I am sorry for my lack of activity.  I went into a bit of a downer, after not getting a full time teaching job last year.  There is no point in crying ( boo, hoo!) as everyone is going through hard times at present.

I have now shaken myself down and am ready to re-contribute to the world of ‘all things electrical’

Now for this week’s news…… I am handing in my Cert-Ed paperwork on Thursday.  It is all complete after a two year slog!  This means I will be a qualified teacher very soon.  I have also started on a draft of my latest project.  I am going to dissect BS7671 to help all my disciples to pass the exam with ease…….

Bye for now!

Have been doing a little job at the British Legion today.  The club needs a Periodic Inspection so I am helping to make this happen.  I was working on the main distribution board and found something that may be of interest to the to the regular ‘Part P’er’ who doesn’t venture into factories and the like……

Now of course you come across and fit protective devices every day, but these are special. Like £15 each special!  It is a BS 88 fuse, which in class, I call the Arnold Swarzenegger of fuses!  And why would I heap praise on this little beauty?

Well of course you can have a big bang on a job, whether caused by you or not!  On a domestic installation, the biggest fault current I have ever seen was 3,000 Amps.  Funnily enough this was on the mains featured in the latest instalment of the  ’Part P Doctor’…. Anyway , it is no big deal as you know that an mcb or fuse can easily cope with this potential fault current.  However, when you go into industry you will find that 3,000 is nothing much and can be far higher.  The BS88 fuse is AKA a HRC or HBC fuse.

These acronyms stand for ‘high rupturing capacity’ or ‘high breaking capacity’ and there is the whole story.  These types of fuse can safely break up to 80,000 Amps.  Yes you just read that right…… EIGHTY THOUSAND AMPS!

So, why £15 for a fuse.  Well that may have a little to do with the high quality silica sand filling of the fuse chamber or perhaps more to do with the fact that the fuse wire inside is silver…..  Cue “Ah ha Jim lad” ala Treasure Island!

So it is back to the drawing board for me then!

See you….

A got a call out from a local church this week.  He was a little concerned with the heating.  He had to switch it on and off by going in here!

It is a sea of botched wiring and plug in timers-truly scary…..!  Anyways, he asked could I fix it and of course I said yes, with a sly gulp!  He wanted the three zones controlling on individual time clocks so I wandered off to the wholesalers!  This is how the job went….

First task was to identify and mark all these pyros.  Next I chiseled through the rusty screws and dropped the panel.  This system had stuff that the church had never used, like vent fans so they asked for it to be all disconnected. All they want is their three heating zones…..

That is more like it!  Notice this box is smaller than the old one. The conduit is now a little short so that was the next job!

Now this is a tool you just have to have!  This is a self levelling lazer.  You can see I have put a dot on the side of the adaptable box ready for the drill.  Just got to set the new conduit by 25mm and cut to length…..

Now we hit rough waters!  All the pyros coming in the top are easy peasy, but this is where I need to be careful!  Because the new box is smaller, these boiler pyros from the bottom are short! What I did was to re-bend them to make them shorter still and gland them off to a metal adaptable box.  Remember, these are old cables with no earth tail, like you see these days.  The earth continuity must be good and it is achieved via the gland.  Tightened up here now, all is well!  It was then a simple job of joining the boxes with a small piece of tube containing  pvc wiring including a cpc connected to the metal box. Here is a closer look…..

Note the cpc fitted.   Also see how I set the different length cables to reach the same spot.  Yes, nice but it could turn ugly if the cable now fails it’s insulation resistance test!  Of course I am kidding- it all tested OK after the fettling!  Notice I have fittted a small peice of ‘din rail’ in the back and fitted what are called ’sax terminals’ .  Makes a real neat job I feel.  Anyway, nearly there now!!!

Now I did cheat here as the lid bit, I did in the garage the day before- a bit like ‘blue peter’- remember that- “Here is one I prepared earlier”  I made up the front, more din rail and sax terminations.  The rail also carries the three relays I need to make this work.  I have terminated all the cables I need and loomed up all the spare ones at the top….That is us all done now….

And so, there we are!  I have put an isolator on the unit for good measure and marked it all up…… Now a brief explanation of how it works.  Basically the power comes into the isolator and then out to the clocks.  Each output from each clock runs it’s respective pump.  As well as running its pump to also feeds the energising terminal of it’s own relay.  The three relays are wired in a parallel  fashion so when the pump supply pulls it in the relay switches on the supply to the boiler.  That way any clock will switch on its pump and boiler without affecting the other zones……. clever eh!

Till next time, all the best!

Alan

I am sorry for not posting for so long.  It has been a busy summer doing…….mmmm well not so sure.  That said, I have done an interesting install today and will write it up later.  For now though, the latest news is this:

I have applied for a full time post at my local college. Why am I doing this after all this time on the fringes?  Well, in July I took a job working for a large national contractor on a shopping centre outside the city.  Of course, it is normal to be treated as a child with the obligatory 2 hour H&S induction.  This one though had a twist!  In line with the modern site, you now have to wear big gloves to protect yourself.

During the induction the big boss invited questions-so far.  As a doctor of 30 years experience, I have never worn gloves full time so asked how I was supposed to connect up a ceiling rose.  The answer was quick and decisive, “Not my problem”

When I eventually got out on site, I started to dwell on this……… I went out into the street for a fag and thought about how it had all changed in my time.  Little Hitlers, who know nothing about ‘work’ have banned music, smoking etc- now I had gloves and goggles on to connect little wires!

I put the fag out, took off the hard hat, popped on my helmet and moonwalked to my beloved Goldwing- (oh by the way no parking for workers either). I surprised my long suffering wife as I walked in and announced my formal retirement from the construction industry!

So now I will only entertain little jobs where Hitler cannot afford to be employed…… Somehow, I am sure I will survive with no gloves and radio 2 in the background.

So to today.  This post at college has been advertised nationally so I could be up against formidable adversaries.  The applications closed at 5pm this afternoon, so win or lose I promise to let you know….

Bye for now!

Alan

I was back in Ireland last week on a family visit and just went round to look at my sisters mansion!  I will have to finish that first fix sometime- a good excuse for another visit me thinks!

Anyways a couple of pics for you peruse this week….. The first concerns the difference in Irish regulations to ours.  Check out my mothers consumer unit…….

Not very clear, this, but first the story.  Ireland gained full independence from the UK around 1937.  The UK nationalised our supplies around a decade later.  The Irish government  went to the Germans for help so the Irish adopted German regulations and this is the result. On the left is a SINGLE POLE MAIN SWITCH.  Next along is a ‘diazed’ MAIN FUSE of 63A rating.  After this is then regular breakers of which there are four.  Next is an ELCB (Earth leakage circuit breaker) which we call an RCD. After this there are three RCD protected breakers supplying sockets.  Finally there is an RCBO at the right end that I fitted donkey’s years ago to supply a shower for dear mother.

The supply is what we call a PME (protective multiple earth) or more recently a TN-C-S.  The Irish have a real cool name for this…… Get ready…… ‘neutralised’!

The second of this weeks pictures was took in the street outside the pub!  So you see, even when in party mode, I still put my readers first, all seven of you!  (that is a joke!)

This explains why, across Europe the regulations people adopted the 230/400V standard.  It is mid way between us on 240/415 and our European neighbours who are all on 220/380V.  With our tolerances we can all be good 230/400V Europeans!!!

During this Easter period, I have been sitting around and catching up with my Cert-Ed, which is a qualification that I must have to practice as a teacher.  It is not interesting really but it has to be done, as they say!

After the initial success of the Part P Doctor Second Fix, I have dusted off the lap top and am busy again!  I have decided that people need a no non-sense guide to the 17th Edition of the regulations book.  All these years as a student and teacher reading ‘the opposition’ has made me ill!   Anyhow, I have been on it now a few days and have put lots of stuff down.  I will be off to see the intrepid Dave Gee tomorrow to start doing his magic with artwork for it.

Game on!

Last week I dusted off the tools and went back over to my local Royal British Legion.  They are fed up with soaring electricity costs so asked me to put the toilet lighting on motion detectors.  It was nice little job so I took a few photos for you.

The first thing is SAFETY FIRST! Just because it isn’t school or you’ve been doing this for years you must follow your safe isolation procedure. I have pulled the fuse for the lights and checked for ‘dead’ there.  I am now back at the mains checking the lamp.  By the way I am in the building alone so not locking off the whole mains is not required, I am perfectly safe.

Next job is to connect in the sensors.  Now this pretty easy as the club is wired with ‘Greg’ type ceiling roses.  ”What?”, you say.  This is what I mean….

All the fittings are on socket outlets that fit on conduit boxes.  There is a spare ‘loop’ terminal in these so I don’t even need a connector.  Here is one of the detectors……

When I finished each part I then tested.  One of them didn’t go so well when I came to it, but more about that in another posting!

Bye for now.

This week’s chit chat is about education.  As we know the economy is in tatters so cuts have to be made.  The Government have decide to scrap the NVQ system changing it to a new system called QCF.  ”So what?” I can hear you say.  Well Government funding is to be withdrawn unless you are in the trade on an apprentiship.  This means my days are probably numbered in my local FE college.  I work through an agency so I feel I am walking on thin ice!  As a writer and teacher I am not match fit but will be OK once I get back in the groove.  So has anyone anything they need bodging fixing up

I was teaching this week and the fire alarm guy was round servicing the big panel in the entrance hall.  The panel sits there with no wiring showing, so it must be wired from “round the back” so to speakso of course curiosity got the better of me and I wandered around the reverse of the wall….

nice job, yes?  The original installer has glanded off everything into an adaptable box so the tails can pass straight through the wall to the other side.  The bottom left one is a real fat one so must be a multicore cable, perhaps a seven core.

I have pulled down the shroud to the right of it to let you see closer. This is real class cable and not mush installed these days. In class, I only have one bit of advice, look out for “Billy the burr”

This is a not too clear picture but that does not matter.  Billy lurks deep inside the pot and is a little wisp of copper that peels off and bridges the cores when screwing the pot on.  Watch out for him, he is bad news!

Till next time, see ya!