Archived report · 4 min read · Set in Fenchurch Street ·
The Electricity That Visits
A building draws no load overnight, yet every clock inside keeps perfect time and the meter turns backwards once, exactly, each night.
- filed: "At the reading, mid-month"
- reference: "FS/MR/19"
1. Report from the metering office at Fenchurch Street, filed at the reading for the current mid-month, on the overnight behaviour of the office building's own supply, continued under this reference from the re-fit and prior to it.
2. The building is a four-storey switch house with the metering hall below street. Outside working hours the supply is certified dead: the load schedule closes the nursecall, the lift and the hall lights at lock-up, and every circuit one to forty-one reads open at the night board. Since the re-fit certified the closing contactor, the overnight draw of the building on the main meter is, in the meter's own register, zero. The register does not accumulate overnight. This is not in dispute and has not been for three years.
3. In the same three years, every clock inside the building has kept the time.
4. The clocks are electric, of the impulse type, driven from the master panel on the landing. The master is wound by the mains and scored by the pips, and with the mains dead from lock-up to the morning shift it has nothing to drive it and no current to correct it. Yet at dawn the master is found reading to the second against the exchange, and the forty-one secondary clocks on the office floors, none of which have been climbed since the re-fit, read with it.
5. The anomaly that carries this file is the meter's disc. Once a night, and only once, the main meter turns backwards: one full revolution, at speed, in the interval of a little over half a minute. It does this at the same minute each night, inside the third hour, and the register is not affected by the turn. The reading is taken at mid-month as the tariff requires, and the reading, the office records, is always correct.
6. The office therefore took instruments to the anomaly. A chart recorder was coupled across the meter leads. On the night of the backward turn the recorder drew a clean nil line for the whole of the dark hours with one feature: a single square-wave pulse, of the supply's own full voltage, lined up square with the turn to within the width of the pen. The pulse lasts as long as the turn and does not repeat. With the closing contactor proven open, and the schedule certified, there is no circuit in this building through which that pulse was drawn.
7. The office then wound the master by hand at lock-up on three nights and left the mains open. In the mornings the master had unwound itself exactly. On the third morning the winder's own tally-book, left on the landing, was found open at the tally page with the pencil laid flat across it, and the last tally struck through, and struck through in the manner of someone who has made a mistake in a column and does not want it carried down.
8. Enquiry was made of the exchange and of the sub-station that feeds the street. No record, no draw, no switching in the third hour — their logs at that hour are, the sub-station clerk wrote back, the cleanest in the district, and he has stood at the master board on the third hour and watched the district meters, and in his words the street sleeps well.
9. The register arithmetic closes to the day and always closes to the day, and the tariff man signs the sheet monthly, and the reading, as the file has it, is always correct. What is not correct is the order in which it becomes correct. The building takes nothing overnight. The clocks keep the hour regardless. Something meets the meter once a night and the meter turns once backwards under it, and in the morning all the columns are straight.
10. Recommend the reading be continued and the recorder left in place. The chart team has begun to file the nightly pulse by its minute and by nothing else, and the minute of the pulse has moved six minutes inside the hour since the spring, at a rate the office has been asked to watch rather than to question. The reading closes open.