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V.O.E.L.C.B.

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It dawned on me fully today while working in an old holiday chalet circa 1940s.


The man in the next chalet was trying to use his old Black and Decker 1970s car boot sourced electric drill outside on the grass. He was making a wooden clothes hanger with wood and pegs. A jolly good job too.


I had had a quick look inside his chalet as he needs some new sockets. The  fuse box is an old cream coloured Wylex 6 way unit with fuse wire carriers. There is an old Crabtree V.O.E.L.C.B. installed before the fuse box.


As he worked in the garden drilling wood, it dawned on me that he had zero shock protection as he would if he had a R.C.C.B. installed.


It's strange how a picture speaks a thousand words.


Z.


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    (there was worry about damage from e.g. nearby lightning, though one comment mentions no recorded trouble). 


    The excellent quality Crabtree E-60 model V.O.E.L.C.B. has a lighting protection spark gap (discharge gap) installed internally in parallel with the trip coil.


    In the mid to late 70s, a Crabtree 100 Amp E-60 model, without overload protection,  cost approximately £8.40 plus VAT. VAT tax was half the rate it is today at 12.5 per cent.


    Z.


     


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    Sparkingchip:
    T C Gilbert


    Thanks Sparkingchip. The article is most interesting and ahead of its time.


    Z.


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    I read the T C Gilbert article can't say I completley understood it  I don't think the idea of earthing a small farm motor with a stake just like he describes is allowed now is it?
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    Have a look at Table 5 on page 12 in This article listing the causes of broken neutrals in the distribution network ?
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    Zoomup:

    The excellent quality Crabtree E-60 model V.O.E.L.C.B. has a lighting protection spark gap (discharge gap) installed internally in parallel with the trip coil.


    In the mid to late 70s, a Crabtree 100 Amp E-60 model, without overload protection,  cost approximately £8.40 plus VAT. VAT tax was half the rate it is today at 12.5 per cent.




    Thanks - actually not quite so expensive as I'd have guessed.  Using BofE's inflation calculator on £8.40, and adding today's 20% VAT, it's around £75 total.  (Historical vat appears more varied than I remember - not quite 12.5% in the late 1970s.)  Some modern RCDs from the fancier names could be that much, even without special features of what waveforms they handle. 


    I didn't remember the spark-gap, but I remember contacts for disconnecting the installation (F) terminal while pushing the test button.

     


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    Sparkingchip:

    Have a look at Table 5 on page 12 in This article listing the causes of broken neutrals in the distribution network ?


     


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    I read the T C Gilbert article can't say I completley understood it I don't think the idea of earthing a small farm motor with a stake just like he describes is allowed now is it?

    I guess it's rather like having a local TT island - as long as there are no other exposed-conductive-parts or extraneous-conductive-parts within reach, and (the equivalent of) an upstream RCD - it would just about pass today.


     
    Historical vat appears more varied than I remember - not quite 12.5% in the late 1970s.

    I recall 8% for 'essential' items and 12.5% for 'luxury' items. The categorization did seem rather arbitrary at time though.


       - Andy.
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    It seems that no one is going to pick up on a major cause of lost neutrals were bombs, balloons (which I presume were barrage balloons) and aircraft.


    Even back then, during the war there was a major concern about lost  neutrals and PEN conductors in PME distribution networks and attempts were being made to install neutral and PEN fault detection devices to disconnect the supplies.


    It looks like we are seventy years behind T C Gilbert and his peers.
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    I didn't realise PME  had been around that long I 5hought it was invented in the 1970s
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    Perhaps we have gone full circle.


    Back in the 1940’s the distribution network was considered unreliable due to war damage, then through the fifties and sixties everything got tidied up after the nationalisation of the individual electricity companies by the Government, but after seventy years and denationalisation we are back where we started due to a lack of maintenance and upgrades.

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