Electrical Fault? Eversource Denies Blame For Reported Power Surge

CHATHAM – When it comes to allegations by around 20 people that their solar inverters and other electronics were fried by a power surge last summer, Eversource engineers have a simple answer. They don’t know what caused the problem, but it wasn’t the fault of the utility.

 Last Aug. 19 to 20, some properties in town apparently received a powerful electrical surge that destroyed hundreds of appliances including components of home solar systems. That’s the claim being made by resident Jeffrey Vanacore and a group of around 20 others who brought their concerns to the energy and climate action committee, and then to the select board on Feb. 17. Vanacore asked the town to petition Eversource to send experts to answer questions.

 Last week, the utility did so, sending Community Relations Manager Ronit Goldstein and two distribution engineers, Tyler Thibault and Rafael Gutierrez, to speak to the energy committee.

 Vanacore said the apparent power surge destroyed hundreds of microinverters attached to individual rooftop solar panels, all manufactured by California-based Enphase Energy. But also damaged were heating and cooling system components, an electric stove, a computer and an electric vehicle charger. Gutierrez said Eversource brought in a team of its experts and an outside consultant to investigate, looking at all of the current-measuring devices on the so-called 95B Circuit, which serves Brewster, Chatham and Harwich.

 “The short story is, nothing was found. No deterioration, no ionization, no gassing, no arcing. There was no evidence of an overvoltage or arcing incident in Mr. Vanacore’s panel, and there was no event on the distribution grid,” Gutierrez said. Had there been a surge on the grid, it would have been detected and documented, and would have damaged sensitive fire and gas detection equipment elsewhere on the circuit, along with communications and wastewater treatment equipment, he added.

 “We wouldn’t be here if we had a grid-level event, because we’d be paying out hundreds to thousands of claims,” Gutierrez said. While 20 properties reported damage during those two days, most of the 5,125 customers on the circuit had no damage. There are 347 solar customers on the 95B Circuit, and “327 are OK in that same time frame,” he added.

 “Twenty totally independent events, is what you’re telling me happened?” energy committee Chair Robert Wirtshafter asked.

 “No, actually, I’m not saying that any events happened,” Gutierrez replied. Wirtshafter asked if lightning might have been the culprit. “We can discount a lightning strike Aug. 19 to 20, however three weeks in July, up to the 25th of July, we had severe activity over Chatham,” Gutierrez said. Even when there’s no direct strike, lightning can cause damage to sensitive equipment that causes it to fail some time later, he said.

 Wirtshafter said it seems statistically unlikely that 20 customers would report a problem at the same time without some connection related to the grid. “You have to start addressing where this happened,” he said.

 Gutierrez pointed to a letter addressed to the committee by an attorney representing Enphase Energy, which made the damaged solar microinverters. “At a high level, the available data indicates excessive input voltage to certain affected microinverters during the event,” the letter reads. “However, Enphase wishes to stress that this data merely shows that Enphase microinverters were affected by an overvoltage event; the data does not indicate the actual source of such event.”

 Gutierrez said the letter makes it clear that any surge was on the homeowner’s side of the electrical meter, where Eversource has no responsibility for problems. “The input voltage to microinverters come from the solar panels and the DC modules on the solar panels. We’re not the input to the microinverters,” Gutierrez said.

 “It doesn’t explain to me how other equipment was blown out too, though,” Wirtshafter said.

 Thibault said he can’t speculate on what happened with the customers’ own equipment. “We don’t do anything beyond the meter,” he said. “We actually went above and beyond with Mr. Vanacore by bringing in the third party consultant,” he said. The conclusion was clear, Thibault said. “It wasn’t anything on our side.”

Wirtschafter said he still finds it hard to believe that 20 independent systems had failures at the same time.

 “I suspect the number will probably grow after this meeting,” Gutierrez said. “Now I’m not trying to be a wiseass, but first there were three [claims]. Then there were seven. Now there are 20.” He also refuted the timing of the reports. “Respectfully, I don’t think it happened at the same time. I really don’t. I think there’s some bandwagoning going on; I think there’s some coaching going on,” he said. 

Vanacore, speaking at the meeting, said homeowners have many other questions for Eversource to address. “The vast majority of homeowners had surge protectors,” he noted. Vanacore said he has three surge protectors in his house. “The question is, if the surge protectors didn’t get it, what happened?”

 “If you have surge protectors and they weren’t damaged, then it didn’t come from that direction,” Wirtshafter said. “Honestly, this is befuddling. Everything makes sense that it was one event, but there’s nothing tying it together as one event – except for logic. But that just leaves us all with a problem: that we have this susceptibility of this happening again, and no idea why it happened or how to protect ourselves.”

 “Solar seems to cause a lot of customer problems,” Thibault said. The issue is generally installation, Gutierrez added.

 “Some installers have been out there for 20-plus years doing business, and they nail it every time,” he said. “We see the ones where they don’t get it right.” While he said he’s not speculating that solar installations were to blame in these cases, “if an installer reaches into their pocket and pulls out a standard screw instead of the correct compatible hardware for the bonding lugs and the bonding braids, they’re wrong. It really is that intricate,” Gutierrez said. 

Resident Thomas Campbell suggested that the committee invite representatives from Enphase and the local solar installer to provide more information. “Perhaps these two other organizations can provide some additional information.”

Wirtshafter said the issue will be continued in a future agenda.

 “I’m still befuddled,” he said.