Voltage levels for Commercial building

[Hileg]

I am having to change incandescent lamps out in our lobby about once week. I've considered replacing them with flourescent bulbs but don't want to remove my flags until I understand what is going on and why these bulbs are prematurly burning out.These are bulbs rated at 120 volts single phase. The system is a wye 120/208 3 phase system. The voltage readings at peak load are 124.3/216.7 volts. Does this reading seem to high? What are the +/- voltage limits for this configuration? We have checked all the panels for loose nuetrals and bad connections and everything looks good. Any suggestions would be appreciated.

Thanks

 

[waross]

It sounds like your supply transformers are set one or two taps too high. The standard is 120/208.
If your supply has a lot of voltage fluctuation the taps are sometimes set high so that the motors have adequate voltage when the supply dips. The other side of the compromise is that when the supply voltage is up, your lights high voltage.
If your supply voltage is stable, have the transformer taps set down.
If you have fluctuating voltage consider putting small auto-transformer booster on your motors and then set your transformer taps down. If most of your motor loads come off one panel, you can boost the voltage of the whole panel with two small boost transformers connected as auto transformers.
yours

 

[wareagle]

You need to check the voltage at off peak load. If you are at 124 at peak it may be much higher at off peak.

 

[saladhawks]

You also need to note where you are taking the voltage measurements. Most utilities, including the one I work for, utilize ANSI C84.1 as the applicable voltage standard. This standard defines voltage ranges at 2 locations on electric power systems:

(1) Service Voltage - point-of-common coupling (PCC) between Customer and Utility. Voltage range of +/- 5%

(2) Utilization Voltage - voltage at line terminal's of utilization equipment (within Customer site). Voltage range of + 4.2%, - 8.3%.

 

[Senselessticker]

A simple solution would be to use lamps rated for 130V if this is the only problem associated with voltage levels/fluctuations.

 

[tommom]

Take a voltage at the transformer at off-peak. The voltage should not be higher than 126 volts. If it is, raise the tap to lower the voltage. If it is not, try 130 volt bulbs - keep in mind they will not be as bright.