Ask the experts/Technical
Fully charged Providing basic protection Objective In some cases EICR codes (C3 and even C2) have been attributed to the presence of exposed live parts within consumer units and distribution boards even though it is not possible for the user of the installation to make contact. This article looks to clarify the requirements for Basic Protection at boards and similar equipment.
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eedback from the Technical Helpline shows that in some cases classification codes have been recorded on the Electrical Installation Condition Report (EICR) which identify a risk of contact with live parts at consumer units, distribution boards or similar equipment, even though basic protection is provided by the enclosure (the external casing). This article outlines the requirements of BS 7671 for the provision of basic protection using barriers and enclosures to provide protection against the risk of contact with live parts at consumer units, distribution boards and similar equipment (which in this article are referred to as boards). Barriers or enclosures
Fig 1 Board and busbar covers missing, presenting a risk of contact with live parts
Periodic inspection of low voltage electrical installations should confirm that provisions for basic protection exist to protect persons (and livestock) from contact with live parts (Section 416 refers). Such protection may be achieved by either barriers or enclosures, providing a minimum level of protection of IP2X or IPXXB (finger contact) (Regulation 416.2.1 refers). Additionally, the horizontal top surface of a barrier or enclosure which is readily accessible should also provide a degree of protection of at least IP4X or IPXXD (Regulation 416.2.2 refers). Basic protection for boards is normally provided by the enclosure as long as it satisfies one of the following requirements listed in Regulation 416.2.4: • removal of a barrier or opening of the enclosure is not possible without the use of a tool or key, or • provision of an intermediate barrier removable by the use of a key or tool to remove the barrier, providing a degree of protection of at least IP2X or IPXXD which prevents contact with live parts, or • removal of a barrier or opening of the enclosure is only possible after disconnection of the supply to the live parts contained within the enclosure. Removal of a barrier or opening of the enclosure is not possible without the use of a tool or key
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Gaining access into most boards requires the use of a tool or key. Therefore, where the enclosure is in a satisfactory condition, not damaged or corroded, the user of the installation is unlikely to be at risk from contact with live parts unless blanks are missing from spare ways, unused entries are not suitably closed, or used entries do not provide the minimum IP rating required by Regulation 416.2.1.
Spring 2016 Connections
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05/04/2016 11:55