This turned into a much longer saga than anticipated.
My next attempt to remedy the "electrocution waiting to happen" (see post 11) was to enclose waterproof wire nuts (they aren't) inside a waterproof junction box (it isn't). I completely filled the j box with silicone goo, leaving no possible point of entry for water. A permanent, waterproof fix! Until it wasn't.
This setup worked fine for 2 years. Then we had an unbelievable series of massive storms this past winter. Poof went the GFCI. Some tiny amount of water had sneaked past the silicone goo. I had to tear out all the silicone, discard the j box, and start over.
I found the
WAGO connectors. These appear to be more secure than wire nuts; they actually clamp down on the wires such that the wires can't pull loose accidentally. The smallest ones were just the right size for my wires. But still not waterproof.
Then I found the
Wago Gelboxes. These are specifically made to waterproof the WAGO connectors and are rated at IPX8. Yeah! Ship me half a dozen! But these are not yet available in the USA. WAGO phone rep said "in the fall" and to call back in October or November. Fortunately, the gelboxes are available in England, so I had them imported. Shipping cost more than the devices themselves.
So I think I've finally solved the problem of water in my in-ground junction. Time will tell, of course, but at least I now have connections purpose-made to exclude water. First photo shows the wires with just the connectors; second photo shows the connectors encapsulated in the gelboxes. Wish me luck.

