Interruption or damage to the electricity supply

Continuity of an electrical supply was of paramount importance during the war as it was vital for domestic consumers as well as the industries that relied on it for the war effort. The records in The IET collection focus on how staff maintained a supply of electricity in hostile environments.

power stations

Power stations worked continuously but the black-out restrictions meant staff had to work in difficult conditions and often in darkness. A keen ear was required to identify any changes in noise output indicating a problem that was not picked up as an abnormal reading on a gauge.

During a state of emergency each member of staff had an important role to play. If enemy aircraft in the vicinity meant a decrease in the amount of load required from a station, due to factories stopping output while danger was imminent, then instructions were quickly signalled to the boiler attendants. They would then slow down the fans, ease off the coal supply to the furnaces and reduce the steam pressure. All this had to be carried out even while enemy aircraft were flying overhead.

procedures for reporting damage to power stations

A collection of papers relating to the Metropolitan Borough of Stepney (NAEST 001/02/712) concerning the operation of electricity supply and reporting on damage during wartime conditions gives a first- hand account of what staff had to be prepared for during this period.

There were several procedures power station staff had to follow in the event of disruption or damage to electricity supply. The first being the speed at which notification was given and the chain of communication they had to follow.

Firstly, they were obliged to notify the Commissioners under Regulation 21 of the Electricity Supply Regulation 1937, by the earliest practical post, of failure of supplies or damage to works.


“In view of the local or regional action which may have to be taken, particularly in the event of hostile attack…the Ministry of Home Security regard it as essential that the earliest possible notification of interruption of supply or damage to electricity works should be available to the local A.R.P. organisation and hence to the regional organisation concerned, through which the Ministry of Home Security itself will be kept informed of the position in the various Civil Defence Regions.”

IET Archive NAEST 001/02/712 p.8 16 May 1940

This communication was later superseded by an instruction dated 30 May 1940 stating that in the case of all Electricity Undertakings notification had to be made direct to the London Regional Headquarters.

IET Archive NAEST 001/02/712 p.7 30 May 1940

There was also a clear set of information that had to be relayed irrespective of whether the damage had been caused by hostile action or by other causes not arising from the war.  The information that had to be reported was,

  • the time, date and location e.g. Generating Station or substation,
  • the cause of damage or failure,
  • the approximate extent of the interruption to the supply, in particular to any vital industrial establishment or to any substantial section of the population affected,
  • the estimated time a complete or partial restoration of supply could be made.

To ensure consistency in the messages special forms were created.

[IET Archive NAEST 001/02/712 pp.10-11]

An example message might read as,

“Limehouse Generating Station hit by E.H.T. bomb 11.00 hours. Minor damage to plant, station output restricted to 31 M.W but restoration expected within 48 hours. Supplies not affected. Three employees wounded. 11.10 hours.”

The instruction sheet given out by Mr Campbell, Metropolitan Borough of Stepney Electrical Engineer and Manager, ends with the reminder that this information is of a secret nature and it should only be disclosed to “responsible officers whose duties necessitate them being in possession of this knowledge.”

IET Archive NAEST 001/02/712 p.9

If a G.P.O. [General Post Office] call was required for Central Electricity Board work, priority was given if these exact words were spoken,

“Central Electricity Board speaking. Electricity breakdown, urgent call to (required telephone number) wanted by (our telephone number).”

The word “Priority” should not be used.” 

repairing damage to cables

It was equally important to repair damage to cables that were often caused by enemy action or defence guns. Notification needed to be reported quickly to a team of staff at the Power station or sub-station who would then go out to try and rectify it in all kinds of adverse conditions. Lorries with the initials RP/E could be seen which stood for Repair Party-Electricity. Under normal circumstances some repairs would have taken up to 36 hours but under special A.R.P. (Air Raid Precautions) conditions and using emergency materials this time could be reduced to as little as 12 hours. Maintaining an electricity supply was essential therefore staff and engineers would endanger themselves by going out in the middle of the night, driving in black-out conditions in unknown territory, often in dangerous conditions, to repair damaged cables and ensure the continuity of the supply.