These are strange days aren’t they? it seems like we are
living through some sort of science fiction film like “The Andromeda Strain”.
And when you add in the whole world (or pretty much) being locked down as well
it gets even more weird. I think most people can now see why we have been so
concerned about biological warfare. So far, I have lost two uncles and a cousin to this wretched
disease. It gets scary when it gets close to home like that. I’d like to know if “Extinction Rebellion” will be flying out
to China to stage demonstrations and demand that the Chinese keep their
disgusting diseases to themselves? I also think the Chinese should pay reparations to the rest
of the world for the havoc they have caused, and it’s not as if they didn’t
have enough warnings with SARs etc. I have been more than busy with gardening, home maintenance
and office work, the funny thing is I’ve still got loads to do! I do have a weakness for the odd glass of vino (red is my
poison) and usually manage to contain it until the sun is over the yardarm. On
these sunny days though an al fresco lunch with a glass of lager in the garden
is very enjoyable. It amuses me to see how some people are struggling to stay
in close company with their partners. That is the price to pay for being desperate
to settle down too quickly, my advice is take your time and make sure you
actually know and like that person (and that is reciprocal) before tying the
knot. The furthest I’ve been this month is to the bottom of the
garden. Which by bloody good planning (and good luck) we sectioned off the
bottom part last year and turned into our own “Allotment”. This has given us
plenty to keep us occupied and will soon be giving us food as well. My “person of merit” this month must go to our Prime
Minister. What a start to a new job! As if taking us through Brexit wasn’t
enough. I’ve seen some pretty nasty comments about him being hospitalised and it
always seems the nastiest remarks come from those who are supposedly
liberal/socialist. Says it all really. Those that have cheesed me off more than ever recently have
been the media. I am becoming more and more revolted by their biased views and
desire to wallow in negativity. How often do we good news in the media? And how
about this, at the start of this epidemic a few people starting getting stupid
and panic-buying. So what do the media do? Give maximum coverage to this and
create a mad rush to the shops! I would really like to see a return to the days when we just
got the news. During the wet days of our confinement I have been making an
in-depth study of the changes brought in to the 18 Edition by
Amendment 1. That in turn, has made me make more of a study of electric
vehicles, which doesn’t really appeal to me that much. However, I am now pretty
well versed in this area and feel quite confident to pass this knowledge on.
What I will say though, is that in my opinion, the contents of Part 722 are far
too detailed for the average sparky and should be incorporated into the
requirements for equipment, not the requirements for installation. I think we
are in danger of the regulations becoming a tome that will be impossible to
lift up let alone comprehend. For example, lets just take a moment to reflect and find our
way through the woods. In the Annexe to Part 722 in the 18 Edition
the following formula is recommended for finding current in the neutral for a
three-phase system. This formula appeared in the 17 Edition as
well.  So if we take a 3-phase system with the following loads –
75A, 52A & 43A, using this formula I came up with 28.5A (Im). Not being
much of a mathematician though it took me a bloody long time to work it out.
So, not trusting myself it did the old tried and trusted vector diagram and
measured it to be about 26A, so I know I’m in the ballpark. However, there is a much easier method of figuring out
current in a 3-phase system un-balanced system (where all have the same phase
angle) and that is to quite simply subtract the lowest figure from the highest.
In the above example 75 – 43 = 32A Simples!
Now I know its not as exact as by calculation but its close enough for a
quick assessment and as a method to check your calculation. Current in the neutral is always a difficult quantity to be
precise with anyway due to harmonics and load variations. All we can say with
any confidence is that for a resistive system, current in the neutral will not
exceed the highest loaded phase conductor. I don’t think I’ll be undertaking any training again until
the beginning of July at the earliest. From a personal point of view, I don’t
know if I would feel confident then or not. I suppose all we can do is wait and
see. But I do think that when the world comes back to life it
will be mayhem with people catching up with everything – work, training,
holidays, new kitchen, new car etc etc. I should know, I’m going to be up the
front with the rest of them! Adios chums, until next month. |
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