Fig 2 Responsibility of equipment at the service position (reproduced from the MOCOPA)
8
10
2
7
3
4 5
MAIN SWITCH
6 9
1
DNO EQUIPMENT
SUPPLIER EQUIPMENT
CUSTOMER EQUIPMENT
1 Service cable
4 Meter
6 Meter tails (between meter and customer’s equipment)
2 Cut-out 5 Meter tails (or main or DNO fuse) (cut-out to meter)
7 Customer main isolating switch (if fitted)
3 DNO earth terminal
8 Customer consumer unit 9 Customer earthing conductor (and earth block if fitted) 10 Meter board (or external meter box if fitted)
reported, and where it is identified that the cut-out is loose on the meter board the code B02 should be reported. As explained earlier, this document is primarily for meter operatives. However, Section 3 (Diagram of Equipment Responsibility) of the document will be of use to electrical installation contractors; it clarifies the boundaries of responsibility. Fig 2 illustrates, in accordance with the MOCOPA, which party is responsible for the equipment that Fig 3 Example of a consumer ‘earth bond’ (Hepworth clamp) with the customer’s earthing conductor connected to the Main Earthing terminal
may be found at a typical service position where the supply is TN-C-S. For obvious reasons, the illustration does not express all possible scenarios for equipment at the service position and it is not a wiring diagram for an installation. Contractors should recognise that a potential for change in responsibility exists for part of the earthing system (conductor and earth block). For example, where the supply is TN-S and the distributor originally connected the means of earthing to the lead sheath by soldering or using a unique clamp (known in the trade as a Hepworth clamp, see Fig 3). Where this is the case, code A11 of the document places the responsibility on the distributor (rather than the customer) to repair/ maintain any defects. Where as part of an initial inspection or a periodic inspection, a contractor identifies a defect at the service position, for example, the cut-out is damaged, that defect should be recorded on the relevant certificate or report, and the contractor should inform the customer (owner or user of the installation). Generally the customer, as they are the account holder, reports the defect to their supplier quoting their reference number. Alternatively, the person ordering the work would be responsible for contacting the relevant party to report any recorded defects. Connections Spring 2016
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