poolguynj....true....the lightning surge can not be stopped but other things start to happen if the surge reaches a high enough voltage....things like arcing in the panel and even arcing at the electrical outlets in and outside the home. This arcing dissipates the surge energy quickly. If the drive is designed at a high enough withstand voltage, it won't be harmed because the surge voltage will never go higher than the withstand voltage because of the upstream arcing. This arcing is very predictable and happens consistently at a discrete voltage. There are drives out there today that have been designed at this withstand voltage so they won't be harmed by lightning surges in residential applications. Hope this helps!

Just regarding surge suppressors for sensitive equipment-- I would like to recommend individual surge suppressors by Zerosurge. (I know Davidr has seen my spiel on Zerosurge before, but I assure you I have no interest in or relationship with the company; I just think their products are great). Zerosurge's suppressors are different, because they do NOT use MOV's. Most suppressors use MOV's to divert surge current, and that's how they've been built for years, with often not such great results. An MOV suppressor loses effectiveness with each surge it suppresses, or even with just one surge, until it becomes ineffective, often without the homeowner's knowledge. I think that MOV method is one of those things that have always been used, and everyone is stuck in a rut about them, but there is better technology out there, e.g. from Zerosurge. Here's a link to Zerosurge's page which explains the no-MOV's technology. Also on that website, check out the tab on the left called "surge suppression info", which has a lot of informative material. Here is a link that might be useful: Zerosurge Surge Suppressors

When the HVAC did not have any PC boards the surge protection was not needed, but when manufacturers started using electronics, this requires protection against lightning. Most manufacturers use some form of electronics on modern HVAC equipment.

Good question. I did a survey in 2004, and determined that the specifications of various surge protection was different from what the components were rated for, so this answer is unknown. I have extensive electronics background, and I stumbled when trying to compare specifications. When you buy from switchgear manufacturers, the cost is higher than what HVAC equipment costs, but when compared to the MOV surge electronics the price is much higher. Based on what I found, the protection should be included in new switch gear at no additional cost, but this will never happen.