While a properly grounded/bonded system is important, it is HIGHLY unlikely a ground could be causing this issue. As for a loose neutral, if you had a loose neutral and the load is balanced perfectly across the 3 phases there would be little or no problem, if the load has excessive imbalance you would be losing equipment FRYING the equipment due to over voltage.
What I would do.
If the flicker is happening all the time.
1. Use a multimeter and amp clamp (3 phase high speed recorder would be best) on min max and watch each phase voltage and current at the main service. Determine if the voltage drop is evident with a current increase of the site. As noted below a dip of 3. VAC can result in noticeable flicker.
2. Verify all connections from main service to load distribution panels. Once again expensive equipment would help facilitate this (IR Camera).
3. If you have voltage dips and no current increase then the issue is upstream of the service on the utility distribution. (assuming this is not a connection issue in your establishment).
4. Have you contacted the utility?
THIS is from a post I had on another forum.
This house had an unusual number of incandescent light fixtures 150+, and 7 HVAC units. This house had a 200 amp service that was upgraded to 600 amp, appears the utility left the 200 amp triplex in use, about 150" changed to 250 AL underground 150, plus what appears to be a 30 KVA pole mounted transformer (300 feet away).
Flicker is not just load, conductor length or transformer sizing dependent, it is also end user sensitive. I have flicker but never really notice it, unless the wife says something. I have been to customers houses where it PLAIN WAS DRIVING the homeowner crazy and max VD recorded was 3 VAC. Others are just worried they have connection issues (a legitimate concern).
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What I would do.
If the flicker is happening all the time.
1. Use a multimeter and amp clamp (3 phase high speed recorder would be best) on min max and watch each phase voltage and current at the main service. Determine if the voltage drop is evident with a current increase of the site. As noted below a dip of 3. VAC can result in noticeable flicker.
2. Verify all connections from main service to load distribution panels. Once again expensive equipment would help facilitate this (IR Camera).
3. If you have voltage dips and no current increase then the issue is upstream of the service on the utility distribution. (assuming this is not a connection issue in your establishment).
4. Have you contacted the utility?
THIS is from a post I had on another forum.
This house had an unusual number of incandescent light fixtures 150+, and 7 HVAC units. This house had a 200 amp service that was upgraded to 600 amp, appears the utility left the 200 amp triplex in use, about 150" changed to 250 AL underground 150, plus what appears to be a 30 KVA pole mounted transformer (300 feet away).
Flicker is not just load, conductor length or transformer sizing dependent, it is also end user sensitive. I have flicker but never really notice it, unless the wife says something. I have been to customers houses where it PLAIN WAS DRIVING the homeowner crazy and max VD recorded was 3 VAC. Others are just worried they have connection issues (a legitimate concern).



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