BS7671: Section 710 medical locations

BS7671 is the UK low voltage (LV) wiring regulations published by the Institute of Engineering and Technology (IET) in agreement with the British Standard Institution (BSI). The current edition is known as the 18th edition, incorporating Amendment 3. The regulations will be amended in April 2026 with the issue of Amendment 4. Section 710 of BS7671 covers the additional requirements for medical locations. Matthew Gilmore, technical director at Guardian Electrical Compliance, explains medical locations and discusses Section 710 requirements and Amendment 4 updates to help an electrical duty holder meet their legal responsibilities.

What is a medical location?

Section 710 of BS7671 sets out the additional electrical requirements that must be followed when designing, installing, or maintaining systems supplying medical locations. These requirements are mirrored in Health Technical Memorandums (HTM). The HTMs that cover the requirements are HTM 06-01 — Electrical services supply¹ & distribution and HTM 06-02 — Electrical safety guidance for low voltage systems.² The HTM documents refer readers back to BS7671 for detailed guidance.

They apply to a wide range of facilities, including:

• Hospitals.
• Private clinics.
• Dental and medical practices.
• Healthcare centres.
• Designated medical rooms within workplaces (for patient and staff safety).
• Buildings conducting medical research involving patients.

Medical locations are divided into three groups; each defined in BS7671.³ These groups reflect the level of patient risk if the electrical supply were to fail.

Group 0 — Medical location where no applied parts are intended to be used and where discontinuity (failure) of the supply cannot cause danger to life.

Group 1 — Medical location where discontinuity (failure) of the supply does not represent a threat to the safety of the patient and applied parts are intended to be used:

• externally,
• invasively to any part of the body except where Group 2 applies.

Group 2 — Medical location where applied parts are intended to be used, and where discontinuity (failure) of the supply can cause danger to life, in applications such as:

• intracardiac procedures,
• vital treatments and surgical operations.

Patients in medical environments can be more vulnerable to electric shock or equipment failure, therefore enhanced protective measures are required. Factors such as touch voltage potential, supplementary protective bonding, and the selection of a suitable earthing system depend on the classification of the medical location. When planning a new installation, designers must consult with medical staff to agree on the correct group classification for each area. This ensures the installation meets all necessary protection and continuity standards. For existing installations — especially those predating the introduction of the medical location requirements — a detailed assessment should be carried out to assign each area to the appropriate group. Once this classification is in place, compliance with the relevant regulations can then be verified during the Electrical Installation Condition Report (EICR) process.

Section 710 and Amendment 4

Section 710 was introduced to BS7671 in 2011 and was designed to help electrical designers comply with the requirements already set out in the HTMs. The IET offer 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:

• Functional test of insulation resistance monitoring devices (IMDs) associated with the medical IT system — Annually.
• Measurements to verify the resistance of supplementary protective equipotential bonding is within the required limits (EBB connections) — Annually.
• Measurement of leakage current of the output circuit and enclosure of the medical IT transformer — Every 3 years.

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.

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. The statutory regulations, the Electricity at Work Regulations 1989 highlight in regulation 41 and 42 that all systems, at all times, should be constructed and maintained to prevent danger.⁵ This regulation does not provide a frequency. The same applies in the non-statutory BS7671 wiring regulations. Chapter 65 — periodic inspection and testing identify the requirement for ongoing I&T to make sure the installation is in a satisfactory condition for continued service. BS7671 does not provide an ongoing frequency but highlights that the time between I&T can be assessed with the installation usage, type and operation in mind.

The IET Guidance Note 3 — Inspection and Testing is a code of practice that is recognised as a supplement to the wiring regulations. This document does offer information on the frequency of I&T. Table 3.2 — Recommended initial frequencies of I&T of electrical installations, suggests group 0 medical locations are completed every 5 years, and group 1 and 2 medical location circuits are completed annually.⁶ The table includes a note that identifies the I&T frequency for the medical location special location additional items, such as EBBs. As table 3.2 from the guidance note has ‘initial’ in the title, this suggests that the frequency is only for the first I&T after the installation is put into service. Further documents need to be reviewed to establish industry guidance. The IET published the Guide to Electrical Installations in Medical Locations, authored by Paul Harris. This document discusses the misinterpretation of guidance note 3, table 3.2, and includes Appendix 11 to clarify the requirements.⁷ Table A11.1 is titled ‘Recommended frequencies of inspections’, and lists the maximum period between I&T. For group 1 and 2 medical locations it is concluded that the frequencies align with the standard requirements for group 0 locations, and therefore a 5-year frequency is listed.

Electrical safety

Section 710 of BS7671 has now been part of the wiring regulations for 15 years, providing the framework for electrical safety in medical environments where patient wellbeing depends on reliable power and controlled touch voltages. Amendment 4 represents an important evolution of these requirements — improving clarity, aligning the regulations more closely with HTM 06-01 and HTM 06-02, and introducing the new Annex B710 report template for EBBs. For duty holders, this amendment sets clearer expectations for testing, documentation, and record-keeping, helping to standardise the way compliance is demonstrated across the healthcare sector. Amendment 4 emphasises that EBBs and medical IT systems must be inspected and tested in accordance with defined standards — not just for compliance, but for patient safety.

The frequency has been researched, and industry guidance has identified that the final circuits supplied via the medical IT system should be I&T every 5 years. This aligns with group 0 locations and enables a duty holder to include the group 1 and 2 medical IT system final circuits to be completed in the same programme of works for the general installation. The frequency for the special location items, such as EBBs, is reduced to an annual I&T.

Conclusion

Guardian have developed a structured two-stage I&T process. The 1st Stage provides a full condition assessment, schematic drawings, and asset documentation, ideal where little or no existing data is available. The 2nd Stage adds detailed end-to-end resistance measurements and connected equipment identification to meet the full requirements of BS7671 and the new Annex B710 expectations.

By following this methodology, duty holders gain full visibility of their EBB installations, with complete documentation suitable for internal audits and regulatory inspections. Whether integrated into a wider EICR programme or completed as a standalone project, this ensures that medical locations remain safe, traceable, and compliant with both the letter and intent of BS7671 Amendment 4. Through this structured and evidence-based approach, this service continues to help healthcare organisations meet their legal obligations and uphold the highest standards of electrical safety in patient care environments.

References

1 NHS England (HTM 06-01) Electrical services supply and distribution [Internet]. www.england.nhs.uk. Available from: https://www.england.nhs.uk/publication/electrical-services-supply-and-distribution-htm-06-01.

2 NHS England (HTM 06-02) Electrical safety guidance for low voltage systems [Internet]. www.england.nhs.uk. Available from: https://www.england.nhs.uk/publication/electrical-safety-guidance-for-low-voltage-systems-htm-06-02.

3 IET — Requirements for Electrical Installations, IET wiring regulations 18th Edition, BS7671:2018:a3. Stevenage The IET 2022.

4 Roberts A. The requirements for protection against electric shocks in medical locations [Internet]. Professional Electrician. 2025 [cited 2025 Dec 4]. Available from: https://professional-electrician.com/technical/the-requirements-for-protection-against-electric-shocks-in-medical-locations.

5 Health and Safety Executive – Electricity at Work regulations 1989, Norwich TSO 2011.

6 IET – Guidance Note 3 — Inspection and Testing. Stevenage The IET 2022.

7 Harris P – Guide to Electrical Installations in Medical Locations. Stevenage The IET 2017.