Out of Africa - Electrics

One of my tasks whilst visiting J&S in Kenya was to install lighting and a 13A outlet in the new school room. Some allowance had been made during the building work, so there was already a conduit from a 13A socket in the adjacent church to the roof space above the school room.

This post is about what I learnt about Kenyan wiring and some confessions.

The incoming supply is overhead from a roadside pole where only two wires are visible. As far as I could tell, then, the earthing system is 'TT' i.e. the protective earth is supplied by the customer and there is no explicit connection to the supply authority's earth.

I learned that, as a rule, red = Live, black = Neutral, green/yellow = Earth. And that all domestic carcass wiring is done in 20mm black plastic conduit. I say "as a rule" because apparently rules are there only to be broken.

Incoming supply switch-gear

You can click on these images to enlarge them. The picture shows the supply authority's switch-gear which is mounted in a rough metal enclosure on the outside wall of the church. The incoming supply is the black (coaxial?) cable entering at the top and terminates in the DIN-rail double-pole switch at left. This is turn connects to the HXP100DIM metering module via scarily thin wires possible only 2.5 sq.mm. This module has a twin wire data connection to a coin-slot meter inside the church. The supply connects from here to the larger switch on the right where it is joined by an earth cable presumably connected to the customer's earthing rod.

There is a thoroughly normal consumer unit inside the church building with several MCB's which supply lighting and power outlets.

Showing the incoming supply cable in the angled conduit

You'll see that nothing is properly fastened to anything - the supply authority's conduit is roughly supported at a crazy angle only by the geometry of the wall.

Church socket wiring, with my spur connected

Within the church, which is in effect a large single room, there is what I take to be a ring circuit running around the perimeter. It runs in conduit under the plaster but becomes visible at periodic conduit boxes none of which are fitted with lids. For all that effort I could find only two double 13A sockets on this ring, both on the platform. One was hanging (not screwed in). The other (shown above) was properly fastened and was where the provided conduit to the school terminated.  You'll see from this that the colour scheme adopted is:

Green/yellow = Live, green/yellow = Neutral, red = Earth.

In spite of that unfortunate choice the wire gauge appears to be correct i.e. 2.5 sq.mm for Live and Neutral.

My wiring uses the correct Kenyan colours and can be seen connected as a spur in the above picture.  We purchased our wire by the metre at a hardware store in nearby Chavakali.  Here I specified 2.5 for power and 1.5 for lighting, and the store (and I) judged the correct gauge by the larger outer insulator diameter for the supposed 2.5 sq.mm. However when I started working with this wire I found the outer diameter to be a lie, as shown below where I latter compared with wires stripped from Irish 2.5 sq.mm T&E cable.  The bare copper earth wire at top is thus 1.5 sq.mm.

It would appear that the Kenyan green/yellow and black "2.5" is indeed 2.5 sq.mm but the red "2.5" is in fact much less, perhaps 1.5 sq.mm.  And of the two lighting gauge wires at bottom right only the red one is really 1.5, the black being significantly less maybe only 1 sq.mm.

Comparison of wires

Did this matter?  Given the sloppy nature of the wiring generally, our reluctance to go source the correct gauge, and the fact that the two new lights were rated 35W each and that the single double-socket would be used at most only to charge electronic computing equipment, I reckoned not.

According to Irish code an unfused spur from a ring circuit is not allowed, also not allowed is a direct connection from a ring circuit to a reduction in wire gauge for lighting. But I committed both sins, in addition to the wrong wire gauge I had been duped into buying.

But at least all my wiring was in conduit and used the correct colours. Whereas at J&S's house, which had been wired by a "professional" electrician, the conduit stops a few inches short of lighting fixtures so you have single-insulated wire bridging this gap, albeit sometimes wrapped in insulation tape for good measure.

Oh, and when the plumber came to connect a tap to the rainwater tank we had installed, he needed mains power for his electric "welding" machine for PPR water pipe.  An extension cable was not to be had. Indeed his complete tool set consisted only in this rather ancient machine and a couple of plumbing wrenches. We had to supply hack-saw, pipe and fittings, lunch and a drink. So I used some of our recently purchased black lighting wire, connecting into his machine's 13A plug at one end and splicing into the ring main in one of those exposed conduit boxes at the other end, there not being a 13A socket within reach. It did the job, though would hardly have passed health and safety.

School days

My older sister was my childhood mentor.  Three years my elder it was she who "held my hand" on my very first day at primary school.  Many years later I asked what happened in secondary school and she told me about "boring" subjects like physics - when I asked her was physics was she told me it was about heat and light and electricity, which to me sounded most interesting!

My first school was Alresford Preparatory School run by a "the thin Miss Curtis" aided by her sister (who was not, I think, trained as a teacher) "the fat Miss Curtis".  This was a dame school with all 30 or so students studying in a single room.  The school was closed down by modern idealists not long after I graduated.  I regret that I cannot find any old photographs, so the best I can do is this one I took recently - apologies to whoever lives here now.  The location is a yard opening off West Street.

The school room was upstairs.  Access was via the door you see - it has not changed.  Under the staircase was the "closet" (toilet).  Students were discouraged from using this facility, I suppose for fear that it would detract from their studies.  I remember several occasions of younger inmates asking to "go" and it being denied.  The inevitable result was also not greeted with enthusiasm.  As the years went by you progressed from the west (entrance) end to the east end of the room, and from the "fat" Miss Curtis to the "thin" Miss Curtis.  No-one liked the "fat" one.  The "thin" one was strict but at least rational.  The "fat" one was highly unpredictable.  One one occasion she arrived at school with her hair dyed bright orange, and we are talking about middle-aged sisters here.

'A' for Apple, 'B' for Bucket, 'C' for Cat, 'D' for Domino, 'E' for Engine, 'F' for Feather, 'G' for Gate, 'H' for Hat, 'I' for Ink, 'J' for Jug, 'K' for Kite, 'L' for... and here my memory fails me.  Possibly 'Lamb'.  I can still visualise some of the pictures on the cards.

As expected I got my 11 plus but only after the second attempt.  I had the chance to take it twice because of birthday, I did not and still do not understand the details.  After failing my father told me I needed to work harder, a concept that had not occurred to me before this point.  I suppose I duly obeyed and passed, and thus an entrance was gained to me to Peter Symonds grammar school, Winchester, and later to Oriel College, Oxford.

The preparatory school was highly predictable.  Every year me made chinese lanterns and crocus cards to exactly the same design.  For what seems always we wove raffia to make what turned out to be (to my great surprise) a place mat.  And we wound wool around an annular card former.  Eventually this became fat enough and it was whisked away and re-appeared the next day, wonder of wonders, and a fuzzy bobble.

There was a stuffed fox in a glass show-case on a shelf at the east end of the room.  Under this shelf was a piano and a Miss Cob (Cobweb to us) gave us music lessons once a week.  We would sing such English delights as "Early one morning" and "and the green grass grew around, around, around" (of which I have since learnt the somewhat different Irish version).  I remember the time when I "noticed" that the piano playing involved an accompaniment as well as a melody - and remember acknowledging how good it sounded and how amazing something so good should emanate from the cobweb.

There were wonderful, coloured maps on the walls - one had the Caspian Sea marked on it, which name enchanted me.  My eyes explored every line on these maps.  Maps still hold a place dear to my heart.  And there was time to dwell thus: for example at a certain and totally predictable time of the week we would do "paper work" (origami to you).  An instruction might be to fold the paper along a diagonal.  This I accomplished in a few seconds then looked around to see where my peers were at.  The considerable amount of time and teacher intervention that some of these required to achieve a result of poorer quality still amazes me, but gave me plenty of time for contemplation.

At the west (entrance) end was a pot-bellied stove, the only source of heat.  I cannot remember anyone getting burnt - children, on the whole, have enough sense - all this modern nonsense of putting guards up everywhere to make things "safe" is hugely overdone.  I was regulation in those days for all school children to each be provided with a 1/3 pint of milk in a returnable glass bottle.  These were delivered in a crate and on cold, winter's mornings the milk would arrive frozen solid.  The crate would be placed beside the stove and the contents were consumed, I suppose, at break time half-way through the morning.  Often the milk was still half frozen by that time and, when mention was made of this, I remember the fat Miss Curtis declaring that it was "just like ice cream".  My confidence in grown ups was totally devastated by this blatant and manipulative falsehood and has never really recovered since.