Symptom: Lights dim when appliances or laserjet printer kick in while HVAC and clothes dryer running.
I currently have a 400 Amp service split into 2 panels each with a 200A main breaker. I'm all electric, no gas. House built in '96, one floor. Main feed comes in garage.
On one panel, I have 350A combined breakers (15A is not used, attic fan removed) and the other side 245A combined breakers (60A not used, was added for a jacuzzi that previous owners never put in).
I already had an electrician come to the house to loosen and tighten all the connections on the panel.
My thought is, I don't have proper distribution of power across the panels. However, I'm not an electrician, so I don't know for sure. But by looking at both panels, it seems the one side may be demanding a lot and not very well balanced.
I then noticed the office which has the laserjet printer is tied to the lighting in the living room and hallway. So I can see how the printer could be dimming those lights. However, the kitchen appliances are on a separate breaker which also cause the lights to dim.
I plan on running a dedicated line for the printer and office computer on the panel that consumes less power hoping this would fix it. However, I want to hear some other thoughts and possible solutions to this.
Best Answer
You did the right thing first tightening the connections, next would be to use an AMP clamp meter to verify the loads connected to L1, L2 and make sure they are ballanced, if unballanced as stated above some breakers need to be moved untill they are ballanced. if they are ballanced it may be your main breaker has a weak hammer on 1 leg causing some internal arcing and the voltage drop. I had to replace a square D panel several years ago as I could not get a new main breaker from square D