Im researchng this as well to right now, glad i came across this post. Some 20amp dual pole breakers will allow two circuits per lug, like the Square D homeline or QO breakers. So if you already have one 20 amp dual pole breaker for say your pump, you should be able to just hook it up to that and share the breaker. Im not familiar with how these surge protectors work, so im not sure if it defeats the purpose of having one for your pump, if it shares the same breaker. Im running into the issue of not having enough space.