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RCD Protection for CCTV

Heera

Hi all,

I have a question if RCD's are required for 230v CCTV Cameras. 

1. It is a TT system, resistance values unknown and not tested.

2. CCTV is fed from a 6A (MCB), SP&N DB, directly to a PSU which sits above the metallic camera column

3. Load is around 1A

4. Cable is 2.5mm singles within the metallic camera column, therefore daggling inside it. 

Question is: do I require an RCD? Lightening protection has been risk assessed out, as it it not needed. If there is a break in the mains cable feeding the PSU, do I require an RCD? Resistance values from two points are less than 50ohms. Unfortunately an earth mat cannot be installed or electrode. 

The client has also requested a CPC to the metallic column, but the main cables are protected. Is this the same principal as earthing a metallic back box within a domestic installation? I have looked at the BS761 regs for the answer, and I'm guessing as it's LV it may be required?

Please can someone advise?

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  • 0
    Heera said:
    I have a question if RCD's are required for 230v CCTV Cameras. 

    The design should be conducted by someone who is competent and experienced with the particular location(s) in which the cameras are being installed, especially if members of the public can access the column.

    From your description of the earthing arrangements, an RCD appears likely to be needed for automatic disconnection of supply according to Chapter 41 of BS 7671, although knowledge of the 'resistance values' that are 'unknown and untested' would be necessary to complete the design in any case.

    There are also cases in which BS 7671 requires additional protection by 30 mA RCD for safety (e.g. Regulation 411.3.4 for installations associated with dwellings, Section 714 for outdoor lighting and street furniture accessible to the public). The designer might also choose this for safety, after considering safety of the installation according to relevant legislation.

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  • 0
    Heera said:
    I have a question if RCD's are required for 230v CCTV Cameras. 

    The design should be conducted by someone who is competent and experienced with the particular location(s) in which the cameras are being installed, especially if members of the public can access the column.

    From your description of the earthing arrangements, an RCD appears likely to be needed for automatic disconnection of supply according to Chapter 41 of BS 7671, although knowledge of the 'resistance values' that are 'unknown and untested' would be necessary to complete the design in any case.

    There are also cases in which BS 7671 requires additional protection by 30 mA RCD for safety (e.g. Regulation 411.3.4 for installations associated with dwellings, Section 714 for outdoor lighting and street furniture accessible to the public). The designer might also choose this for safety, after considering safety of the installation according to relevant legislation.

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