Separately derived system connection to GES

[Electron_Sam78]

Does anyone know when the code first required separately derived systems (transformers) to be connected to the building GES?

 

[don_resqcapt19]

Prior to the 1975 code...the oldest one I have.

 

[jaggedben]

I don't know but my guess would be it was always required, at least since any electrode was required.

 

[electrofelon]

I don't know but my guess would be it was always required, at least since any electrode was required.

I am guessing system grounding was a thing long before equipment grounding. So before equipment grounding, the GEC would need to be installed to ground the system - that makes sense, but what doesnt is when equipment grounding came along, why was an additional conductor required? Why not just allow a single conductor to serve both purposes?

 

[jaggedben]

I am guessing system grounding was a thing long before equipment grounding. So before equipment grounding, the GEC would need to be installed to ground the system - that makes sense, but what doesnt is when equipment grounding came along, why was an additional conductor required? Why not just allow a single conductor to serve both purposes?

Because voltage drop can cause a potential to develop between exposed parts? But it never amounts to more than a couple volts so if it's an issue I don't think it's shock hazard.

 

[electrofelon]

Because voltage drop can cause a potential to develop between exposed parts? But it never amounts to more than a couple volts so if it's an issue I don't think it's shock hazard.

But neither the GEC nor the EGC run with the circuit supplying the sds, carry current under normal conditions