About to tackle replacing 2 old cracked sockets in my garage and adding in a third. I was going to use plastic sockets and boxes as I like the look of d trunking as opposed to metal conduit.

Looking at the boxes, they have knockouts on the sides and bases, is running out of the top of plastic box a no no? The existing sockets have bodged side entry.

Firstly, you can use metal sockets with plastic conduit. The round stuff actually fits very neatly with proper screw on ends. Metal boxes have knock outs on all sides. Only reason to come from above would be moisture ingress, not really a big deal inside unless the garage is very leaky.

Our workshop…

[url=https://flic.kr/p/pZcnZN]Surface wiring in 20mm PVC pipe[/url] by Ben Freeman, on Flickr

I have all of mine in plastic, I have fitted stuffing glands to all entry points to boxes.
If you have outside lighting, ensure the cable has a droop on it before it enters the wall, on the outside.
If you paint the walls white, use black conduit, its less likely to get hit as you will see it, I didn’t and have hit stuff a few times.

Trunking into metal boxes in my garage. Edit top wired

Plastic trunking top entry into a plastic back box in my garage and the thing was built 2 years ago so must comply with regs. Can’t see why there would be no knockout on top, take a hole saw to it?

Can’t the backboxes go either way up? i.e flip them over so the knockouts are at the top?!