Introduction to Health and Safety at Work

Figure 12.4
Modern 
multiplug.

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Introduction to Health and Safety at Work
192
The use of electrical equipment in potentially 
fl ammable atmospheres should be avoided as far as 
possible. However, there will be many cases where 
electrical equipment must be used and, in these cases, 
the standards for the construction of the equipment 
should comply with the Equipment and Protective 
Systems Intended for Use in Potentially Explosive 
Atmospheres Regulations 1996, known as ATEX. Details 
on the classifi cation or zoning of areas is contained in 
the Dangerous Substances and Explosive Atmospheres 
Regulations and ACOPS.
Before electrical equipment is installed in any 
location where fl ammable vapours or gases may be 
present, the area must be zoned in accordance with 
the Dangerous Substances and Explosive Atmosphere 
Regulations and records of the zoned areas must be 
marked on building drawings and revised when any 
zoned area is changed. The installation and mainten-
ance of electrical equipment in potentially fl amma-
ble atmospheres is a specialized task. It must only be 
undertaken by electricians or instrument mechanics who 
are trained to ATEX standards.
In the case of a fi re involving electrical equipment, 
the fi rst action must be the isolation of the power supply 
so that the circuit is no longer live. This is achieved by 
switching off the power supply at the mains isolation 
switch or at another appropriate point in the system. 
Where it is not possible to switch off the current, the fi re 
must be attacked in a way which will not cause additional 
danger. The use of a non-conducting extinguishing 
medium, such as carbon dioxide or powder, is necessary. 
After extinguishing such a fi re careful watch should 
be kept for renewed outbreaks until the fault has been 
rectifi ed. Re-ignition is a particular problem when carbon 
dioxide extinguishers are used, although less equipment 
may be damaged than is the case when powder is used.
Finally, the chances of electrical fi res occurring 
are considerably reduced if the original installation 
was undertaken by competent electricians working to 
recognized standards, such as the Institution of Electrical 
Engineers’ Code of Practice. It is also important to have 
a system of regular testing and inspection in place so 
that any remedial maintenance can take place.