I think I must have a different squirrel cage variant. This one has the contacts on the base of the fan - no wires running anywhere.
To be fair I could have run wires over the top to a spare ground/the adjacent resistor! On reflection that would have been easier but I was a bit concerned about...
Just to say thanks for uploading this! I've used it to replace a noisy squirrel cage and it's a lot quieter now.
I did have to make a small hole in the mount to get through to the original fan's power lines.