well grounded in Kansas
Member
- Location
- Overland Park KS
Some time ago I started a thread that called Three Phase Site - Multiple Electrical Issues. To recap and be brief this site is a three building wood frame complex for elderly care and built to residential standards, but has a 1600 amp three phase main panel. There have been and continues to be multiple electrical issues on both high and low voltage systems. We are one of the low voltage guys and experience device resets and lockups, but fortunately have not had to replace gear. Here is what has been replaced:
1) PTAC thermostats by the dozens
2) CF lights. Sometimes 4 go out at the same time.
3) Hallway Emg. Lights come on for no apparent reason.
4) 3 Fire panels have been replaced.
5) AFIC breakers trip randomly or so it seems.
6) UPS units log alerts when no power failure seems to occur.
7) Ballast have been replaced multiple times.
8) A maintenance worker reported being shocked when he touched the neutral or ground wire.
What we know. A power study was done and current harmonics was sometimes 15 to 20%. The installation company did not run a neutral for each branch circuit and all of the bedrooms with AFIC have shared neutrals. The first grounding system was inadequate and was three rods bonded was added to the 1600 amp service, but two separate buildings with their own panels were not grounded until recently. That EC left them un-interconnected. All three buildings are separately grounded now, but feed from the same 1600 amp main and transformer.
Over the last several months I have connected a power quality meter (Fluke 43b) and logged transient spikes of at least 50% RMS of 120VAC. In a three day period on several occasions it exceeded the 40 captures the meter stores and at other times it will range from 10 to 38 in a three day period.
My question for the forum is how many transients spikes of that degree (60VAC) is normal. I know if a perfect world zero is the answer, but this facility is not normal. Any other input is appreciated too.
1) PTAC thermostats by the dozens
2) CF lights. Sometimes 4 go out at the same time.
3) Hallway Emg. Lights come on for no apparent reason.
4) 3 Fire panels have been replaced.
5) AFIC breakers trip randomly or so it seems.
6) UPS units log alerts when no power failure seems to occur.
7) Ballast have been replaced multiple times.
8) A maintenance worker reported being shocked when he touched the neutral or ground wire.
What we know. A power study was done and current harmonics was sometimes 15 to 20%. The installation company did not run a neutral for each branch circuit and all of the bedrooms with AFIC have shared neutrals. The first grounding system was inadequate and was three rods bonded was added to the 1600 amp service, but two separate buildings with their own panels were not grounded until recently. That EC left them un-interconnected. All three buildings are separately grounded now, but feed from the same 1600 amp main and transformer.
Over the last several months I have connected a power quality meter (Fluke 43b) and logged transient spikes of at least 50% RMS of 120VAC. In a three day period on several occasions it exceeded the 40 captures the meter stores and at other times it will range from 10 to 38 in a three day period.
My question for the forum is how many transients spikes of that degree (60VAC) is normal. I know if a perfect world zero is the answer, but this facility is not normal. Any other input is appreciated too.