[vintage_tube]

About 10 years ago I had a similar problem following a direct lighting strike to a tree at my neighbors house across the street. Both my wife and I were watching the storm from our garage (doors up). The strike, the first I had actually seen from a 50-75 foot distance, was intense.

The tree caught fire, but the heavy rain doused it over a period of time.

The lightening strike took out 1 HVAC, all TV's & satellite receivers, a M/W, a refrigerator, a freezer, a desktop PC, and to show how intense it was, it blew a 2d floor corner spot light and metal housing located on the soffit 50 feet into another neighbors yard. I believe it also melted 1 15amp breaker.

That same evening, as the storm passed, I noticed a flickering of our lamps. Intermittent, yet repetious but not one where you could record or notice a duration nor pattern.

A few days passed, and opened a trouble ticket with Duke Power. They came out, put a recording monitor on my meter. While that was collecting data, I took out my Fluke VOM and attached the leads to an empty outlet near the chair I sat in during the evenings. Armed with paper and a pencil, I recorded voltage readings. Sure enough, 121V, 109V, 112V, etc. Nothing IIRC below 106V but definitely not a steady 120V.

Two days later the Duke Crew returned and retrieved & analyzed the incoming voltage data. I presented them with what I recorded, etc.

It took them nearly a month to resolve and understand it was related to a bad tap on a transformer in the corner of a yard adjacent to where the strike occurred. Why it only affected my house is anyone's guess.

After that & being in communications where all our facilities are equipped with Transient Voltage Surge Protectors (TVSS); I started looking into them & other Surge Protection Devices (SPD's). Not inexpensive when one adds up install costs -- an APC or ABB or equivalent Square D unit attached after the meter (can't attach to prior to the meter) would be a cool $3.5K plus.

Around that time, Duke Power began offering their version of a whole house protective device which attached to the meter base & then the meter clamps to that. Monthly costs at the time $4.95 (now around $7). Not as robust as a standalone unit by those other companies, but it does offer a peace of mind to a degree. A direct strike like my neighbor experienced with millions of volts going every which way towards least resistance -- nothing can protect from that 100%. Like many here on AA, during storms and weekend getaways, I unplug all audio gear/TVs & to preclude a water fiasco while away, I also turn it off to the house as well.

Like others who have commented to the OP, I'd be on FP&L like SoS and hound them until the issue was resolved; especially if you were the only one in your area experiencing the fluctuations (the OP didn't say if others left & right of him nor across the street were also experiencing the issue -- I'm assuming they aren't).

Additionally, FP&L must be extremely proud of their power surge protection devices they offer at $15 per month. IMHO, regardless of FP&L pricing, it should be seriously considered. The link to it is here (fill in the missing "tt" characters):

h..p://www.fples.com/surge-protection-homeowners.html

I have also attached a word doc you may be interested in.

Best of luck to you,

Bob