Health Sector

Safety principles in health facility power supply

In France, in order to prevent accidents from happening and to ensure the safety of the people living in social or medical facilities, a regulatory framework (see French Directive « Circulaire DHOS/E4 n – 2008-114″ – of April 7, 2008 regarding the prevention of power shortages in health facilities) obliges every facility to ensure in the event that the national network is down, there will be service continuity for at least 48 hours. Hospitals and care centres, therefore, have a backup power supply to mitigate for every event.  This back up network is generally made up of a diesel generator, combined with converters and batteries and is of great strategic importance, but is also particularly sensitive. The law therefore requires that the diesel generator be checked every month in mock load and at least twice a year in real load on the network. The reason behind this test is to avoid power cuts to critical equipment ensuring hospital patient safety and well-being, such as fire detectors, safety lights, lifts, etc.

The law provides that these installations must be powered by Secure Power Supplies in compliance with the standard NF S 61-940. These Secure Power Supplies can consist of battery packs, as per Annex A of standard NF S 61-940, or diesel generators in accordance with standard NF E 37 312 :

« A backup diesel generator can be used as a secure source provided it complies with standard NF S 61-940 and that the power required to ensure all fire safety equipment is available to start and operate is sufficient. When the replacing source combines different generators, shall one fail, the power available shall remain sufficient to ensure all fire safety equipment can start and operate. »

The best way to test the diesel generator without impacting on the service’s quality – interrupting the sensitive units, memos, etc. – is to proceed with the generator’s maintenance on a load bank. The load bank will replicate the load emanating from the hospital’s equipment – lift, medical equipment, etc. – and will confirm that the diesel generator is capable of taking over in the event that the main network is down.

These tests performed by a maintenance team or directly by the hospital’s technical team are fast and very efficient. They are often combined with the generator’s maintenance and allow the fix to be approved. Generator manufacturers such as SDMO, Cummins and Genelec, highly recommend that the generator is activated every month for a few minutes.


Applications in the health sector


  • Load banks for regular checking of the backup generator
  • Load tunnel for ballasting diesel generators
  • Testbed for unloading batteries
  • Testbed for converters


Which bank should be used for a generator in a hospital, health centre or nursing home?

  • The load bank should be able to replicate the increase in the diesel generator’s load: a lift starting, surgical equipment being turned on, etc.
  • The load bank should be able to handle the impact and unballasting of quick loads, and its power should be at least similar to the diesel generator’s power in order to be tested at its full capacity.


Key documents on safety in hospitals


  • French law : Annexe à la circulaire Circulaire DHOS/E4 n -2008-114 – du 7 avril 2008
  • French law : Article R6111-22 sur la sécurité des établissements de santé en cas de défaillance du réseau d’énergie