22.04.2008
Up to now the ESB has used Electromechanical meters for the majority of whole current metering installations. In 2007 Meter Asset Management entered into a new metering contract with suppliers which resulted in the use of electronic meters right across the whole range of metering requirements.
Heretofore, for multi-metering panels electromechanical meters were utilised. For Day/Night multimetering panels there was a requirement for the use of a combination of electromechanical two rate meters, timeswitches and interposing relays at the multi metering panel as described on pages 32 and 33 of the present code book. With the introduction of electronic meters this requirement has now changed.
Electronic meters as now supplied for Day/Night installations have an integrated timeswitch in the meter, and also have the facility of an auxiliary contact which will close on night rate. This auxiliary relay is rated at 230V AC and 80mA Max.
For all new Day/Night multimetering panels therefore, there is no need for an external timeswitch or relays at the metering panel. The requirements for the mains wiring will remain as before. For NSH control, it is essential that the operating current of the coil in the control relay in each apartment does not exceed 80mA. Control cables for each apartment are to be brought directly to the meter.
As before, control cable to be labelled with apartment numbers at file terminals and meter positions and the colour code of the control wiring is to be brown and white. Where the control pair is brought directly from the apartment to the meter it is acceptable to use a twin brown, but the cable must be identified with the apartment number and the live and switch wire must be clearly identified at the meter position. Control pair (1.5sqmm) to be fused appropriately in each apartment.
Note: If the operating current of the coil exceeds 80mA, then there will be a requirement for the panel manufacturer to provide separate interposing relays for each apartment at the meter panel, whose coil does not exceed a current of 80mA. Note also the 80mA max rating relates to the inrush/starting current of the relay coil.
NB: The foot print of the single phase meter is unchanged and the present space allocations must not be reduced. This is to allow future exchanges or metering upgrades.
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Related contacts
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Register of Electrical Contractors of Ireland,
Unit 9, KCR Industrial Estate,
Ravensdale Park,
Kimmage, Dublin 12.
Tel: 01 - 492 9966
Fax: 01 - 492 9983 |
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Source: RECI Winter 2008 Newsletter |
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