I need to change the cord on an electric dryer from 4-prong to 3-prong. My questions concern 1) what to do with the ground when moving to the 3-prong dryer and 2) how to test whether the installation is working as it should using a multi-meter.
The ground strap that the documentation mentions is not present nor is it available. I have fashioned a connection from 10 gauge copper wire. The new installation looks like this:
My research on the wisdom of this connection is all over the place, and I'm very interested in not screwing up. (One electrician I asked told me to connect the middle lead of the pigtail to the ground screw and leave the neutral empty. The most read post on this site says not to connect the ground and neutral. The manual says to use the ground strap, presumably connecting the neutral and ground.)
This is the wiring diagram for the dryer:
This is the original 4-prong configuration:
Thanks for your input.
EDIT: This is the inside of the current dryer receptacle, which is connected to a THQL breaker in the junction box (picture of that in the comments):