John's Jottings

136. The Doubtful Daisy-chain - October 2017

Posted on October 1, 2017 at 6:00 AM

On arrival at the Wraybury show with our layout, we found that no electrical cables had been laid out, even though setting up was well under way.

“You’ll find a socket somewhere over there,” one of the organisers said, with a gesture that was wide enough to encompass most of the known universe. “You all have your own way of setting out cables, so we’re letting you get on with it.”

We erected the layout and ran out our cables. Then Ken took the plug end of our heavy-duty extension lead and went in search of a socket. He soon reported back that he’d plugged it into a bank of socket two layouts away, and it would soon be live.

In the meantime, the operators of the layout on the other side had asked if they could plug into our multi-gang socket. Of course they could. And the layout next to them daisy-chained from their power supply. But as opening time rapidly approached, not a single layout had any power to carry out the essential tests of their electrical systems.

Another of the organisers wandered by. “When’s the electricity coming on?” we asked him. He didn’t know, but said he’d sort it out.

He traced the cables right round the exhibition hall. Eventually he reached the end plug. “I’ll soon have you all connected,” he shouted triumphantly. “I’ve just got to find a socket.” He hunted round and found one underneath a layout. “Power going on,” he cried out. “Have fun!” We waited, and waited, but nothing came live. The chap disappeared.

Out came the test equipment. The continuity of the wires within the cables was frantically investigated. The integrity of fuses was examined. Plugs were opened up to check that all wires were firmly screwed into the correct terminals.

Then the hunt for the missing electricity really started. We sent out two search parties. One set off clockwise, the other anti-clockwise. Between them they traced the sequence of connections from under one layout to under its neighbouring layout. The two search parties drew ever closer to each other, but on the other side of the hall. Eventually they met at a micro-layout.

“Where’s your power supply,” they asked the operator.

“Dunno,” he replied. “I’m battery-powered. There’s this cable passing underneath.”

In desperation, a plug was pulled out from a socket. Having checked that the socket was dead, one probe of the test meter was held against the earth pin of the plug and the other pushed into the earth aperture of the socket. The meter bleeped unhealthily. But it bleeped. The same thing happened with the neutral and live.

“We have continuity right round the hall,” Ken announced. “But at no point is any of it actually connected to the mains.” There was laughter amongst the exhibitors.

By now the organisers were wondering why no locos were running, no display lights were on, and no sounds were coming from the DCC layouts. Then the penny dropped. There was a frantic search for some additional extension cables, and an even more frenetic hunt for the building’s own wall sockets. Eventually the great circular daisy-chain was divided into sections, and each connected to a live outlet. The layouts sprung into life just as the doors opened and the public streamed in.

“Does it not go to demonstrate,” our chairman wondered, “that every aspect of an exhibition should be planned, and those plans put into operation? When it comes to something as critical as the power supply, nothing should be left either to chance or for exhibitors to sort out for themselves piece-meal. Yes, there will always be deviations from any plan, but there must be an effective plan to begin with.” We all agreed with him. It remains to be seen whether the organisers get their act together in time for next year’s show.

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