Power Transformer CT with No Insulation

[wsscott]

This is from the 1947 Oahu Tonemaster I've been working on.  Here's a photo of the bare CT lead.

Has anyone ever seen a CT for a power transformer that's just a bare, braided wire, like this connecting to ground?

Seems weird to me.  I'm having some hum and can't figure out where its coming from.

[passaloutre]

I’ve seen transformer frames grounded like that. Are you sure it’s the CT. I would’ve thought the yellow wire next to it was the CT.

[tubeswell]

Could be a Faraday shield grounding lead

[wsscott]

Thanks.  I've concluded it's a ground of some sort but not the CT.  It would have been nice if the wires were of different colors.

[passaloutre]

Of the wires coming out of that hole, I’d be willing to bet the black ones are primary, the twisted reddish yellow are the secondary, and the lone yellow is the center tap.