ACShielded Xformer Mystery Wire

Hi all,

I found a few lower power shielded transformers at a flea market, and they do 120 to 40 CT VAC, so perfect for small bipolar power supplies.. They're steel-shelled with 4 mounting screws on the bottom and the transformer is potted into the shell, so I can't get a look at it without destroying it.

There's 6 wires coming out of it, the 5 identified and a mysterious grey one which is insulated from all the others ( inf. ohms) but reads

5 different voltages ranging from 2.8 - 65 VAC when measured against each of the other ones. This one and all the others are insulatd from the case, so its not a case ground wire.

So:

1. Could this wire connect to an internal shield to minimize capacitive coupling or is it something else?

1. If the shield, are these voltage readings normal for such a connection?

2. If the shield, should I connect this wire directly to AC earth ground, or to chassis ground?

I'll just ignore it if I can't figure it out, but if it is some kind of shielding it would be nice to take advantage of it properly.

Thanks for any help.