MDPE or Copper through the wall ? Best option

[Cross90]

I'm currently trying to complete bringing water into my garage and cant seem to find an answer as to what is best practice.

Bringing 20mm MDPE up the ouside of my garage wall, is it best to use a 90bend bringing the MDPE through the wall and then use a reducer to change over to 15mm copper pipe

...or...

Bring the 20mm MDPE up the outside of the wall, then use a reducing 90bend to change over to 15mm copper pipe ?

I know it would be best to avoid bringing it up the outside of the wall all together, but the foundations of the house & garage are both raft, so this isnt an option. I plan on lagging all the external pipe along with installing some trace heating with a inline thermostat running at both ends to the bottom of the 750 trench.

Cheers

 

[PrenticeBoyofDerry]

I would go with MDPE entering the building then, if you wish continue in either plastic or copper when reducing.
It maybe have to factored in, if the garage has electrics installed that if the pipe is entering in a metallic pipework, that will then require bonding.