Did I wire this correctly?
My understanding is that strapped wire (green/yellow) is ground, so I connected it to the middle. And blue/brown doesn't really matter which way they go, since for alternating current positive/negative doesn't really matter.
The flip side of the plug above
And the original stock plug that I'm replacing
Best Answer
Normally we do care about hot vs neutral, even though they are AC. That is because the system is designed so neutral is near earth potential, so it is essentially non-hazardous except if something has failed. Machines are wired with that in mind, for instance a screw-base lamp will wire neutral to the more-easily-touched shell.
However, your particular plug type is designed to be symmetrical - it can be flipped over, reversing hot and neutral. This defeats the purpose of separating hot and neutral, and therefore requires a double insulated appliance. If the air conditioner originally had a keyed plug, this might matter because it might not be double insulated. The good news is the machine probably has a metal chassis, which will at least protect you from shock - if your ground wire is solid as a rock! If it's not, an insulation failure could energize the chassis of the machine.
If you can't ground the machine reliably, GFCI aka RCD will greatly reduce that risk.