I stumbled upon these “MC4” connector for roof solar panels. Supposedly rated for 30A and IP68. I guess they are fine at more then double current. Same diameter as 4mm bullet/banana so inserts might just be directly swappable (at least male is just to click in).
Dirt cheap at 3 EUR per pair in my country.
I will play around with these as phase conectors, lets see how they like 60A 
