I tried using the water the other day, and - no water. I went into the kitchen and no water there. it was the weekend, so I immediately thought of $$$$$$ for a weekend service call and a new well pump. I checked the circuit breaker and it wasn't tripped - which gave me a little hope that it wasn't going to be a major repair bill. I went to the well pump pressure tank and surprise. The plastic shroud over the well pump pressure switch had a hole melted through the top. I could see assorted black stuff through the hole, like a major current surge had fried things.

I took off the plastic cover and the switch looked like it had run under ten times normal current. The wire end was vaporized, the tail of the crimp connector was gone, and the head of the crimp was melted and fused to the attaching screw, which had welded itself to the screw holder. I couldn't get the screw to budge.

I installed a new pressure switch/relay and things have been normal since. No problems.

Pictures attached. I suspect that the crimp wasn't crimped enough and the connector had overheated due to a higher than usual resistance. The pump causes a lot of vibration as it pumps the water through the piping to the pressure tank, so the crimp probably loosened up even more and eventually got high enough resistance that it blew.

For $20 and an hour of my time, we had water again!

Yup that is a bad connection but I haven't seen one blow a hole in the cover like that. It has been cooking a while.

Looks more like a melt through the cover based on the concave of the plastic. I have a receptacle from my grandmothers house that looks worse, but recently removed a receptacle from a neighbors house that was completely disintigrated from high resistance connections, it just crumbled in my hands. When looking at these and looking at the studs, you just are thankful to higher powers that the whole house did not go.

Shane

Yes,
I've lost count of the number of times I've seen a pressure switch on a water pump that looks like this.
And quite possibly a few air compressors as well.
InspectorE,
Does the pump run normally now?, as in it builds up to pressure and then shuts off for a certain amount of time (like hours or minutes and not seconds?)
Obviously I don't know how your particular system is configured, but things like faulty check valves and pressure tank diaphragms can cause a pump system to never actually (or only momentarily) attain the cut-out pressure and that will ruin the contacts in any pressure switch over time especially if there is a single phase Cap Start- Cap Run motor on the end of it, them things draw a hideous amount of current upon intial start-up.