YAET: What happens if you wire a light in backwards?

[dderidex]

So, wiring speakers all day and I'm cruising a long. Getting dusk-y outside, and have an outside light fixture to replace, so I just right to it and start taking the old one apart without even really thinking about it.

Go to put the new one up, have the black and white wires in my fingers, and...

Uhhhh.....

CRAP.

Both wires in the box are grey! Same exact type of wire on each!! So...errr...take a best guess from trying to recall which of the twist connectors I pulled the black and white wire from out of the original fixture, and...

Seems like everything works? I mean, light comes on and all. So....is this okay? Would it have blown the bulb or something if I'd wired it backwards? Would it have not come on? Or, would it look and work fine....and someday down the road...burn down the house or something.

 

[EyeMWing]

For AC, it doesn't really matter much, if at all. For DC, you'll blow some things up (but not lightbulbs)

 

[shoRunner]

it sucks in light....it becomes the anti-light

 

[Zenmervolt]

First, AC is not directional. Second, even with DC, a light bulb doesn't care.

ZV

 

[dowxp]

Just wondering, why would it matter? A light is just a resistor, not an active device really ...

 

[dderidex]

Originally posted by: EyeMWing
For AC, it doesn't really matter much, if at all. For DC, you'll blow some things up (but not lightbulbs)

Groovy. House wiring, so AC obviously. Wired the ground wire down, anyway, so I'd not expect anything TOO horrible to happen. Still...wanted to double-check. (I'm pretty sure I guessed right, anyway)

 

[dderidex]

Originally posted by: dowxp
Just wondering, why would it matter? A light is just a resistor, not an active device really ...

Hell if I know, I'm a computer geek, not an electrician! Software questions on my side of the building, hardware questions on the other side.

(Alright, not that bad, really, but I AM solidy in the "knows enough to be dangerous" camp with anything electrical, and just wanted to be sure! And, hey, if it didn't matter at ALL, why would they color-code the light fixture lines to begin with?)

 

[dowxp]

Well, not all devices in your house are simple loads, some may be reactive or inductive and must be wired in a certain configuration. Nevertheless, wiring of a lightbulb should not matter (except for the ground if there is one).

btw, i'm not an electrician -- just a newb EE, so this is all just newb "IIRC"

 

[Engineer]

The bulb becomes a super invertion of nature and absorbs all light instead of emitting it. Esentially, a portable black hole generator! :laugh: :shocked:

LOL...nothing (except regular light) unless the socket is grounded at which time the hot leg would be to ground causing the breaker to kick.

 

[dderidex]

Originally posted by: Engineer
LOL...nothing (except regular light) unless the socket is grounded at which time the hot leg would be to ground causing the breaker to kick.

Well, I did ground it (at least, TO the box, anyway - gods only know if that's grounded at all), and the breaker did not trip, so....feeling lucky!

 

[Engineer]

Originally posted by: dderidex

Originally posted by: Engineer
LOL...nothing (except regular light) unless the socket is grounded at which time the hot leg would be to ground causing the breaker to kick.

Well, I did ground it (at least, TO the box, anyway - gods only know if that's grounded at all), and the breaker did not trip, so....feeling lucky!

You gounded the fixture itself, not the socket (which wouldn't be grounded anyway that I know of). You'll be fine. Just remember that the side of the socket is hot now, not the bottom tip. If you touch the metal side of the bulb while screwing in (especially while touching the grounded fixture), it will shock the piss out of you! :Q

 

[MWink]

I'm not sure this is 100% correct but from what I've read the whole reason outlets in the US are polarized is for the safety of incandescent light fixtures. The connection in the bottom of the socket is supposed to be hot and the sides are supposed to be neutral. It's supposed to prevent people from getting shocked as easily. However as I understand it, from an electrical standpoint it won't cause a problem. The light should work either way.

 

[Pepsi90919]

Originally posted by: Zenmervolt
First, AC is not directional. Second, even with DC, a light bulb doesn't care.

ZV

LEDs will.

 

[dowxp]

Originally posted by: Pepsi90919

Originally posted by: Zenmervolt
First, AC is not directional. Second, even with DC, a light bulb doesn't care.

ZV

LEDs will.

an LED is not a resistor, but usually a PN junction ..