Sump Pump Control

I have a pretty simple question I believe on setting up a sump pump control box. I have a sump pump that is 120/1 with a thermal overload protection built in to the pump. The full load amps is rated at 5.8. I have a float switch for high and low. My question is on the overall box I was going to have a breaker disconnect at 8 amps. Is this okay to have since there is a thermal protection? I was then going to put in simple motor contactor like Siemens 3RT20151AK61 and break on the line side for a motor contactor? Should I just use a relay for something this small or stick with the contactor? I would then run the neutral to a terminal strip for the opposite side circuit and use a relay to turn the motor Line side on/off based on the level switches. It seems simple but I wanted to make sure I was not missing something that should be in place for a simple application. Should I fuse the motor after the CB? Should I fuse the control circuit? If I was to fuse the control circuit how big - 2A? I was going to have run indicator light so I could see it when it is running.

The 8 Amp breaker and the built-in thermal overload should take care of the protection requirements. I don't think you need a control fuse either. I would use a motor-rated contactor or relay (some relays are rated to handle motor starting current). If you want it to last many years even with frequent starting, go to the next higher-rated contactor.

The motor contactor 3RT20151AK61 is OK, and I also agree with Lancie.
You have to be careful in choosing the 8 amps breaker. If you pick a breaker with the wrong current curve, it might switch off when you start the pump (10xFLA).
Since you already have thermal protection, you can have a higher current breaker to protect the cable and turn OFF thepower.
I also suggest you use a 3 pos. switch (Aut 0 Man) so you can turn ON the pump, if the level switch doesn't work, for testing purpose etc.