Silly question here.
I've wired up a full-wave rectifier using this dual-secondary transformer. If you want to check my wiring, I connected red-to-orange to "create" the center tap (I assume this is OK?), and use black and yellow to provide +/- 24VAC. The center-tap is my circuit ground, obviously. See the rough idea below.
This circuit works nicely. Using some filter caps and linear regulators, I get a nice DC voltage. Everything is as expected. I was running some relatively high current through a load (about 1 amp).
After a few hours of use, I noticed I was getting a "tingly" feeling when I accidentally touched the circuit ground. My multimeter says 77VAC between circuit ground and earth mains! Yikes!
I don't understand how it floated so high above earth ground. I understand that when you have two unconnected grounds, you have no right to expect them to not float with respect to each other.
But, in this case, it seems to me there should be no way for current to flow from myself (at earth ground) to the circuit ground--hence there could be no voltage developed between "us". I thought this was entirely the point of isolation transformers: voltage is developed with respect to each lead of the secondary, but not with respect to earth ground--so one is safe when working with high voltages. My transformer claims 4000VAC dielectric resistance between primary and secondary. So, what is going on here--how could there be such a voltage? And, should I connect earth mains to circuit ground here to fix this--or will I blow a fuse?