Thought I’d put this in the newbie forum, as it was a newbie-style mistake 
Got a call last night, could I go into local dairy and take a load out - only a short run, 2 drops and back. The regular driver hadn’t made it in. No problems, off I scooted, checked in, got my lorry and trailer details etc and off I went.
Found the trailer, slid underneath, split coupled, remembered to disconnect the electric lead (fridge on electric for once). Did all my checks, and ready to move off. In gear, let the handbrake off and tried to move forwards. Nothing doing.
Got out and checked everything again, and found a pinprick in the red airline - thought it seemed a bit odd, but thought maybe this is why the brakes aren’t coming off. Uncoupled, put that uinit away with a VOR, and got another unit.
Coupled up again, checked, all OK, pulled away, and struggled to get a couple of feet, before I stopped and went round everything again.
Lines all on and good, trailer brake off, no reason as to why the trailer wouldn’t move, except that there was a black mark on the yard from every trailer wheel. Something definitely not right…
Had a look underneath and started to follow the air pipes along the length of the trailer, and wondered to myself why they went in and out of the box where the electric lead plugs in…
Look properly inside the box, and realise that there’s an interlock - when you plug the lead in, you have to move a lever out of the way, which locks the brakes on. Moved the level back, and hey presto, suddenly I could move off! It’s at that point I remember being shown this on my induction
At least nobody was about to take the ■■■■, and I’ll know for next time…
Gary
