What breakers and rcbs do I need for my consumer unit ?

I am wiring up lighting and sockets, plus 2 water pumps for a swimming pool into a shed in our garden and need to know what breakers and rcd's I would need to fit into a consumer unit. The main cable is a 4mm swa cable, that has been calculated to a max rating over the distance of 2200watts. We will be running 1x single phase pump @ 750watts then another small single phase pump @ 150 watts, then 2x 150watt halogen floodlights, 2 x double sockets for small appliances and 2 x 55watt bulbs inside. I want to fit a rcb to add extra protection if anything went wrong with the pumps, but am not sure what rating I need and also what rating I need for the mcb's ,ideally one for sockets, another for the 2 halogens, 2 pumps, and interior lights ?.

What breakers and rcbs do I need for my consumer unit ?
This is what I would do. You don't want to use the minimum number of breakers. If one trips you lose too many tings. Install a breaker box in the shed off your main breaker box. You need a 50 amp main breaker in this box. Install a 20 amp breaker for the main pool pump. Remember, the pumps will have a high inrush current as they start. This can be almost twice the running current. Install a 20 amp breaker for the small pump and the halogen lights. Install a 15 or 20 amp breaker for the outlets. Install a 15 or 20 amp breaker for the interior lights.


Around a pool or any outdoor area make sure everything has GFI protection on it. Get a permit and have everything inspected. You insurance company will probably deny any claims from work that has not been inspected and passed by the local building dept. If it's not inspected and somebody gets hurt, any damages might have to come out of your pocket.