You've identified a common point of confusion in the NEC. Let's break it down

Your Analysis is Correct:
The EGC DOES satisfy the requirement of 250.50 in this specific scenario.

Here's the reasoning:1. Understanding 250.32 and the Separate Building

NEC 250.32 deals with grounding requirements for separate buildings or structures supplied by a feeder or branch circuit. It allows for a grounding electrode system to be established at the separate building, and the connection back to the main building can be solely through the EGC. This is a key point.2.

Purpose of 250.50 (Grounding Electrode System)

250.50 requires all available grounding electrodes to be bonded together to form a single grounding electrode system. The primary purpose is to reduce impedance to ground, creating a lower impedance path for fault current to return to the source. This ensures faster clearing of faults and minimizes touch potential.
3.

EGC as the Connecting Link

In the scenario described by 250.32, the EGC serves as the sole means of connecting the grounding electrode at the separate building back to the main building's grounding electrode system (which includes the grounded conductor and all its electrodes). By virtue of being an EGC, this is a code-acceptable ground-fault current path4.

Informational Note No. 1

As you pointed out, the informational note clarifies that the EGC also performs bonding. The EGC bonds all non-current carrying metal parts of equipment together and ties them to the system grounded conductor or GEC at the source.5.

Why an Additional GEC is NOT Necessary

In the situation outlined in 250.32 with only an EGC running between buildings, an additional grounding electrode conductor does not need to be run to bond together the electrodes at each building. The EGC ensures a low impedance path for fault current to return to the source at the main building, satisfying the intention of the code.

In summary

The EGC, in this specific scenario, serves the dual purpose of providing a fault current path and bonding the grounding electrodes at the two buildings together. The EGC is, by design, the code-recognized path to connect the separate building electrodes together.

Important Considerations



Only applies with a single branch circuit or feeder

250.32 applies where a single feeder or branch circuit serves the detached building.

Adequate Sizing of EGC

The EGC must be properly sized according to 250.122 to provide an adequate path for fault current.

Metal Water Pipe Electrode

If the separate building has a metal water pipe electrode, it must be bonded to the disconnecting means enclosure or grounding bus with a conductor sized per 250.66 (This is in addition to the EGC).

The Code Wording, while seemingly contradictory, is actually quite precise when you consider the specific use case of a separate building fed by a single circuit where an EGC is allowed as the sole bonding/grounding path back to the main building.

Therefore, you are correct in your assessment. No additional GEC needs to be run between the separate electrodes to bond together and form a grounding electrode system. Flag for review