You're asking a very nuanced question about 250.68(C)(1) in the 2017 NEC. Let's break it down

Understanding 250.68(C)(1)
General Rule

250.68(C)(1) generally requires that if you're using an electrode (like metal water pipe) as a grounding electrode, the connection of the grounding electrode conductor to that electrode must be accessible. This is so you can inspect and test the connection.

The Exception

The exception to 250.68(C)(1) creates an opening for interior metal water piping systems to be used as a connection to the grounding electrode. It provides an allowance if the metal water pipe system is electrically continuous with the grounding electrode conductor and all portions of the piping system that may be energized are bonded to the equipment grounding system.

Your Question: Piping as Bonding Conductor, Not Electrode

Your question is: If the interior piping doesn't qualify as an electrode (no portion in the earth), can it still be used as a bonding conductor if it meets the exception criteria?The Answer: YES, with a VERY IMPORTANT CAVEAT

The exception to 250.68(C)(1) primarily addresses the connection to a grounding electrode, NOT the suitability of the piping system for general bonding purposes. If the piping is used to connect to a grounding electrode and it meets the requirements of the exception, then the accessibility requirement is waived. This means you don't have to have an accessible connection to the water pipe where the grounding electrode conductor connects. If the piping is used as a bonding conductor for other purposes (e.g., bonding metal enclosures, equipment, etc.), it MUST still meet all other applicable bonding requirements elsewhere in Article 250. This includes things like: 250.92 (Bonding Metal Piping)

This section requires bonding of interior metal water piping likely to become energized, and addresses the sizing and methods of connection.

250.104(A) (Bonding of Piping Systems and Exposed Structural Metal)

This covers the bonding of metal water piping and other metallic systems that may be subject to energization.

Suitability

You need to ensure the piping itself is physically capable of carrying the fault current it might be subjected to. This typically means it needs to be electrically continuous and mechanically robust.

Proper Connections

Bonding connections need to be made with listed connectors suitable for the purpose (grounding and bonding).

In Summary

The exception to 250.68(C)(1) allows interior piping (even if not an electrode) to be a connection to the grounding electrode. The exception waives the accessibility requirement of the connection if all the exception criteria are met.However, you MUST still comply with all other bonding requirements in Article 250, like 250.92 and 250.104(A). Meeting those requirements ensures the piping system is adequately bonded to handle fault currents.

In practice, if your piping is used as a connection point to a grounding electrode, the exception to 250.68(C)(1) addresses that specific situation, and doesn't automatically qualify the entire piping system for general bonding purposes. You MUST separately assess and ensure compliance with the other relevant bonding rules. Flag for review