Outside Lights RCD Question

[Petersto]

My mother has recently moved into a new build apartment block. The car park has pillar lights around the outside which is fed by two separate circuits. Recently one circuit started tripping the 30mA RCD the instant they were scheduled to turn on. After contacting the electrician for the development his solution was to remove the circuit from the RCD (leaving a large gap in the consumer unit where you touch the bus bar no problem!). When I asked him why he'd removed the RCD he cited that the outside lights have electronic ballasts which would always trip an RCD and it shouldn't have been put on it in the first place!

After he left, both circuits started tripping the 10A MCBs. He returned some weeks later and went though the wiring finding a non waterproof connection letting water in which caused the problem.

After finding the cause for the RCD and MCBs tripping he refused to put the circuit back on the RCD

As I understand, (from my rather limited knowledge) 17th edition regs require new installation to be protected from an RCD, is this not the case?

 

[DaftPunk]

Providing the lights are fed in SWA cable, then an RCD is not required, and it sounds like this circuit would be better off without one.

 

[ericmark]

559.10.3 Protective measure: Automatic disconnection of supply
559.10.3.1 where the protective measure automatic disconnection of supply is used:
(i) all live parts of electrical equipment shall be protected by insulation or by barriers or enclosures providing basic protection. A door in street furniture. used for access to electrical equipment. shall not be used as a barrier or an enclosure
(ii) for every accessible enclosure live parts shall only be accessible with a key or a tool. unless the enclosure is in a location where only skilled or instructed persons have access
(iii) a door giving access to electrical equipment and located less than 2.50 m above ground level shall be locked
with a key or shall require the use of a tool for access. In addition. basic protection shall be provided when the door is open either by the use of equipment having at least a degree of protection of IP2X or IPXXB by construction or by installation, or by installing a barrier or an enclosure giving the same degree of protection
(iv) for a luminaire at a height of less than 2.80 m above ground level, access to the light source shall only be possible after removing a barrier or an enclosure requiring the use of a tool
(v) for an outdoor lighting installation. a metallic structure (such as a fence, grid etc.), which is in the proximity of but is not part of the outdoor lighting, installation need not be connected to the main earthing terminal.
559.10.3.2 It is recommended that equipment such as lighting arrangements in places such as telephone kiosks. bus shelters and town plans is provided with additional protection by an RCD having the characteristics specified in Regulation 415.1.1.
559.10.3.3 A maximum disconnection time of 5 s shall apply to all circuits feeding fixed equipment used in highway power supplies for compliance with Regulation 411.3.2.3 (TN system) or 411.3.2.4 (TT system).
559.10.3.4 The earthing conductor of a street electrical fixture shall have a minimum copper equivalent cross-sectional area not less than that of the supply neutral conductor at that point or not less than 6 mm² whichever is the smaller.

Reading those rules on street furniture it would seem only recommended to have 30ma RCD but will need to comply with IP2X or IPXXB and the hole in the CU will clearly not comply.

 

[Petersto]

Reading those rules on street furniture it would seem only recommended to have 30ma RCD but will need to comply with IP2X or IPXXB and the hole in the CU will clearly not comply.

Thanks for that, very useful!


Would private car park lighting be considered street furniture?

 

[ericmark]

I would say yes as ordinary persons have access. But definition is here.

Street furniture. Fixed equipment located on a highway.
NOTE: Street furniture includes street located equipment.
Street located equipment. Fixed equipment located on a highway, the purpose of which is not directly associated
with the use of the highway.

The use of 30ma RCD in domestic is for buried cable less than 50mm in wall or ceiling and sockets under 32A plus bathroom non of these are covered in what you describe.

The 12.5mm max hole size is likely exceeded with the removal of the RCD in the board and also any cover used must require a tool to remove so the cut to length plastic cover would not be any good as can remove without a tool.

Isolation may be another problem.

559.11.3 Transformers and convertors
559.11.3.1 A safety isolating transformer fur an extra-low voltage lighting installation shall comply with BS EN 61558-2-6 and shall meet at least one of the following requirements:
(i) The transformer shall be protected on the primary side by a protective device complying with the requirements of Regulation 559.11.4.2
(ii) The transformer shall be short-circuit proof (both inherently and non-inherently) and shall be marked with the Symbol:

559.11.3.2 An electronic convertor for an extra-low voltage lighting installation shall comply with BS EN 61347-2-2.
NOTE: A convertor marked with the following symbol should be used.

Missing signs are:-
1 Transformer - short-circuit proof (both inherently and non-inherently)
2 Electronic convertor for an extra-low voltage lighting installation (inverted triangle with 110 marked in it.)
In other words they have to isolate.

Other than holes left in consumer unit I would think you have little you can do. Although there are rules they are not law although can be used in a court of law. Also remember anything to do with health and safety must be written. Text message or Email will do but if some one gets injured and you say I told XXX but did not back it up in writing you can be found libel. Not like contract law health and safety must be in writing. At least at work it has to be not sure about when not employed but I would play safe and do it in writing.