We had to tamper plastic lids, if I have to run externally in plastic tube I never fit boxes, glue all joints and drill 20mm holes thru walls so the tube goes straight in.Also do any bends with the spring bender.

have to say though havent came up against a wall yet where i couldnt get rear entry to bell etc (good collection of very long drills)

suppose problem arises if your doing external beams in a yard or similar.

we usually use egatube if all else fails

We have a simple set of rules for outside cabling...

1. No joints

2. use plastic heavy duty conduit

3. we use galv posts and thread up the inside for beams and cams

4. use underground ducts (we have a cool machine that digs 4" trenches on its own)

5. any flexi is done using the metal armoured stuff

6. seal behind, cable entry, top and sides of beams but leave bottom to drain

7. tin the ends of the cables with solder

tip: if using optex beams take them apart and fill the top of the lense part (the bit that moves) with clear silicon, then it will never mist or fill up with water!