Which location the service connection supply leads to be connected at consumer main board?
Answers
Answer:
The main installation CB is located in the consumer's premises in cases where it is set to trip if the declared kVA load demand is exceeded
Answer:
In the past, an underground cable service or the wall-mounted insulated conductors from an overhead line service, invariably terminated inside the consumer’s premises, where the cable-end sealing box, the utility fuses (inaccessible to the consumer) and meters were installed.
A more recent trend is (as far as possible) to locate these service components in a weatherproof housing outside the building.
The utility/consumer interface is often at the outgoing terminals of the meter(s) or, in some cases, at the outgoing terminals of the installation main circuit-breaker (depending on local practices) to which connection is made by utility staff, following a satisfactory test and inspection of the installation.
LV consumers are normally supplied according to the TN or TT system, as described in chapters LV Distribution and Protection against electric shocks and electrical fires. The installation main circuit-breaker for a TT supply must include a residual current earth-leakage protective device. For a TN service, over current protection by circuit-breaker or switch-fuse is required
A MCCB - molded case circuit-breaker- which incorporates a sensitive residual-current earth-fault protective feature is mandatory at the origin of any LV installation forming part of a TT earthing system. The reason for this feature and related leakage-current tripping levels are discussed in Implementation of the TT system.
A further reason for this MCCB is that the consumer cannot exceed his (contractual) declared maximum load, since the overload trip setting, which is sealed by the supply authority, will cut off supply above the declared value. Closing and tripping of the MCCB is freely available to the consumer, so that if the MCCB is inadvertently tripped on overload, or due to an appliance fault, supplies can be quickly restored following correction of the anomaly.
In view of the inconvenience to both the meter reader and consumer, the location of meters is nowadays generally outside the premises, either.
In this kind of installation it is often necessary to place the main installation circuit-breaker some distance from the point of utilization, e.g. saw-mills, pumping stations, etc.
The main installation CB is located in the consumer’s premises in cases where it is set to trip if the declared kVA load demand is exceeded.
In a space inside a building, but with cable termination and supply authority’s fuses located in a flush-mounted weatherproof cabinet accessible from the public way.
The service cable terminates in a flush mounted wall cabinet which contains the isolating fuse links, accessible from the public way. This method is preferred for aesthetic reasons, when the consumer can provide a suitable metering and main-switch location.
In the field of electronic metering, techniques have developed which make their use attractive by utilities either for electricity metering and for billing purposes, the liberalization of the electricity market having increased the needs for more data collection to be returned from the meters. For example electronic metering can also help utilities to understand their customers’ consumption profiles. In the same way, they will be useful for more and more power line communication and radio-frequency applications as well.
In this area, prepayment systems are also more and more employed when economically justified. They are based on the fact that for instance consumers having made their payment at vending stations, generate tokens to pass the information concerning this payment on to the meters. For these systems the key issues are security and interoperability which seem to have been addressed successfully now. The attractiveness of these systems is due to the fact they not only replace the meters but also the billing systems, the reading of meters and the administration of the revenue collection.