Mike Dolt Enterprises
Mike Dolt Enterprises
User: stevee, Location: Eastern Oregon
Asked on: Wednesday, April 27, 2011 at 2:47 pm EDT
Answered on: Tuesday, May 14, 2024 at 4:41 am EDT
Question: I've installed 12 HPS fixtures. They are fed from a 3-ph, 4-wire, 120/208v system. I've connected them on three circuits sharing a common neutral. There are 4 fixtures installed on each circuit and are connected at 120v.When I turn the lights on, all 12 fixtures individually cycle on and off. They don't all cycle on/off at the same time, they cycle randomly.The fixtures are all new, I don't think I've got 12 bad fixtures so I'm sure it's not the ballast and/or lamps.Any help would be appreciated.Thanks!
Possible Causes
Neutral Miswiring
Verify that the neutral wire is properly connected and not open or grounded.
Ground Fault
Check ground connections to ensure they are secure and continuous.
Circuit Overload
Ensure that each circuit is not overloaded by too many fixtures and that the wire size is appropriate.
Voltage Drop
Measure the voltage at each fixture to ensure it is within the operating range of the lamps and ballasts. Excessive voltage drop can cause unstable operation.
Electromagnetic Interference (EMI)
If there are other high-power electrical devices nearby, they could be causing EMI that interferes with the fixture ballasts.
Defective Components
Although unlikely, check if any of the ballasts, ignitors, or starters have failed.*
Lighting Controls
If there are any lighting controls installed, such as motion sensors or dimmers, they could be causing the issue.
Troubleshooting Steps
1.
Check Neutral Wiring
Confirm that the neutral wire is correctly connected on all circuits. Test with a voltmeter to ensure continuity.2.
Inspect Ground Connections
Make sure all ground connections at the fixtures, panels, and electrical boxes are secure and free of corrosion.3.
Verify Circuit Load
Measure the amperage draw of each circuit and compare it to the circuit breaker amperage. Ensure that the load is not excessive.4.
Measure Voltage Drop
Use a voltmeter to measure the voltage at the input of each fixture. Check for a minimum of 115V and a maximum of 125V.5.
Eliminate EMI
Try isolating the fixtures from other electrical devices to see if the issue persists.6.
Swap Components
If possible, try swapping out ballasts, ignitors, or starters to see if the problem follows the replaced component.7.
Check Lighting Controls
Disable or disconnect any lighting controls to determine if they are causing the issue.8.
Contact Manufacturer or Electrician: If all troubleshooting steps fail, contact the fixture manufacturer or a qualified electrician for further assistance. Flag for review