ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

Topic Options
Rate This Topic
#60916 - 01/13/06 01:46 PM Electronic Ballast
Wireless Offline
Member
Registered: 06/09/05
Posts: 73
Loc: Los Angeles CA USA
Hi everyone. I have been having some problem with some 2x4 troffers. Customer called last week a bunch of fixtures are out I changed 6 of the ballasts. a few days later they tell me the breaker keeps tripping so I put my amp meter on it it was pulling 24a so I split the circuits instead of 2 circuits now there are 4 for all the lights. I come this morning I see 2 ballasts are out one is one I just changed. What am i looking for?
Top
Work Gear for Electricians and the Trades
#60917 - 01/13/06 02:00 PM Re: Electronic Ballast
mxslick Offline
Member
Registered: 10/24/04
Posts: 803
Loc: Atomic City, ID USA
Need more information to really help..how many fixtures were on each circuit, is the panel serving them 3 phase, were the circuits sharing a neutral?

Shared neutrals are a big no-no with ballasts, especially electronic ones. Harmonic currents add up rapidly and cause no end of problems and repeated ballast failures.

And any loose connections can kill e-ballasts rapidly. Had one case personally where we went through 3 ballasts on the same fixture until I pulled on the whip and the loose wirenut fell off in ther j-box. Fixed that and no more failures since (about 6 years now.)
_________________________
Stupid should be painful.
Top
#60918 - 01/13/06 02:29 PM Re: Electronic Ballast
Wireless Offline
Member
Registered: 06/09/05
Posts: 73
Loc: Los Angeles CA USA
about 20 lights per circuit. single phase service. lights are fed from a 3 wire circuit.
Top
#60919 - 01/13/06 02:40 PM Re: Electronic Ballast
ShockMe77 Offline
Member
Registered: 06/11/05
Posts: 821
Loc: Rahway, New Jersey
That shared neutral is doing twice the work of either of the ungrounded conductors. IMO you need to install a dedicated circuit and split up the fluorescent lighting.

Good luck!
Top
#60920 - 01/13/06 04:06 PM Re: Electronic Ballast
wa2ise Offline
Member
Registered: 11/29/02
Posts: 782
Loc: Oradell NJ USA
Quote:
single phase service

That shared neutral is doing twice the work of either of the ungrounded conductors.


If it's single phase (pair of 120Vs 180 degrees out of phase) electronic ballasts on both sides should be drawing their spikes of current at the same time (in respect to the timing of a 60 cycle waveform) and thus the neutral should be sharing/splitting the spikes the same way it would if the loads were just resistors. When you get neutral overload is when you have multiple phases, 120 degrees out of phase. Then the loads on phase A draw their spikes of current at a different time then those of phase B.

A bad connection on a neutral could cause problems like those you normally see with neutrals serving other kinds of loads.

[This message has been edited by wa2ise (edited 01-13-2006).]
Top
#60921 - 01/13/06 04:54 PM Re: Electronic Ballast
trekkie76 Offline
Member
Registered: 06/19/04
Posts: 220
Loc: baileyville, maine, usa
20 ballasts per circuit? check the amount of current each is pullin, it can add up. As long as they are not on the same phase, the neutral in the 3wire circuit should only have the imbalance on it, if they are on the same phase, the current in the neutral will be the sum of the current on both phases.
Top
#60922 - 01/13/06 07:51 PM Re: Electronic Ballast
waymag Offline
Member
Registered: 01/13/02
Posts: 67
Loc: dallas, texas, USA
Are the right lamps being used. Maybe too high a wattage for the ballast.
Top

Member Spotlight
Member Since: 12/24/00
Posts: 4259
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
0 registered (), 55 Guests and 9 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 47
HotLine1 43
gfretwell 19
Ruben Rocha 12
Trumpy 9
 
Newest Members
Scotto, Freecrowder, clee512, Jdscott2005, FAIZAN

ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals