Q & A of the Day – Do these external CCTV and lighting supplies need surge protection?

Question: I understand that surge protection should be installed at the mains incomer and locally to key pieces of critical equipment, such as computers etc.

However, is there a requirement to provide surge protection on external equipment supplies, such as CCTV cameras, lighting columns etc?

Answer: Surge protection may be provided as one solution to provide protection against overvoltages that occur because of atmospheric origin, or due to switching (Section 443 of BS 7671), where it has been deemed necessary. It may also be installed as a measure to reduce electromagnetic interference again where deemed necessary (Section 444), but there is no specific requirement to provide surge protection!

Where surge protection has been deemed necessary by the designer of the installation, this type of device should be selected and erected as per section 534.

As you indicate in your question, this may be both at the origin of supply and possibly downstream adjacent to sub-distribution equipment, and possibly even locally to equipment where a specific level of protection is desired.

The reasons for deeming this type of protection necessary may be because of the equipment manufacturer's specification - i.e. manufacturers instructions requiring surge protection, or it may because of the outcome from a risk assessment - i.e. if there is a possibility of damage to the equipment by lightning strike, or if the possible consequences of this occurring are severe. Examples include potential loss of life, loss of service, high cost to the building owner.

Where lightning protection might be the reason for you considering this surge protection, I recommend that you contact Furse, a company that publishes a very useful free guide to BS EN 62305-4.

To see many more Q & A in Voltimum UK's Experts Area, please click on the link: