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house wiring wrong colour codes nearly got me

Discussion in 'Hobby Electronics' started by matt2-amstereo, Jan 8, 2006.

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  1. I live in a house built about 20years ago, Yesterday i decided that the
    BC light fitting had to be changed in the kitchen The existing light
    output is dismal even with a daylight CF.

    So i changed it for a 4' fluro. the wiring in this house uses a
    standalone earth cable (2core red/black for power and single lead beside
    it for ground) so i unscrewed the BC holder, screwed the 4' up and wired
    it up with red (which had 2 leads) to brown, black to blue and
    standalone black to ground, all was good, re-set the breaker and the
    light came on even tho the switch was OFF. thought this was strange, so
    pulled the tube out to shut light off over night, come this morning, i
    sought out to investigate what was going on.. I removed the switch from
    the wall, this is where i discovered, THEY USED BLACK AS THE ACTIVE
    SWITCHED.... this is a single switch fitting.

    what i had was active switched to the shell of the fitting, neutral to
    its spot and the red pair on active.

    Im surprised that the shell didnt arc out or do anything nasty, and that
    the house used BLACK as an active,... good thing we have fast acting
    breakers, thats all i can say.....

    Is it normal for black to be used with active power?
  2. the other thing that amazes me is the fact that a 4' can work without an
    earth, some were i read that balasted fittings needed an earth to
    actually work in the first place.... guess they may have been wrong
  3. Poxy

    Poxy Guest

    I thought the convention was that power is run to the fitting, the neutral
    and earth connected and the active run to the switch and back. If the power
    is at the switch perhaps it wasn't a professional installation?
  4. Dand

    Dand Guest

    I don't really follow what happened. Is your entire house black on the
    active? Or did they just use some black cable for a single switch?
  5. no, just this switch, its back to back with another light switch on the
    other side that switches active through a red feeder to the fitting. i
    had a look at it, cause i assumed the switch had gone dodgy, as if the
    contacts had stuck closed, but imediatly i saw that the only thing dodgy
    was the use of a black feeder to this one light fixture.

    the usual convention is to have the active/neut cable feed to the lamp
    with the switch in line with the active. the oposite switch is done
    right, this one calls for the unswitched active to join on a spare (un
    used)screw connection in the lamp fixture which is available in BC lamp
    fittings but unavailable in fluro housing, which only have provision on
    the terminal block for active neutral and earth, therefor this extra
    unswitched feed needs to enter the fluro fitting (being in the same
    jacket that the neutral lives in) and be capped off so that a)it doesnt
    touch anything and b) so feed can continue to the remainder of
    lamps/switches on this circuit, Is this normal?
  6. turns out this type of wiring setup (using the black leading from switch
    to lamp is common in the UK and the circuit is deemed a 'ring' , ive
    seem flats and houses at the pre-skin stage and looking at that wiring,
    they seem to use the more power-switch-lamp method instead of the
    power-lamp-switch-lamp this place seems set up with...

    must be an old technique from our british roots or somthing
  7. **You're an idiot and you live in QLD, right?

    There's a reason why those people who don't know what they're doing use
    properly qualified people. Then there's the dead ones. They're the idiots.
    Sadly, in QLD, the standards for electricians is (or was) so low, that many
    problems occurred.
  8. Tom

    Tom Guest

    For a few dollars you can buy a neon screwdriver/tester and work out the
    wires... if you going to rely on colours and reliable electricians
    you'll die one day.

  9. Ken Taylor

    Ken Taylor Guest

    A proper sparky would have been wise to that. It was quite okay until
    pretty recently to use any (repeat - any) of the cores for active. More
    recently the active had to be sleeved if it wasn't the red or brown,
    then more recently again the earth couldn't be used at all for power.
    Here in NZ anyway, and I'm betting it's just a few years/decades behind Aus.

  10. **Don't sweat it. Just evolution in action. Morons doing their own
    electrical work need to be weeded out of our gene pool.
  11. That is what I mostly find, but 50% also use twin core with red as
    active to the switch and black as the switched active back to the light
    fitting. Shudder.
  12. Poxy

    Poxy Guest

    That's actually what I meant - the run to the switch and back is twin-core,
    often red and white - isn't this how it's meant to be done? Is there some
    convention as to which wire is meant to carry the active to the switch?
  13. Gee, thats a bit harsh. This is actually quite common, and not just
    here in QLD.

    My guess is that it was wired the traditional way, then a second light
    fixure was wired into the switch at a later date.
  14. From memory, a light fixture needs no earth. Is a flouro batten any
    different? There may be something to do with the hight of the fixture
    too. I did once know all the SAA rules, but they are long gone. I
    remember throwing away the book about 3 or 4 houses ago!
  15. **Harsh? Get real. Only a complete idiot would wire up anything, without
    checking the wiring first.

    This is actually quite common, and not just
    **It has been traditionally more common in QLD, due to lower standards.
    **Perhaps. He is still a moron. If he had no clue about what he was doing,
    he should employ someone who does. If the gearbox in my car goes belly up, I
    would not pull it out and then complain because I could not get it back
    together again. I would employ a professional to do the job.
  16. its all good, i worked out what the problem was, just didn't expect that
    they'd use black to carry active....

    as far as using or not using earth, certain types of fluro fittings
    wouldn't correctly fire each time, but i dont believe that has anything
    to do with pre-heat type ballasted fittings.

    this is an ex RAFF house, maybe theres the explaination?
  17. atec

    atec Guest

    Its an old hangover from post war sparkys , many could do the work so
    were considered ok yet were not in effect tradesman , many used a
    common earth rail down the roof space and looped the active in a twin
    across the active then switch then fitting to make the circuit and the
    neutral really was added when required to make suitable , was helping
    a mate recently in an old house in Brisbane and most of it was a rewire
    but some was very old ( about 40 years) with everything bundled and
    taped in a group star fashion in the roof all actives via the first
    light switch , (a real head shaker :)
  18. John G

    John G Guest

    I think you will find an EARTH must be carried to every light fitting
    whether or not it is metallic so that it is there if there is a change
    Someone who needs to know Australian Regs could confirm.
    I am just an old radar tech who tries to stay aware of these things for
    my own good.

    Some flouros were temperamental if the frame was not earthed but that
    was to do with striking the "arc" inside.
  19. thats what confused me, everything i've ever learned previously was
    wrong in this case. I have learned somthing tho, check the light switch
  20. thats what got me, cause i knew there SHOULD be one, and the single
    black lead (not paired) resembled the other earth leads here.

    the fitting is fitted with a solid state starter (blue units) that start
    a tube in 2 seconds, it replaced a stock BC fitting that had a daylight
    CF installed, the light quality is SO much better, well worth the
    learning experience, which is, don't trust anyone else's work
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