Victorian Clock
What exactly makes digital clocks speed up when the power supply is weak?
I once moved into an old Victorian that I would have sworn was haunted because all my clocks immediately started gaining time daily. Then, an electrical engineering professor explained to me that there wasn't enough current running thru the house. Based upon his recommendation, I contacted the electric company who came out, updated my box and stopped the problem. But, I can't remember the details of why he said the slow current made my clocks run faster. Refresh me, please.
There was probably an instability in the wiring due to he previous box. This instability could cause the oscillator inside the clock to malfunction thus changing the speed of the clock, in your case making the clocks run faster.