Neutral and Equipment Grounding Conductors

[zemingduan]

Hi guys, here is my question: can one grounded wire work as both neutral conductors and equipment grounding conductors?
The situation is that: An old wiring that has 2 hot and 1 bare(uninsulated) grounded overhead feeders connected from the service equipment to a detached building's panel. I understand that 250.32(B)(1) says the neutral and equipment grounding conductors can't not bond together at the equipment other than the service equipment bc it will cause the neutral current flow on the equipment grounding conductors and result in overheating, nuisance tripping of ground fault protection, etc... But in this situation, they don't have separate neutral and equipment grounding conductors. If the one grounded overhead conductors are sized to able to carry the neutral current and ground-fault current, is this allowed by code or previous version NEC? I didn't find the code that solves this problem.

 

[ActionDave]

The installation you describe was legal until the 2005 version of the NEC as long are there were no metallic paths between the structures. There is an exception for existing installations.

 

[zemingduan]

The installation you describe was legal until the 2005 version of the NEC as long are there were no metallic paths between the structures. There is an exception for existing installations.

Thanks! Here is the exception.

I saw this exception previously but just didn't understand what the exception is talking about until I read your reply and read this exception again.