At some point the lights in the house will have a noticeable flicker when an animated Christmas light show runs. But the question is, how much flicker (voltage change) is normal for the amount of current change you are producing and the electrical service you have. A general rule of thumb that I came upon when researching my problem was:
* A load change of 10% of the panel rating will cause visible light flicker.
My first year animating I was drawing 12 amps (on a 200 amp service) and had bad flicker in the house. After taking a lot of measurements I found a bad connection on my neutral in my meter base (can you say fire hazard). Replacing the meter base eliminated the flicker. The next year I was drawing 48 amps and still didn’t have any flicker.
Here’s a good article on Voltage Fluctuation and Light Flicker from BC Hydro:
BC Hydro - Power Quality - A guide to voltage fluctuation and light flicker
Last revised: December 06, 2013