My pool uses a 110V, 20 amp pump motor, specifically a Hayward Super Pump. Not sure on the HP rating but I believe it's the 1HP model based on the amperage. The pump uses a NEMA 5-20 plug, into a 20 amp GFCI socket, into 20 amp dedicated circuit.
In between the plug and the socket, I've added an Intermatic HB114 Heavy Duty timer, rated for up to 2HP motors. Ideally, I'd like the pump to turn on and off three times a day at various times, which I tweak depending on season, usage, and weather. The problem with that is, each time it turns off, there is a large arc. It seems unreasonably large to me. The arc is clearly visible through the opaque plastic housing of the timer, not just through gaps, but it actually illuminates the plastic. I believe the arc is destroying my timers, as their reliability significantly decreases after a month or so of operation, to the point that the mechanism doesn't turn properly and they no longer reliably turn the pump on or off and have to be replaced.
After giving up on the timer idea, I tried plugging and unplugging the motor manually, usually on a daily basis. Unfortunately, the arcing continued, and a month or so of doing that appears to have damaged both the socket and the plug. The tips of one of the prongs is visibly shortened from what it was before, and looks like it has been attacked by an angle grinder. Speaking with the previous owners, they confirmed the problem and explained that they simply left the pump plugged in 24/7. Due to rising electricity prices, this is not a reasonable option for me.
Aside from repairing all this damage that I did last year, I want to avoid a repeat of the situation this year. Is there anything I can do to avoid this situation in the future? Would a more expensive digital rather than mechanical timer help? Would hard-wiring the pump help? Is there some kind of arc-suppressor device or some kind of switch or power supply or capacitor that would help? Do I need a new/different pump? Should I consult an electrician?