REGULATION AND COMPLIANCE
An area of confusion is around the final circuits supplied via the medical IT system. They are not listed in section 710 because the requirements are covered in the standard section of BS7671, part 6, inspection and testing (I&T). Due to the nature of the earthing system a different approach is required to check compliance with the maximum measured permissible earth fault loop impedance values. This is because the system is designed to not disconnect the supply upon the first fault to earth, so values need to be calculated to disconnected upon a potential second fault condition.
The latest iteration of the wiring requirements for electrical installations released by the IET.
additional guidance on special location in their Guidance Note 7 – Special locations. As with all special locations, the section includes the additional requirements over and above the standard wiring regulations. These additional items include a reduction in the voltage present between simultaneously accessible conductive parts (25 V AC or 60 V DC), Isolated Power Supplies (IPS) with a specific earthing system for group 2 medical locations (medical IT systems) and the installation of Equipotential Bonding Busbars (EBBs). These items are not exhaustive of the requirements. The section contains Annex 710 which is a table that lists medical locations and suggests a proposed medical location group. Obviously not all areas can be included so the table should be used as a guide. It could assist a duty holder as a starting point when classification of the group is being determined on an older installation/ area. The requirements for periodic inspection and testing are increased to include the testing of the special location additions. The requirements offer a suggested frequency of the additional tests. These are: n Functional test of insulation resistance monitoring devices (IMDs) associated with the medical IT system – Annually.
n Measurements to verify the resistance of supplementary protective equipotential bonding is within the required limits (EBB connections) – Annually.
n Measurement of leakage current of the output circuit and enclosure of the medical IT transformer – Every 3 years.
The medical IT system final circuits should be listed on an EICR and need to include circuit details and recorded results. In both cases and most importantly, the paperwork needs to include an observation list that identifies if there are any deviations of the regulations present within the installation.
40 Health Estate Journal February 2026
Understanding the requirements Amendment 4 has been designed to help the reader understand the requirements in greater detail. Most of the content has been re worded to make the regulations clearer and to align with the HTMs. Some examples are the inclusion for the requirement for a double pole circuit breaker suppling single phase final circuits from the medical IT system. This regulation is covered in the main body of BS7671 (part 5) but is now included within the special location so all required information for a designer is in a single place. Another great additional is the rewording of the diagrams and document regulation. There has always been a requirement to annually test the continuity of all supplementary protective equipotential bonding conductors, but the wording suggested a different method of testing could be utilised. The regulation now includes the wording to measure the ‘end to end’ resistance of the conductors. Therefore, being very clear that the conductor needs to be disconnected from the EBB before any resistance measurement is taken. A new addition is Annex B710 which is a template report to record the measured results for supplementary protective equipotential bonding system. This sets the standard for the expected information and test results required for the annual tests.
Are you compliant? Many standard EICRs in hospitals and other medical locations do not include the additional requirements for section 710. In many cases, this is due to the duty holders utilising specialist contractors to complete the works required on medical IT systems, UPS and EBB systems. Therefore, the scope of the EICR does not include the I&T of medical IT system sockets and EBB bonding conductors. It is very important for the duty holder to understand the scope of works provided by the specialist contractor as in most cases, the contractor will not complete all items. Research completed as highlighted items stated in BS7671, regulation 710.651(i), insulation monitoring device (IMD) and regulation 710.651(iii), measurement of leakage current of the IT transformer are being completed. The requirements of 710.651(ii), measurement of resistance for supplementary protective equipotential bonding is not being carried out. It was also identified that the EICR requirements for the medical IT system sockets where not be conducted as part of the agreed servicing package. The regulations require an EBB to have a record schedule and test data, along with a diagram to show connected conductors to the bar, with all corresponding information. The medical IT system final circuits should be listed on an EICR and need to include circuit details and recorded results. In both cases and most importantly, the paperwork needs to include an observation list that identifies if there are any deviations of the regulations present within the installation.4 The frequency of the Inspection & Testing is an ongoing debate due to the provided guidance within the industry.
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