IEC 60364-7-710 Standard: Low voltage electrical installations

The standard classifies medical areas into three groups, according to electrical risk:

NOTE 1: An intracardiac procedure is a procedure by which an electrical conductor is placed inside the heart of a patient of a patient or is liable to come into contact with the heart, this conductor being accessible from outside the patient’s body. In this respect, an electrical conductor is understood to mean both insulated cables such as stimulator electrodes or intracardiac electrodes for ECGs (Electrocardiograms), as well as electrically insulated tubes with conductive fluids.

In Group 2 areas, electrical systems in IT configuration with isolation transformers conforming to IEC 61558-2-15 must be used. These systems allow continuity of supply to be maintained in the event of a first insulation failure, thus reducing the risk to the patient. It is mandatory to have an insulation monitoring device (IMD) according to IEC 61557-8 and additionally a fault location detector according to IEC 61557-9.

Electrical equipment which has an applicable part or which transfers energy to or from the patient or which senses such energy and transfers it to or from the patient and which:

1. Is provided with not more than one connection to a particular power supply network; and.
2. Is intended by its manufacturer to be used:
   • In diagnosis, treatment or monitoring of a patient; or
   • For compensation or relief of disease, injury or disability.

NOTE 1: ME equipment includes those accessories defined by the manufacturer that are necessary to enable normal use of the ME equipment.

• IT Regime Systems with Isolation Transformers

In Group 2 areas, IT-regime systems, which incorporate isolation transformers in accordance with IEC 61558-2-15, must be used. These transformers provide galvanic isolation, reducing the risk of electrical faults in earth fault conditions.

• AC-DC Isolation Monitoring Devices (IMD)

IT systems must be equipped with insulation monitoring devices that continuously monitor the insulation resistance between active conductors and ground. These devices must comply with IEC 61557-8, and the associated fault location detectors must comply with IEC 61557-9.

• Automatic Source Transfer (ATS) Devices

To ensure continuity of power supply, especially in critical areas, automatic mains transfer devices can be used that automatically switch to a backup power source in the event of failure of the main source. These devices must comply with IEC 60947-6-1.

• Certified Distribution Panels

All of the above equipment must be integrated into distribution switchboards certified to IEC 61439, which establishes requirements for the design and verification of low-voltage switchgear assemblies.

Emergency Power Requirements

IEC 60364-7-710 establishes the maximum times allowed for switching to emergency power supplies, depending on the type of load: critical or essential.

• Critical loads (vital functions)
  

  An uninterruptible power supply (UPS) capable of taking over the load in a time ≤ 0.5 seconds, guaranteeing supply for at least 2 hours (or 1 hour if there is a generator coming into operation later) is required.

  Examples: life support equipment such as respirators, monitors and surgical lamps.

• Essential loads

  A switching time of between 0.5 and 15 seconds is allowed, provided that a generator capable of supplying power continuously for a minimum of 24 hours is activated.

These response times ensure operational continuity in medical facilities, especially in critical areas where interruption of the power supply can put patients’ lives at risk.