I would say that you need to make the take off from the house via an ELCB ( earth leakage circuit breaker) or RCB ( residual current circuit breaker). The easiest way to do this is to buy a 'plug-in circuit-breaker like you would use for an electric mower etc and run the cable from this . ( basically a long extention lead)Use 'Arctic cable as this is weather proof. The only problem with this method is that you can only run upto 13amps.on that line. If you wish to run more it is worth running the line through an RCB consumer box. Multi channel,,,taken off your main consumer unit as a seperate spur.