The building is 3 years old; 5 years before, it was a patch of dirt. There has been extensive utility work done in that area. The building is served by it's own pad-mounted transformer, 208 3 phase.
The building itself has 6 tenant meters, and a 'house' meter. My problem is with circuits served by the house meter; other areas seem to not have the problem I am addressing.
While the other services have 3 phase HVAC loads, the house meter only serves nine single-phase 120 circuits. Five of these are lighting circuits, and one is the lighting controls.
My problem? I an losing electronic HID ballasts. 17 of 39 so far. The ballast maker tells me they look as if they received some sort of voltage spike. Lighting circuits are loaded to about 8 amps each.
I have also lost a photocell - 25 amp rated, controlling about 8 amps of HID pole lights.
Finally, I had a new Intermatic electronic timer, with battery back-up, fail several times to keep time. That is, it would suddenly drop an hour or two. This timer works with a photocell to control the two lighting contactors. These controls have their own neutral to the panel.
All panel connections are tight.
None of the tenant spaces are losing fluorescent ballasts, or experiencing light flicker.
I'm interested to see what the data logger picks up. Please keep us posted Reno...
Seeing as how you're burning out control devices, I would suggest putting a contactor in the control circuit. Electronic timers can be pretty pricey (intermatics, anyway) and the 25A photcells are about $22 too, so you can save yourself some service calls and waranty work by taking the HID load off of those items. I go through a lot of 25A cells whenever they are running without a contactor, especially on ballasted fixtures.
I want to say harmonics sound like a possible culprit, based on the HID factor, but the logger should bring the problem to the surface.
Zapped ,,, I have a pair of contactors. The 'control circuit" has the photocell, the timer, and the pontactor coils on it. Period. It also has its' own dedicated neutral.
I'm also losing ballasts ... nearly half of them ... $230 each, electronic HID ballasts only 3 years old. Now, these are spread over several circuits, and I agree that a loose neutral connection might cause voltage surges. Yet, even in those instances, the loads are really well balanced - again, mitigating the effect of a loose neutral. Overall, the sparky who did the place did a very good job.
Now, the pole lights are on their own photocell, and no contactor ... but a 25 amp rated photocell ought to be plenty for 800 watts of MH!
So, all I can do is wait and see what the datalogger shows - though I might take apart some of the switchgear, just to see if I can spot anything not 'right.'
Reno, Another source of spikes is an occasional lightning storm in the area. You mentioned parking lot lights. I have seen damage in parking lot fixtures and also several hundred feet inside buildings when poles attract the big sparks. That is why some engineers require a ground rod in the concrete base of metal parking lot poles.
Another possibility could be faulty underground 12.5kv utility wiring coupling to parking lot wiring.
Have you checked the impedance of the ground and neutral for the house panel? Ideal makes a fairly inexpensive tester ($200) that can be used to test branch circuit and feeder ground impedance.
On the subject of switching those outside ballasts, in my experience a contactor or heavy duty lighting relay seems to work more reliably than a photocell only. If the photocell is not conducting the full sine wave, there could be harmonics created by the photocell. If the photocell has a relay, the contacts are usually pretty small. Some photocells use solid state relays which could be source of your problem if they are acting like a dimmer-only conducting for a percentage of the sine wave.
And a final suggestion, what is the voltage drop on the circuits at the actual load?
I'm sure you have thought of this but just in case: If there are no complaints of a similar nature from the tenants (None of the tenant spaces are losing fluorescent ballasts, or experiencing light flicker.), then I would suspect a poor connection somewhere between the final point of connection of the transformer and the house panel. If it were a utility problem one would think it would affect the tenants as well??
You should also keep in mind that many, if not most, spikes can be generated within the facility. Motor loads, especially refrigeration/cooling seem to be big offenders. If the problem does end up being spikes, you'll likely end up putting some protection on the house panel, but I wouldn't spend a nickel until you see the results from the POCO.
Do the tenant spaces have the same type of lighting & ballasts? You mentioned the ballasts were for HID fixtures, which I will assume means something other than fluorescent. If that is the case, I don't feel that the technology for electronic HID ballasts is anywhere near being mature. Early on in the T5HO technology rollout, I ended up replacing 90% of the ballasts in one installation.
Also, if all the ballasts were from one lot, there is the possibility of a manufacturing defect that the manufacturer may not have detected as yet.
I'm definitely interested in seeing the outcome, keep us posted.
Few things are harder to put up with than the annoyance of a good example.
Re: Voltage spike source?
#183927 01/27/0904:16 AM01/27/0904:16 AM
Since Electronic / SMPS Ballasts for HID Lighting are relatively new to the Industry, I would expect some early failure issues.
The Ballasts _SHOULD_ have some sort of Factory Installed TVSS Protection on the Line Input side of the Ballast. The level of TVSS may not be as beefy as needed, or might be built too sensitive to TVS/S.
Just before the Line "PI" Filter - if installed, there should be - at the least - two MOVs.
Just out of curiousity, where any discrete components visually "fried"? If so, what components lost smoke, or where are their locations on the Ballast's PCB?
The source of the Spikes / Surges would be from something generating trash back into the system, at "Off Hours" - i.e., when it is dark, and the Site Lighting is active. Could be late night, could be early AM (pre-dawn).
Things to consider:
1: Are there any other Customers fed from the same Transformer's Secondary, besides the ones fed from this Service Section?
Other Customers may be creating issues with their equipment, and doing so during off hours.
2: Are there any Customers fed from this Service Section, which might be working late night (dusk to maybe 12:00 AM), or early morning (2:00 AM to dawn)? They might be running noisy equipment, causing the TVS/S issues.
3: Might be some Tenants on this Service Section with noisy HVAC equipment, which automatically starts in pre-dawn hours.
4: Utility may have a Power factor Correcting Capacitor bank, which "Cuts-Out" at an off peak time (like 8:00 PM), or "Cuts-In" prior to peak time (like 4:00 AM), and when the Cap's are Cut-In or Cut-Out, creates TVS/S issues, or an overvoltage scenario.
5: May be heavy use, 24 Hour shift Customers on the same Primary Circuit, which are creating noise issues during night time hours.
Verify the time frame & duration of the noise (Spikes / Surges) with the Datalogger, to determine if there is an issue with TVS/S (Transient Voltage Spikes/Surges).
If there is an issue with TVS/S, may need to fit the House Panelboard with an SPD Panel, or query the Ballast Manufacturer for Point-Of-Use TVSS devices.
BTW, who made the Ballasts, and what are the ratings?
If the costs and maintenance factor prohibit an extensive TVSS application, the Fixtures may need to be "Retro Engineered" back to Reactor based Ballasts (Magnetic Ballasts). Could use the "F-Can" enclosure types, or the "Pole-Based" round ones.
Will see what arises from your next reply(s).
Scott " 35 " Thompson Just Say NO To Green Eggs And Ham!