This follows on from a prior question and discussion: Cable size between equipotential earth bonding bar and distribution board in a Group 1 medical location

Regulation 710.415.2.3 states: The EBB shall be connected to the system earthing using a protective conductors having a cross-sectional area greater than or equal to the largest cross-sectional area of any conductor connected to the EBB.

Note HTM 06-01 provides no further definition of the point of connection of the EBB and the connection to the systems protective earth.

The clause is silent on the location; however, the consensus was:  the local Distribution Board  rather than the origin suffices.

Question 1 : The following statement has provided by a hospital engineer questioning this. Is this considered a user preference rather than regulatory compliance:

''Where practicable, medical equipotential bonding should be connected directly to the main earthing terminal to ensure integrity and clarity of the earthing system. 

 Risks of wiring EBB to a DB;

•  Increased dependence on downstream connections
• Higher chance of unnoticed disconnection
• Harder inspection and fault tracing
• Greater lifecycle risk
• You are relying on the DB & MET connection
• Any future alteration, loose termination, or undocumented change can ;Increase impedance/break the bonding path
• The EBB is a safety reference, not just a CPC
• Increased impedance & higher touch voltages under fault conditions
• DBs are: Opened/modified/extended & re-terminated
• During future works: Earth Bars get disturbed/conductors get moved or resized/Temporary disconnections occur
• The medical equipotential system can be compromised without anyone realising
• Parallel earth paths and circulating currents cause issues with testing

 Direct MET connection provides a solution that is as follows;

• Lowest risk
• Clearest compliance
• Preferred by healthcare AEs on a new project 

Question 2 : From the statement above is this statement correct:  The EBB is a safety reference and not just a CPC