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Should fire alarm mains isolators be double pole? This Q & A is one of the thousands posted in our Technical Expertise area and answered by our Voltimum Experts.
Question:
Do fire alarm mains isolators need to be double pole? Is a standard unswitched spur suitable to use?
Answer:
Dan Jackson FIET,
The fire alarm mains isolators do not have to be double pole.
In the latest edition of BS5839 Part 1, the recommendation to provide double pole isolation has been replaced with the recommendation to provide ‘local safe isolation’.
Section 25.2 notes that safe isolation is required under the terms of the Electricity at Work Regulations 1989 [10]. Therefore, any isolator used must have the capacity to provide safe isolation.
Every isolator should be labelled with “FIRE ALARM” or “FIRE ALARM. DO NOT SWITCH OFF”.
The isolator should also be sited in a position inaccessible to unauthorized persons or can only be switched using a special tool that wouldn’t normally be carried by a member of public. A slot-headed screwdriver is not deemed a special tool.