As a surveyor in the construction industry (and having worked in both imperial
and metric in the UK, the US, Canada and South Africa), something about this
story doesn't quite ring true.
1. In-the-field tolerances are never less than 1/16 imperial (1.6 mm), or 1
mm metric (at least I've never
Dear John,
I noticed the closeness of 2.52 inches and 64 mm and then I wondered
whether they were trying to fit a metric cable into an old- pre-metric
space or vice-versa.
On another issue from the same article, I wondered about where in
Italy you could buy a 2 inch cable. This would be
Hi Pat:
I believe (any electrical experts here that could confirm this?) that cables
are all based on a rational progression of their (metric) cross sectional
areas. Even the cable to my electric kettle is shown in terms of its mm2
value. I would imagine that the 2 inch value is a (rough)
I agree that getting people to use the SI is most important. That's
why I suggested, a few years ago, the local school system of nearly 140,000
students teach and use the SI. They now are doing it.
I only was trying to point out that within the medical industry, there
should be
I had much the same thought as you. One simply doesn't try to put a 2.52
cable in 2.52 hole or trench. Since they are now putting in a 2 cable, it
needn't be a tight fit. Of course, the story is filtered through a reporter
who is perhaps innumerate.
Also, 2.52 seems like such an odd
John, Pat
Whereas you and I are used to systems that use 230 V, most readers of this
forum are used to using 115 V systems and as a result the regulations are
probably different. Also, if the trench was made of steel, would air
cooling be needed - steel is probably much better. Having said
Martin:
I would think that these cranes would run on something like 405 V (or 435 V,
I've forgotten which), which is the voltage that lifts/elevators operate on in
North America. 115 V (actually, normally 110 V) would be much too low a
voltage to run a dockside crane on.
Cheers
John F-L
