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Your Letters

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When's the best time to wash?

When I run the washing machine, tumble drier, dishwasher etc, I wonder if I could reduce the long-term cost of running the grid by simply selecting a good moment to start them. For example, I would normally be happy to wait if I noticed the frequency is under 50Hz. I’d be interested in simple, practical suggestions for when I should start these machines using readily available data such as the wind forecast, one of the real-time grid-monitoring websites or simply the day of the week and time of day.

Peter Sabourin CEng MIET
By email

Foresight of Decca Navigator

I was interested to read the short piece about the Decca Navigator Company in your February 2016 ‘From the IET Archives’ column. My first job in 1955 was with the sister company Decca Radar. Both the Navigator and the Radar businesses came into existence only because of the far-sighted vision of the chairman of the Decca Record Company, Sir Edward Lewis.

Lewis invested in Bill O’Brien’s ideas to create the world’s first accurate navigation system. It worked on land, at sea and in the air. A wide-area version of the navigation system was developed that would have allowed aircraft to fly directly from point to point without following fixed lanes. This was decades before GPS had been thought of. However, the battle with the International Civil Aviation Authority to adopt it as standard was lost. As a result, to this day commercial air navigation is by radio beacons.

After World War Two Lewis also invested in the ideas of Group Captain Fennessy, later Sir Edward Fennessy, to use radar for the navigation of commercial ships. Decca Radar was first in this field and was widely adopted.

John Dakin
By email

Making bullets safer

An important point to remember about expanding or Dum Dum bullets, referred to in recent letters in E&T, is that they were a reaction to diminishing effectiveness. As rifle design improved, bullets got smaller and the muzzle velocity increased. This in turn increased the frictional heat generated in the bullet, causing some lead from the bullet to be deposited inside the barrel, causing fouling.

The solution was to add a cupro-nickel jacket to the bullet to keep the lead away from the barrel, but this reduced its stopping power. British soldiers’ own initiative discovered that scraping off the tip of the jacket to re-expose the lead returned the bullet to its original effectiveness.

Fast forward, and many UK police forces use hollow-point bullets for two main reasons: they are more effective at stopping a bad guy quickly; just as importantly, they are far less likely to over-penetrate the target, and so minimise the risk of an innocent person being hit by accident, either directly or through a ricochet.

So ironically, designing a more effective bullet, is actually the safer option... for everyone except the target of course.

Colin McNulty CEng MIET
By email

No room for bikes in the smart city?

It made me sad to read the editor’s letter in the June 2016 issue of E&T, and Vitali Vitaliev’s article ‘Transport in the Smart City’. The graphic on the front cover set the tone – in the image of the ‘smart city’ we see five cars, the front end of one tram, just four pedestrians, and not a single cyclist. Any idea that a ‘smart city’ would involve the promotion of health and a clean environment by strongly facilitating active travel, walking and cycling, seem an idea way beyond both editorial and article – and just the odd passing reference in other articles in the issue about smart city technology as well.

A key part of a smart city will be space and facilities for a very high proportion of journeys to be made by people in ways that promote health, which means walking or cycling. There’s a minor passing reference to the importance of cycling to modern cities, but nothing whatsoever about walking. Is it hard to think of any way these activities, so helpful and massively important in many of the cities in your ‘top ten’, can possibly connect with technology?

James Larminie MIET
By email

Wiring's tangled tale

Barry Thorpe (Letters, May 2016) confuses standards for electrical installations with compliance and workmanship. That there are bad installations in continental hotels is undeniable; there are also bad installations in the UK, mainly carried out by unregistered electricians.

A European Standard for domestic plugs and sockets exists but will only be implemented when the EU seeks to enforce its use, and there is no stomach for such a change anywhere on the continent. Manufacturers will not readily allow a change from their national sockets, and there is no reason to, other than for the convenience of holiday makers.

As to colour coding, in 1974 the UK, in CENELEC committee TC64, was presented with the fact that it had been agreed that the colour for the neutral should be blue; the Wiring Regulations at that time were not a British Standard and so no-one in BSI consulted the IEE. It is not known which committee or who agreed to blue, but it was probably the machine wiring committee. Product committees dealing with internationally traded appliances wanted a flex which was acceptable in all countries.

We went into the meeting unaware that this was to be raised and in an ad hoc working group (in French) I agreed to blue brown, saying that this was conditional on the fixed wiring (or at least multi-core cable) colours also being harmonised, saying that the colours would be brown, black and white, and I would tell the UK so, which I did.

The number of colours that PVC can be made in is limited. The Germans used red for the protective conductor, the Italians yellow and the UK and Ireland green, so those colours were not available. Orange can be close to red; blue was the neutral and could be confused with mauve or purple. That leaves brown, black, white and grey.

The UK was not interested in harmonising fixed wiring colours and so, towards the end of my chairmanship of TC64, I produced a chart showing what colours the countries had used in 1974 and what they now used; all used brown, black and grey or white except the UK, which still used red, yellow and blue. The Wiring Regs Committee was by then JPEL 64 and they at last took this on board, agreeing after four or five years that it must be brown, black and grey.

There is no evidence of any problems arising for this change, any more than when we changed from red, white and green to red, white and blue and then red, yellow and blue, nor when we changed the protective conductor from brown to green.

David Latimer
Former vice-chairman, Wiring Regulations Committee, former delegate to and chairman of IEC and CENELEC TC64

I recall the reasons for the change in wiring colours were covered at the time in both the popular and technical press, where it was said to be connected to colour blindness. Apparently, the most common form is red/green blindness where those who have it see red and green as a sort of muddy brown. Consequently, they had a 50/50 chance of wiring the earth and live wires the wrong way round, a possible fatal error. The second most common was blue blindness where those who have it see blue as white.

Changing the colours to brown, blue and yellow/green meant that even with no colour vision at all a person could now wire a plug, since they would see a dark grey or black (live), light grey or white (neutral) and candy stripe (earth).

The rock band Hawkwind produced an album at the time showing a plug wired wrongly in the new colours with the candy stripe wired to the live terminal. This caused a bit of a furore in the press, and guaranteed the band some free publicity.

Reid Thomas MIET
Frimley, Surrey

Value of CEng

I take issue with Dr Michael Wrigley‘s claim that CEng status has “very little value in retirement or outside the British Isles” (Letters, June 2016) as the designation has been vital to me both during my working life and retirement. I have worked in most of the countries of Western Europe, Middle East, Far East and USA. I have found CEng recognised and respected in all those countries; I would not have been invited to work on those projects without that higher qualification. I have also found that when trying to obtain redress for defective goods or bad service, signing a letter with the full title gets immediate attention where a plain name does not.

Alan JJ Morris CEng MIET
By email


After a recent visit to Hungary, I returned home to the Netherlands with a mixture of banknotes and coins. I kept this for a visit to the UK by Eurostar last week as I remembered Nick Smith’s article in the April 2016 issue of E&T on the Fourex currency-exchange system and wanted to do a ‘test’. I was impressed by how easy it was to use and was pleased to meet company co-founder Jeff Paterson and two other staff who were there to install German language instructions.

I had a problem with two 10,000 Forint banknotes, but was told that these were new and not recognised by the system. I was given the value in sterling and hope I made a small contribution to extend the range of foreign banknotes.

Simon Duerden MIET
By email

‘Facts’ about CFCs

In your interview with Australian scientist and TV presenter Dr Karl Kruszelnicki (‘Let’s Get Fact’, June 2016), it is presented as ‘fact’ that the hole in the ozone layer was caused by CFCs. Around 20 years ago I remember a column in IEE News warning about the dangers of treating what ‘everybody knew’ as fact. This pointed out some inconvenient verifiable facts that suggested a different cause: there is little mixing of air between the northern and southern hemispheres; CFCs were mostly used in the highly industrialised northern hemisphere, but there is no hole there; Antarctica has an extremely active volcano, Mount Erebus, which continuously emits prodigious amounts of greenhouse gases, suggesting that natural volcanic emissions were a much more likely cause of the hole.

For me the clincher was seeing on TV a sequence of time-lapse photos of Antarctica taken from a polar orbiting satellite. A plume of ‘hole’ could clearly be seen streaming like smoke from Mount Erebus and connecting with the polar ozone layer hole. I understand that a US government-sponsored research project into the impact of Mount Erebus on climate was cancelled before it could publish its report, I wonder why?

Ronald Camp CEng MIET

Education v experience

Frank Everest’s letter in the June 2016 issue prompts me to reply in my capacity as a retired engineer, recently in receipt of an IET 50-year membership pin that I am proud to wear.

I have literally been a ‘one man band’ running my own specialist manufacturing company, and although retired from the payroll for 15 years I keep my eye in by serving on a BSI and ISO committee in our specialised field. Unbelievably I am the UK expert. Not because I have some outstanding ability, but more due to being the only engineer in the UK interested enough to make the effort, it seems.

I have never had to present my membership status or academic qualifications to anybody except to professional institutions when enquiring about entry requirements, and sometimes on official forms. In my engineering world it is something never called for: “Do your products work, and how much?” That’s it!

There is one important point relating to retired engineers and CPD I would like the IET to consider, and that is the creation of an honorary level of CEng that retired IEng members automatically pass to. It is not much to ask in return for a lifetime dedication to the profession.

Strict academic entry requirements that prevailed 50 years ago, where you needed to be blessed with a brain that can remember facts and figures and formulas, ruled me out of the CEng. I was only able to enter at IEng level with an HNC that took 15 years of day release and night school to achieve. There I have been ever since. Laziness on my part you might say, but when it comes to the crunch it is 15 years of self-taught academic learning, parallel to 65 years self-taught engineering embodied in my products.

Cliff Williams IEng MIET

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