My LED pool lights are hardwired into a GFCI outlet on a pole near the spa, but the single pole switch for those lights is inside my house. I've never had a problem with the GFCI tripping prematurely, and testing using the button on the outlet seems to work as intended.

Due to far too many times in which we've accidentally left the pool lights on until the next evening, I decided to buy a digital timer (Leviton LTB12-1LZ 12 hour digital count down timer rated for LEDs up to 600 watts) to replace the single pole switch. This design requires a neutral connection in the wall box which I have. I wired the line wire, load wire, neutral wire, and ground wire as instructed (and yes, I did it correctly). Unfortunately, turning the power back on to circuit resulted in the GFCI tripping immediately and being unable to reset. Swapping the new digital timer out for the old single pole switch cured the problem, so it's something to do with the digital timer or the way in which the timer is wired.

Research on this problem suggests (though is not definitive or particularly clear) that the best way to wire GFCIs, switches (or digital timers), and any sort of load is to have the GFCI upstream of the on-off switch because any sort of trigger or variation for the juice entering the GFCI (such as due to a digital timer) could trip it. That might be the optimal approach, but it's not possible\practical with my system.

What I'm wondering is whether the issue might be avoided if I opted for a digital switch designed for older homes that predate the "neutral in every wall box" code regs. Such digital switches (such as the Eaton PT18M-W-K) only require three wires: line, load, and ground. The electronics in this switch are presumably powered by the current running through the ground (I assume). I'm thinking that not having the digital timer connected directly to the neutral in the wire box might avoid fluctuation in the current that seems to be triggering the GFCI to sense a fault and trip itself.

The other option, a spring wound timer, is certainly cheap and would do the trick, but I don't want to hear tick-tick-tick as it winds down and few such timers are designed to be turned off manually (in theory, turning the knob counterclockwise on a spring loaded device is not good practice).

Any ideas of how to get a digital timer in there without rewiring everything?

Thanks!

Nick in Palm Springs