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Wiring Lights in Series

If you are searching for answers on wiring lights in series, unless you are doing an experiment for a science project on electrical theory, you are most likely not using the correct terminology.  Wiring lights in series is not something that is done in normal practice, especially in home wiring.

If you are not looking for information about wiring lights in series, but rather wiring a series of lights together on one circuit, the way the lights are connected is a parallel arrangement, and not series.  Wiring lights in series results in the supply or source voltage being divided up among all the connected lights with the total voltage across the entire circuit being equal to the supply voltage.

For many reasons, in practice this type of series connection is not done.  Varying degree of lumen output from the connected lights, all below the intended rating of the fixture, and the fact that if one light burns out, the entire circuit quits working are among the most obvious reasons why.

So with the exception of rare circumstances, wiring lights in series is not done, and the connection is a parallel circuit.  Each fixture is connected to the hot conductor and the neutral conductor so that each fixture has the source voltage present.

One example of wiring lights in series was some Christmas light strings that used to be fairly common.  Again, the major negative drawback to these was when one bulb failed, the entire string quit working.  Short of checking each bulb with an ohm meter, the way of solving this was the tedious exercise of replacing each bulb, one at a time with a known good bulb until the string lit up again.

So the next time you hear someone discussing wiring lights in series, they most likely mean that they are wiring a series of lights, but connecting them in parallel.

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  • Songre

    Hi Peter I do need to wire two bulbs and a switch outlet in series can you help me? I did do one using one 75 watt and one 100watts but I am scared to connect it because I am not sure if I did it correctly….Here’s what I did I placed the power wire neutral(large Pin) on the silver screw on the outlet, then I place the hot on the Gold screw, now I broke the tab on the other side of the switch and connect two wires connecting the two light bulbs with socket jumping each other, but when I tried powering it up with a 9volt battery…note for safety only the second bulb turns off when I place a jumper in the receptacle. It is supposed to work together for load on a circuit. Can you help? Thanks….. 

  • Mandyboyd

    i’m having problems with new light fittings in my hallway, and shower room, took old fittings off, drew diagram of old wires, put up new fittings, re wired as was, lights work, but won’t switch off, can you help?

  • Rnaumann002300

    how do i wire a vent-a-hood with a fan, a light, 2 switches, and 1 power source?

    • Since the hood needs a seperate line, I recommend getting a gas powered generator. You could mount it under the hood to vent the fumes. Anywho… It doesn’t matter which way you run the wires, the electricity knows what to do, that is it’s job. The most crucial thing to remember, is whenever you cut into the insulation and the wires, keep the cut ends pointed up, or you will allow all of the electrons to run out onto the floor. Happy wiring!

  • Brooke

    I could figure my wiring situation out if i kept going to breaker box, but rather ask u guys;) so the wires coming from ceiling (2) are in black roping n appears tgat both are copper wires, as we’ll as my old chandelier I’d like to put replace there has 2 wires running threw chain in rubber plastic, I split them and sure enough there both copper, call me crazy but w/ out running around is there another way to tell black from white?? Just wiring from a one on/off switch


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