Lightning and your well pump: a Central Florida problem

A submersible well pump is an electric motor hanging a hundred feet or so down a well, connected to your house by a long copper cable and sitting in water. In most of the country that arrangement never gives lightning a second thought. Central Florida is not most of the country.

Why this is a Florida problem

The National Weather Service office that covers east Central Florida describes the region as the lightning capital of the United States, and notes that Florida has the highest number of lightning casualties of any state, with lightning responsible for more weather-related deaths in Florida than all other weather hazards combined. Marion County is in the middle of that belt, and its summer afternoons are built around thunderstorms.

National Weather Service Melbourne, Lightning information

A well does not need to be struck to be damaged. A strike nearby, on a power line or in the ground, can send a surge along the wiring and down the drop cable to the motor. The pump is the far end of a long antenna.

What a surge actually damages

Franklin Electric, one of the largest submersible motor makers, sells surge arrestors specifically to protect submersible motors from commonly occurring high voltage spikes, which it says can damage the motor insulation system and cause motor winding failure. The same page is candid about the limit: no surge protection will save a motor from a direct strike.

Franklin Electric, Surge arrestor for submersible motors

In practice, storm damage shows up in a few places, and not always in the motor:

• The pressure switch. Contacts welded or burnt, so the pump will not start or will not stop.
• The control box, on three-wire pumps. The capacitor and relay are sensitive, and a failed box makes a healthy pump hum without starting.
• The breaker. Tripped by the surge, sometimes the only casualty.
• The motor windings or the drop cable. The expensive end, usually confirmed by insulation readings from the surface.

Weakened insulation does not always fail the same day. A pump that struggles or trips its breaker a few weeks after a close strike may be showing the damage late.

After a storm: what to check

1. The breaker. Reset it once. If it trips again, leave it off; that is a fault, not bad luck.
2. The pressure switch. If pressure is near zero, the low-pressure cutoff may have tripped during an outage. The reset lever is often the whole repair.
3. Smell and sound. A burnt smell at the switch or control box, or a pump that hums without starting, points at electrical damage near the surface.
4. Write it down. The date of the storm, what you noticed and when. If this becomes an insurance claim, that record matters.

The full troubleshooting order, with a table of symptoms, is in the pump not working article.

Protecting the pump

There are two layers, and they do different jobs.

• A surge or lightning arrestor for the pump circuit. Installed at the pump's disconnect or control box and grounded properly, it gives a surge a path to ground before it reaches the motor. Manufacturers are specific that grounding is what makes an arrestor work, so this is a job for a licensed well contractor or electrician rather than a weekend.
• A whole-house surge protective device at the main panel. It protects every circuit, including the well, from surges arriving on the utility lines.

Neither stops a direct strike, and both are cheap next to a pump pulled out of a 105 foot well. If you are having any electrical work done on the well, ask whether an arrestor is fitted and grounded. If it is not, that is the moment to add one.

Median Marion County well depth: Florida Well Data, Marion County well records

Will insurance pay?

Possibly, which is more than can be said for most well pump failures. Lightning is among the perils homeowners policies commonly cover, while mechanical or electrical breakdown and ordinary wear are commonly excluded. That makes the cause of the failure the whole question, and a contractor's written diagnosis naming storm damage the most useful document you can have.

Policygenius, Does home insurance cover well pump repair?

Keep the damaged parts until your insurer says you can dispose of them. What homeowners insurance does and does not cover on a well.

Questions people ask