Perry, please see my attached drawing. I highlighted in pink what I interpreted as you telling me to connect the DC out to the ground at the wall. Please let me know if this setup will work and if not how to fix it. I also added the Arduino in there with a relay (which I'll do after making sure it is good without the relay. I use a switch to turn everything on and off. The Arduino is physically isolated from the high power side and has its own separate 9V power supply.
I find it odd to connect the 24V DC out to the ground at the wall. This wont trip my breaker?
In response to your previous post, our 'neutral' wire is connected to the ground at the transformer outside. It has a ground conductor that brings it back to the transformer. It is at or near ground potential even when it is live. As far as I know the ground part of our plug is actually connected to the ground.
Thanks
As far as I can see that's fine.
I find it odd to connect the 24V DC out to the ground at the wall. This won't trip my breaker?
Correct, it won't. There is no circuit that the breaker is involved in to trip anything. Doing this is for safety, in the event that, for example, the transformer insulation breaks down then any resulting leakage will be grounded and your breaker should trip. You should connect the 0V of the Arduino circuit to ground for the same reason. If you project ends up in a metal case you should connect the case to ground as well.
In response to your previous post, our 'neutral' wire is connected to the ground at the transformer outside. It has a ground conductor that brings it back to the transformer. It is at or near ground potential even when it is live. As far as I know the ground part of our plug is actually connected to the ground.
I would expect neutral and ground to be connected somewhere, that's what makes neutral neutral. That does not mean neutral can be used as a ground connection for at least 2 reasons:
1. Assuming you have earth leakage protection (I think you have from what you said) the leakage current needs to bypass the earth leakage breaker in order to trigger it. The neutral goes through the earth leakage breaker so any leakage back through the neutral won't trigger the breaker.
2. The neutral in the return path for current in the live wire after it has gone through whatever you are powering, so the neutral is connected to live via lights, heaters, TVs, whatever. In the event that the neutral becomes disconnected, maybe because of a loose connection, then the neutral becomes live and it no longer safe.