TNAG-0767-FCO40-971-Supplies-of-electrical-power-for-Hong-Kong-Castle-Peak-power-1978 — Page 125

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reduce the possibility of faults, by reintroducing periodic testing of electrical installations. The Director of Public Works is discussing means for implementing this with the power companies. By the time the first increase in the voltage is introduced, considerable progress should have been achieved. On the other hand, 220 volt equipment run on 220 volts will involve slightly less heating of wiring than 200 volt equipment run on 200 volts. So overall in the longer term there should be a slight reduction in the risk of fire;

(e) certain organisations will be particularly

badly affected. The Telephone Company claim that to replace equipment that could not operate on the higher voltage would cost them $5.8 million (made up largely of air conditioning plant, supply units in subscribers' premises and some exchange rectifiers, all of which are alleged to be voltage sensitive). If this assess- ment were to turn out to be correct, the cost would ultimately be borne by subscribers; but there could be at least partially offsetting savings in that future equipment will no longer have to be manufactured specially for 200 volts. For the Government, there will be capital expenditure which could be as high as $5 million, to provide new voltage regulators for stand-by generators whose existing regulators allow for a change of voltage of only ± 2%.

The reasons for not changing to 230 volts

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The reason for considering a change to 230 volts rather than to 220 volts is that the International Electro Technical Commission has recommended 230 volts as a future world standard. It is not much more than a recommendation on paper at the moment, with only 20 countries have adopted it in practice so far. At least in the foreseeable future the disadvantages of changing to 230 volts are:

(a) for the power companies: that they could not

effect the change using their existing equipment;

(b) for consumers generally: that generation at 230 volts is associated with a tolerance of 10% to give a range of 207 - 253 volts. The higher end

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