Handbook of Electrical Installation Practice - BeKnowledge

22 Handbook of Electrical Installation Practice
Fig. 1.7 Typical service entry into a house.
flat itself. None of these is ideal as each fails to meet one of the following requirements:
capable of being read by the consumer, capable of being read by a meter
reader without entry to premises, not observable by persons with malicious intent
(no movement of the meter might give an ‘all clear’ to a break-in), allow a prepayment
meter to be used. This latter possibility was not an attractive one from the
local DNO point of view as the collection of the money was a big problem. Fortunately,
the development of token meters has solved the problem of theft. Trial
schemes have been so successful that existing money prepayment meters are rapidly
being replaced by token meters; 25000 were installed in London alone in 1988. Each
token meter has a unique key identified with a consumer, which is recharged at
streetside vending machines; hence the keys have no intrinsic value. Load and
address data stored in a key’s memory chip can be recovered by a vending machine
and used for load analysis purposes.
In each case the meter position is decided on which factors are important and
which disadvantages can be overcome.
In high-rise buildings electric heating can simplify the construction and be an
economic solution but the interdependence of the heating gives problems of