old welder wire colours

  1. zardoz

    zardoz Old school Socialist

    Messages:
    2,219
    Location:
    Chetser, UK
    I have just taken out an old machine i bought a while back. I don't know how old it is, probably just 1980s, but it is definitely 240v single phase, however i dont recognize the wiring in it. The earth is easily seen but the other two wires are black and green. Which is neutral and which is live ?

    The 16 amp blue plug was not on it yet. I have just put it in to give an idea of the colour balance of the picture. IMG_0675.JPG


    [​IMG]
     
  2. Got me stumped, the old 3 phase colours were red, yellow, blue. Neutral was black and the CPC as always is green yellow.
    Could be what you call green is actually blue and the black is the neutral.
    Best bet is to whip the cover off and see which colour is fused or switched.

    Is this an oil cooled welder? In which case it won't matter which way round the live conductors are wired. The reason I ask is that my Pickhill Bantam, which will run on single or 3 phase, had similar colours but one conductor had been cut off and the insulation stretched back over the end.
     
  3. Just to add to the confusion this is on Wiki

    There is a long history of colour changes, older systems (until the 1960s)in the UK often had white instead of yellow as second phase, and before WW2, a black earth and a green third phase in place of green earth and blue phase was permitted. The regulations actually permitted (and still do) the use of any wire colour that is not an earth colour, providing it is unambiguously identified at all connections by clear labelling or by correctly coloured over-sleeving. This clause allows old systems to be kept operational safely and compliant with minimum additional effort.[citation needed]Direct current mains supplies are now only of historical interest in the UK but the colour-coding was red for live and black for earthed (regardless of the actual polarity). Hardly any loads were polarity sensitive at this time (principally incandescent lighting; heating systems or series D.C. motors). It was considered more important to identify the live wire than the polarity. Where all three wires were available, the historical colour code was red (positive), black (middle) and white (negative). The negative line changed to yellow in 1964, and then to blue in 1966.
     
    Last edited: May 27, 2015
  4. rtbcomp

    rtbcomp Moderator Staff Member

    Messages:
    18,615
    Location:
    Sheffield UK
    On American Equipment Black was live, white neutral and green earth.

    Check with a multimeter, the earth will have zero ohms to the machine case (NOT the welding "earth" or return).

    Then have a look inside. If it has a single pole mains switch the wire connected to that will be live,

    If it has a mains fuse that should be in the live.

    Personally I'd replace the cable with a blue/brown/ green-yellow one.
     
    eSCHEn likes this.
  5. zx9

    zx9 Member

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    4,046
    Location:
    South East London
    That was my first thought, then you will know it is correct next time you need to change the plug or shorten the cable.
     
    eSCHEn likes this.
  6. Appyasme Overhead twin cam 3 phase and neutral

    Messages:
    617
    Location:
    Lancashire
    Red to red, black to black,:flame: and blue to bits
     
  7. Appyasme Overhead twin cam 3 phase and neutral

    Messages:
    617
    Location:
    Lancashire
    Joking apart it looks like you have earth and the neutral has a blue sleeve on it which makes the other lead the live.Easy peasy
     
  8. brightspark

    brightspark Member

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    30,415
    Location:
    yarm stockton on tees
    black line , blue neutral and green yellow earth people are going to have to get used to the fact that black is now a live and blue is neutral :)
     
  9. Appyasme Overhead twin cam 3 phase and neutral

    Messages:
    617
    Location:
    Lancashire
    I agree,I think the age of the machine could indicate whether the colours are the new type or old type,I would say that they are the old type.But,point taken
     
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