X0 bond strap

[CapitanMurica]

Doing oil sampling the other day I noticed the X0 bond strap on the transformer was lifted off of the tank. There was a solid ground on the tank in another location, so I asked the site electrician about it and he said there was a reason why they did it but couldn't recall the details, something about it being bonded inside the building. Has anyone seen this before? Is there any reason why you would lift this strap?

[jl8200]

They may do this if it is tied to a high resistance ground or low resistance ground. I don't quite understand if you meant that the X0 was floating or did it have a wire connected to it other than the strap. If they leave it floating then they maybe didn't want a ground reference or some reason.

[CapitanMurica]

It was just a typical ABB 4160-480Y/277 padmount transformer. Now normally on the secondary side there is a bare copper strap that runs from X0 to a bolt on the tank just below the X0 insulator, this strap was connected to X0 but NOT BOLTED to the tank. There was a neutral conductor landed on X0, but nothing connecting X0 to ground inside of the transformer. I found this on more than one transformer.

By the way I am glad someone finally answered my post, thanks!