How to protect well pump from lightning?

Get a service entrance TVSS and an appropriate secondary surge protector at the pump. Look at the Cutler Hammer or Square D site

There are "lightning arrestors" designed to help protect your equipment from the effects of distant lightning strikes. They, like most everythnig else, become less effective as the strike gets closer and closer to your site The problem is, as the effectiveness goes up, so does the price and at some point it becomes less expensive to replace the equipment! The other problem is that if they work, they only work once and then if not vaporized in the process, you have no way of knowing if they are still functional. The best method of protection is to open your breakers during a storm or put in a line isolation contactoor that is open all the time except exactly when the pump must run. A lightning hit must be almost direct to make it jump an air gap. Nothing can protect your equipment from a direct hit.

If you have a direct lightning strike, then you'r toast, but if the problem is electrical spikes coming in on the power lines, which is most probable, then a good surge protector should solve your problem. A good product is made by Meter Treater of Lake Park FL. Phone is 561-845-2007. They make a product that can take multiple surge hits before the internal elements are all destroyed. The unit has a light indication that it is still good. You might contact them and get some lititerature.

The unit that can be used for your pump can also be used to protect a normal home load center.

With this installed, you will sleep when the lightning is poping around you.

Is your pump submersible? If so the problem is more likely as the pump cabling becomes a good earth for the spike to travel down. Lightning strike is also a major concern in underground mines and special earthing arrangements must be made to prevent it. So, first step ensure your system earthing is good or the system neutral can bring you some really nasty stuff. Contact your pump manufacturer for advice and hopefully an engineered package. If not, electrical equipment manufacturers make effective surge suppression and self indicating arresters are likely to be useful so you know if they have failed. When I install surge suppression, I buy extra cartridges and leave them with the customer so that their equipment doesn't remain unprotected. Schnieder electric manufacture the required gear.

Almost forgot to say install a good breaker or HRC fuses on the line side of the surge suppression for indication as much as immediate protection. The fast rise time of the lightning pulse sees the insulation in your pump as the dielectric of a capacitor.

Something else nearby carrying a lightning conductor would be a good way. That way, lightning will take this path preferentially.

Ever seen the film/movie "Back to the Future"?