WN |
PLACES OF WORK – NEW INSTALLATIONS |
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| WNQ1 |
The 17th Edition requires socket-outlets rated at up to 20 A and intended for use by ordinary persons to be provided with additional protection by means of a 30 mA RCD. Many socket-outlets in offices may be considered to be subject to this requirement. However, many offices will have computers producing protective conductor current, individually and/or collectively. This accumulated protective conductor current could cause the circuit RCD to operate. Such disruption will not be acceptable to the office users, particularly in banks etc. How can such unwanted tripping be avoided? |
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| WNA1 |
Where additional protection by RCD is necessary, unwanted tripping can be avoided by appropriate sub-division of circuits.
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314.1, 531.2.4. |
| WNQ2 |
Which 13 A socket-outlets in commercial and industrial premises are required to have additional protection by RCD? |
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| WNA2 |
Socket-outlets in commercial and industrial premises must have additional protection by means of an RCD if they are rated at 20 A or less and are for general use without the supervision of a skilled or instructed person. An exception is made for a specific labelled/identified socket-outlet for a particular item of equipment.
The decision as to which socket-outlets are provided with RCD protection in accordance with these criteria should be made in consultation with the client’s duty holder under the Electricity at Work Regulations 1989.
As a general principle, it may be considered that socket-outlets in commercial and industrial premises needing to have additional protection by means of an RCD include the following: those in common, circulation and public areas; those in self-catering areas; those intended for use by cleaners; and those that may reasonably be used to supply mobile equipment for use outdoors.
See decision tree
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411.3.3 |
| WNQ3 |
Which socket-outlets in commercial and industrial premises are NOT required to have additional protection by RCD? |
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| WNA3 |
Socket-outlets in commercial and industrial premises must have additional protection by means of an RCD if they are rated at 20 A or less and are for general use without the supervision of a skilled or instructed person. An exception is made for a specific labelled/identified socket-outlet for a particular item of equipment.
The decision as to which socket-outlets are provided with RCD protection in accordance with these criteria should be made in consultation with the client’s duty holder under the Electricity at Work Regulations 1989.
As a general principle, it may be considered that socket-outlets in commercial and industrial premises NOT needing to have additional protection by means of an RCD include the following: a socket-outlet labelled for the connection of a specific item of equipment; socket-outlets not intended for general use, such as those in floor service boxes intended for the connection of workstations and other IT equipment; socket-outlets for use under the supervision of skilled or instructed persons so as to minimize the possibility of careless use.
See decision tree
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411.3.3 |
| WNQ4 |
How do I decide what grade and/or type of fire alarm and emergency lighting systems should be provided for a commercial property? |
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| WNA4 |
Reference should be to the applicable Building Regulations, BS 5839-1 and BS 5266 which give specific recommendations.
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| WNQ5 |
If an RCD is used to achieve automatic disconnection within the prescribed time, is the supplementary bonding called for in 411.3.2.6 still required? |
411.3.2.2, 411.3.2.3, 411.3.2.4 |
| WNA5 |
No. An RCD is a valid way of complying with automatic disconnection requirements.
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411.4.4 |
