trouble with a three way switch...

ben ttech · Post by **ben ttech** » Mon Nov 09, 2009 4:20 pm

replaced the exterior end switch of a long two way...
and isolated it from the dimmer next to it,
[ ya, helping a diy finish a job ]
it was wired real odd, and there was a confusing junction box to boot ]

L - 3S - J - 3Shot - L

somehow, i now have low voltage at the end light, all connections are good, but i did re arrange the wires in the long run between switch and junction

screwy

ben ttech · Post by **ben ttech** » Mon Nov 09, 2009 9:00 pm

i juggled the wires in the long leg out to the distant bulb,
now the bulb is dim...

i think one of the wires on that run has high impedence, and was formerly the ground...

[ ive omitted ground in the diagram, bare copper changed to white in that junction box "_ ]

zem · Post by **zem** » Tue Nov 10, 2009 7:57 am

that diagram doesnt tell much, your explanation is not very clear i bet you're doin something wrong. careful not to cause a fire, try labeling every object and outlet in the diagram. why is the wiring so complex? try simplifying it it can be a wrong maybe a smaller wire this can cause a fire cuz the high voltage can burn the whole wire. i never had to use such complex multiple connections for running a light i just use a good source and a big wire to hold high voltage easily i ground it and get as many outlets as i need from that source

ben ttech · Post by **ben ttech** » Tue Nov 10, 2009 9:53 am

sorry, electrical shorthand,
there, i labeled the diagram...

the complexity is due to the nature of a 3way switch, that is a light which can be turned off or on from different switches at different locations, in this case the switch at the door turn on your porch light and another out at the parking spot at the street... out at the street is another switch which lets you turn those light off after you reach the street.

the trouble started when i replaced the switch and box at the street,
the lamp suddenly cannot fully illuminate the two bulbs in its fixture...
screw in the second and it comes on dim, and the first one dims to match.

i have impedience in a line that wasnt being used before,
ive no idea how to measure impedience, so i went and juggled through all the possible combinations of wires but it still is like that.
looks like the fix is going to be a single bulb light fixture

this was originally a homeowner instalation,
the drawback of how the cables are run means that one of the light fixtures will always have power, effectively the neutral to it is switched instead of the hot. not how id like to see it work but short of pulling more wire i can see a way around it, nor think thats the cause of the troubles.

it did work correctly before i replaced that switch and box, should have taken a picture of how it was wired for reference...
it was funky, i couldnt figure out how it worked as he had it originally

zem · Post by **zem** » Tue Nov 10, 2009 11:42 am

the wiring looks right ive done this with onelamp 2 switches in a room it worked just fine, it must be something in the switches or the new line as you figured. try changing the switches and the wires one at a time you should be able to know wats the problem. if it doesnt work then it beats me

ben ttech · Post by **ben ttech** » Tue Nov 10, 2009 3:52 pm

as shown,
the wiring determines that one fixture has hot coming through its socket properely, while the other is forced to reverse polarity in the same.

but polarity is for 12 volt weenies, it dont mean shit in residentual and basic commercial...

or does it???

i figured another option, will attempt and advise

ben ttech · Post by **ben ttech** » Wed Nov 11, 2009 9:39 pm

here is the configuration which solved the issue...
its uses the ground for neutral, and allows the match of the two lamps polarity...

ben ttech · Post by **ben ttech** » Thu Nov 12, 2009 11:42 am

the questions remains,
how the hell did this work AS previously wired?!?

he had a wire coming up to the 3ways switch, which looped through one of the screws [ dont recall which one ] and continued up to the light fixture...

ben ttech · Post by **ben ttech** » Tue Nov 17, 2009 12:21 am

DAMN!

now that we lost mclovin,
i guess were the only electricians left on the site zem...

i should have a card printed.

Post by **roller24** » Tue Nov 17, 2009 2:00 pm

That should have been one of 2 leads connected to the switch in a normal application.
Otherwise, there is nothing to switch.
the hot lead would have passed by the switch in that manner and traveled the fixture.
Another lead would have been on the opposite terminal also traveling to the fixture, and then back to the supply line.
when the switch is off, the electricity can't loop therefore not lighting. ON completes the cycle.

I've never seen a switch work with on lead on one terminal