Hello, What gauge/tyoe of wire should I run under my patio for a future garden lighting circuit? Should it be in a conduit if so which type please. Thank you
You shouldn't just chuck in a bit of cable under the patio, it needs to be properly buried at the correct depth or clipped to a wall.
You need to spec out what you actually want to achieve. Come up with a suitable design and tell us what you want to do and someone will most likely be able to help, but expect the answer to probably be "get a spark in".
you would need to use SWA for outside circuits to be done properly but if its a new circuit its notifiable and yes here it comes Get a sparky in.
I'm not normally part of the get an electrician (yes that is what they are really called) gang but you genuinely sound out of your depth on this one with incredibly limited knowledge. Spend a year constantly reading about the subject and watching as many videos as possible and then think about it again. Or get someone to do it for you. You can't decide to take on such a project on a whim to save a few quid.