250.54 vs 250.58

[metdross]

Scenario: Factory is installing supplementary grounding electrodes at each machine connected to EGC as dictated by 250.54
Question 1: "If" conditions are right(variables in EGC, length, size, etc. and soil conditions throughout plant) could these supplementary rods create a separate path to ground?
Question 2: Do the "Supplementary Electrodes" of 250.54 conflict with the "Common Elecrtodes" of 250.58?

 

[petersonra]

Re: 250.54 vs 250.58

Why would one care about a "separate path to ground"? Current flow on the EGC is what is bad. Think about all the conduit and pipe and other metal things in a plant that are interconnected to ground, EGC, and your various grounding electrodes.

The important thing is to have but one main bonding jumper. As long as earth and the grounded conductor (aka - neutral) are connected at only one point, it is fine.

What would be bad is if one were to connect neutral to ground at the service point, as it is supposed to be, and than connected neutral to ground again somewhere else in the plant. BTW, this is not an uncommon thing to see, even though it is forbidden and dangerous.