Just wanted to get people's opinions regarding points of isolation for split a/c units and whether you have to supply a point of isolation both inside and out. I usually supply one at the outdoor unit with rotary isolator to be locked off if required and depending on outdoor unit location (ease of access) I'll supply one inside too. If the outdoor unit can be accessed easily I'll just supply one outside. I have worked on stacks of units that only have one point of isolation (outside) but have had some engineers say it needs both and some say not. I've also worked for several big companies where outside only is how they do it. It seems when you speak to electricians they are the same, some say it's fine as it can be locked off and some say it needs to be at either end.

What do other engineers do and is there actually a right or wrong way to do it? This is UK regs so will probably differ elsewhere I pressume, is it simply so it can be isolated safely whilst working on or protection? As most systems are fuse protected at the condensing unit anyway before it comes through to the indoor unit.

Just interested in getting others opinions on the matter as it seems to vary alot and abit of a grey area.