Lights flickering

[Jimmy7]

Hello,
I have a customer who has geothermal equipment in his single family house. The house has a 400 amp service with two 200 amp panels side by side. The customer is concerned that when the geothermal equipment turns on the lights flicker, I’m guessing it’s the in-rush current. It appears that most of the geothermal equipment is in one of the 200 amp panels. As a result, the customer would like to remove and relocate any lighting circuit that is located in the panel where the geothermal is fed from to the other panel. This is an effort to stop the lights from flickering upon the start up of the geothermal system. Would this even work, or does the in-rush affect the entire 400 amp service? FYI - Prior to the geothermal install the entire house was fed from a 200 amp service.

 

[winnie]

Inrush will impact the entire service, perhaps _slightly_ less on the other 200A panel (because of separate conductors from wherever the service splits), but likely not significantly less.

Before doing any major work swapping components to _fix_ the problem, the first step is to reliably determine what the problem is.

1) Do the lights flicker when the geothermal equipment starts up, or when it is running?

2) Does the geothermal equipment have any VFDs or electronically commutated motors?

3) At the flickering lights on dimmers or otherwise controlled?

4) Do all lights in the house flicker, or only lights on certain circuits?

5) Have you placed any monitoring equipment on the service to measure things like voltage drop when the geothermal equipment is running?

Large electrical loads create voltage drop, which is known to cause flicker in even the simplest of lamps.

Electronic modulating loads (such as motors on VFDs) are known to create electrical nose, which is known to cause flicker in things such as dimmable LEDs.

Sometimes the solution is filtering on the source of the noise. Sometimes the solution is filtering on the sensitive loads.

-Jonathan

 

[Jimmy7]

Inrush will impact the entire service, perhaps _slightly_ less on the other 200A panel (because of separate conductors from wherever the service splits), but likely not significantly less.

Before doing any major work swapping components to _fix_ the problem, the first step is to reliably determine what the problem is.

1) Do the lights flicker when the geothermal equipment starts up, or when it is running?

2) Does the geothermal equipment have any VFDs or electronically commutated motors?

3) At the flickering lights on dimmers or otherwise controlled?

4) Do all lights in the house flicker, or only lights on certain circuits?

5) Have you placed any monitoring equipment on the service to measure things like voltage drop when the geothermal equipment is running?

Large electrical loads create voltage drop, which is known to cause flicker in even the simplest of lamps.

Electronic modulating loads (such as motors on VFDs) are known to create electrical nose, which is known to cause flicker in things such as dimmable LEDs.

Sometimes the solution is filtering on the source of the noise. Sometimes the solution is filtering on the sensitive loads.

-Jonathan

Good information, thank you. Let me do some homework on this.