground hole, put the other in the larger hole in the outlet. you'll see that it doesn't light up...because this is the neutral leg (hopefully attached to the white wire).
the way a light switch is supposed to be wired is this:
black(hot) wire into the switch box from fuse panel is attached to one leg of switch. black wire going out to light is attached the other leg of the switch. neutral wires (white) are wire nutted together. green wires are wire nutted together. this way there is no power in the light when the switch is off...normal wiring.
wiring hot means that the hot(black) legs are wired together and the neutral (white) wires go through the switch. they do this if the circuit also powers something other than the light and it needs power when the light is off....so it's always hot.
that's why u NEVER trust a switch when ur doing wiring. ALWAYS use a test light ($3 at home depot) before u touch bare wires.
 
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ar2stp48

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X2 on the Greenlee tester. It is only about $11 and works great; get it near a hot wire and it beeps. It is sensitive enough that you can determine which side of 12-2 wire has the black/hot wire. I do not go near wiring projects without this tool.

One common use of white as the "hot" wire in house wiring is the switch leg where a length of 12-2 is the drop. Black is hot into switch and white is hot out of the switch.

Code for wiring has not always been followed. I can remember years ago being told by a "handyman" that black or white didnt matter---scary. That was about the same vintage as the outlets without the ground--green--wire.
 

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