Salad Fingers, why do you continue to act like a moron and constantly have a sig that is pointed at a certain member of the DIYNot community?
It makes you out to have the maturity of a pre school bed wetter![]()
OP if you know nothing about electrics then you will need to employ a spark to investigate.
Classic fails with external electrical service tends to be stupid placement of junctions, lack of saleable on junctions and fittings.
Turn off the circuit, make sure it's completely off and on the next bright day go round everything that was done externally, remove covers and check for water ingress and / or insects such as spiders having made a home in a fitting.
Every external fitting should be ip rated, check for cable entries, drip loops on cables and any gaps or holes that might have allowed ingress. Sealant should be used if you find any moisture access after removing the offending item and either drying it out (swmbo hair drier) or replacing the item.
Have you ignored me

