Dear All

The colour coding of plugs is historical and was divised by Estates to denote which sockets were on Essential supply (i.e. those which are connected to the generator in the event of power failure)

i.e. Red sockets or red inserts were for essential medical equipment i.e. connected to the back up generator

Black sockets or black inserts were for all other essential equipment i.e. connected to the back up generatoe

And white sockets or white inserts were for domestic or non essential equipment, i.e. socket not connected to the back up generator

This was done to ensure that the load to the generator is kept as low as possible.

RS supply plugs marked for Hospital Use in three colours, Red, Black and White for this reason. Speak to your Estates of even NHS Estates before adopting any other colour code as you could going against the NHS agreed policy.

I recall MDA had a notice many years ago reinforcing this colour coding for essential mains outlets.