I am trying to install a new light fixture in a new condo.
In the fixture box, I can see wire nuts covering red, white, black,
blue and green wires.
It is normally to the white and black. But in this case one do I wire
my light fixture to? I live in Ontario.
Most likely white and one of the colors, except green. You need to connect a
test light to the white wire and each color,one at a time, to see which
other wire gives you voltage when the switch is turned on, and disconnects
voltage when the switch is turned off
Then it must be the red. The red is the only one with one wire,
suggesting that it is intended for this light fixture. I had connected
it to the red and white on another fixture. Thought I would ask just
to make sure. And what are the other colors anyway - the blues and
Black, red, and blue are all possible "hot" wires. White is always
neutral. Green is always ground. I'm not sure why you have a blue wire
in there; it's very rare to see three hot wires in a box. Perhaps this
is wired with the box always hot and a switch leg dropped down the wall,
and the blue wire is for possible future installation of a ceiling fan
controlled by a wall switch? Or someone has gotten fancy with the
wiring and you've got two phases in that box? (you can save a wire if
you're running a long run from the breaker box of two circuits by having
two "hots" on opposite phases; the neutral can then safely be shared
In any case, what I would do would be to simply take all the wire nuts
off, and test for voltage between the black and white, then red and
white, then blue and white and see which one is controlled by your wall
switch. The light fixture should be wired with the black wire of the
light to whichever of the three is appropriate, and white to white. If
you don't have a test light or multimeter, you could simply hang the
light fixture from the box with a piece of scrap wire, wire up the
neutral, and touch the black wire to the various potential hot wires to
see what works. Grasping the wires by the insulation, of course, not
the copper... (hey, some people need to have this mentioned to them.)
All of the above is ASSuming that wiring in Canuckia conforms to the
same codes and standards as it does here in the YooEss.
replace "fly" with "com" to reply.
I'm guessing this is THHN in conduit? Sounds like it is feeding another
circuit in the same area from an opposite phase. Does a white wire
leave the box in the same direction as the blue? Or you could just
measure voltage across black and blue to see; I'm guessing you'd find
240V instead of 120V (use a multimeter or 240V bulb for this; you don't
want to use a regular light bulb as a test light, it will blow almost
replace "fly" with "com" to reply.
You can not really safely assume much with house wiring. Code
specifies the white
is the neutral and the green is the ground, so that eliminates those
(but I'd still check
to make sure). You really must do as RBM said and test to see which
are controlled by the switch. If you can't test it safely then you
attempting to do electrical work.
If I was there, and had my tester, I could explain everything. But I
- what kind of switch or switches control this light
- how these wires are interconnected in the box
- how many lights are controlled by this switch.
As I said, testing safely is your best bet, as well as getting your
properly approved by the local authoritahs.
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