[PW] How is a 277 Volt Lighting System Wired in Series to Turn On a Large Group of Fluorescent Light Fixtures Wired in Series?

Mike Hindin mike.hindin at gmail.com
Mon Oct 5 14:36:55 PDT 2015


Standard home or industrial light fixtures are wired in parallel regardless
if they are 115, 230 or three phase 277 volt system.  See national
electrical code.  The circut breaker or a switch interrupts "hot" wires but
not the white neutral wire. In 115 volt circuits (standard US home,
offices, etc) there is one white neutral and one colored hot wire which can
have switches. 230 volt systems (US) which have two colored "hot" wires and
1 white neutral are used for home ovens, clothes dryers and industrial
machinery. Circuit breakers and switches in 230 volt systems connect or
disconnect both colored "hot" wires simultaneously. Power enters US homes
at 230 volts and is split to feed 115 volt circuits. 277 lighting circuits
have 3 colored "hot" wires.
Series wiring is not used because the voltage drop across 2 fixtures would
be 1/2 the line voltage and 50 fixtures would have 1/50th voltage!  Also
like old Christmas tree lights, one failure would disable all of the lights
in a series system.

Michael N Hindin, MPH
St Louis Park, MN 55426

On Sep 30, 2015 8:46 PM, "Higgins, Martha E" <mehiggins at wm.edu> wrote:

>
>
> The supply voltage is daisy chained from ballast to ballast. Most ballast
> can can accommodate two to four bulbs. Depending on the ballast type it can
> accommodate one to four different supply voltages, 120V, 208V, 240V or 277V
> single phase. Therefore there will be up to three unused capped leads for
> the different supply voltage options not being used.
>
> So the only thing that can be considered in "series" would be the supply
> voltage going from ballast to ballast. Therefore one switch can turn on/off
> as many fixtures that are being supplied by the supply voltage circuit.
>
> Martha
>
>
> Sent from my iPad
>
>
>
> Begin forwarded message:
>
> From: Sam Shipley <sams at dcpl.info<mailto:sams at dcpl.info>>
> Date: September 30, 2015 at 3:29:51 PM EDT
> To: "list at project-wombat.org<mailto:list at project-wombat.org>" <
> list at project-wombat.org<mailto:list at project-wombat.org>>
> Subject: [PW] ?How is a 277 Volt Lighting System Wired in Series to Turn
> On a Large Group of Fluorescent Light Fixtures Wired in Series?
> Reply-To: <list at project-wombat.org<mailto:list at project-wombat.org>>
>
> I have a rather lengthy technical electronics question to submit for a
> patron.  Please see below:
>
>     "How is a 277 volt lighting system wired in series to turn on a large
> group of fluorescent light fixtures wired in series?  One switch turns on
> around 50 fixtures at once.   I want to understand this from the breaker to
> the last fixture.
>     When changing out the ballast in a fixture, there are some wires that
> are not needed, that the electrician has removed and capped.  This process
> is similar to a 120 volt system, but has more wires in the 277 volt system
> that (I think) remain hot.
>      I have tried to find the information by searching the internet, using
> the keywords Fulham Ballast Co. Inc.   I also search the "How Things Work"
> web site."
>
>
> Thanks for any help you can provide.
>
> Sam Shipley
> Reference Librarian
> Dodge City Public Library
> Dodge City, Kansas
> sams at dcpl.info<mailto:sams at dcpl.info><mailto:sams at dcpl.info>
> (620) 225-0248, x201
>
>
>
>
>
> _______________________________________________
> Project Wombat - Project-Wombat-Open
> list at project-wombat.org<mailto:list at project-wombat.org>
> http://www.project-wombat.org/
> _______________________________________________
> Project Wombat - Project-Wombat-Open
> list at project-wombat.org
> http://www.project-wombat.org/
>


More information about the Project-Wombat-Open mailing list