Commercial Office Power Circuits, Safety

In the latest UK 2015 electrical regulations there has been an improvement to safety for power (13A sockets) circuits in commercial environments. For a new circuit it is more difficult to justify not using a RCD (Residual Current Device)  safety device in addition to the normal Fuse/Miniature Circuit Breaker. RCDs generally are considered a device that protects persons from accidental electrical shock. Whereas Fuses and Circuit Breakers protect against circuit overload that for example could either result from a live wire accidently touching earth or lessor level of overload that could cause a fire.

RCDs are a significant improvement to electrical safety but surprisingly in commercial (office) environments they have not been installed a commonly as one might expect.  Besides the fact the previous regulations did not demand an RCD should be fitted so to save money they were left out, there also has in the past been a concern that numbers of computers on one circuit with an RCD could trip accidently with very unfortunate consequences.

RCD devices are now more readily available for three phase commercial Distribution (fuse) Boards and at more reasonable prices.  Also careful design of the number of sockets on a single circuit can avoid the problem of accidental or nuisance tripping out of an RCD.

In the depths of our winter is the time when office staff may bring in from home or buy extra portable heaters for use at their desks.  Particularly with electrical installations without RCDs this would be a very unwise practice.  The office provided equipment would only be plugged into circuit that was designed for that use and that equipment would have been PAT tested regularly anyway.  If a non PAT tested old heater is plugged into a socket that was intended for low power electrical load and does not have an RCD, then it can result in safety issues.

A few days ago I attended on a fault where an office user reported a smoking and sparking 13A socket outlet.  In this case there was a portable heater plugged in and the heater had been PAT tested.   But the circuit with everything else plugged in was just into overload levels which in turn had stressed what was probably a loose connection in the wiring. The connection had overheated and burnt the back of the 13A socket and wiring.

Those in small businesses responsible for requesting and engaging electrical maintenance should  perhaps make enquires as to whether RCDs are installed on the office 13A sockets, ensure PAT testing is undertaken regularly, do not allow non business provided heating equipment to be plugged to office 13A circuits and importantly when arranging the Periodic Testing of the office electrical installation ensure that part of the brief is for a realistic sample of the wiring connection screws to be checked.


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