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

Higgins, Martha E mehiggins at wm.edu
Wed Sep 30 18:46:11 PDT 2015

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.


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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

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