Chassis "earth" and welding "earth"

  1. bumbler New Member

    Messages:
    7
    Location:
    Southampton UK
    Hope this is the right place to ask - maybe someone will put me right if not.
    I have a Clarke 151TE which has chassis earth connected to the 240v supply earth as one might expect. The welding "earth" cable is not connected to chassis earth which appears to be a deliberate design point.
    I want to provide a meatier welding earth connection with a sensible Dinse connector on the front panel. I guess I should use an insulated Dinse socket to respect this arrangement - BUT most seem to be a simple clamp (back threaded conducting element is also the fixing). A larger insulated item would clearly require a much bigger hole in the front panel and guiess what, it's right in the corner.
    So what is current :-( thinking about allowing welding "earth" to be connected to the chassis via the front panel ?
     
  2. Munkul Member

    Messages:
    555
    Cumbria, UK
    No.

    A welder is designed to allow a specific current/voltage to follow from the electrode, through the arc and workpiece, and back through the return lead ("earth" is a misnomer, it's simply a return path, can be either +/- polarity depending on welding process).

    The EARTH inside the chassis is to provide a safe return path to actual "earth" through internal wiring, in the occurance of a short circuit within the machine, which then will trip either an RCD or a fuse/breaker. I.e. to stop YOU being part of the return circuit.

    Your return lead is perfectly adequate for your machine's 150 amps, the best upgrade is usually a better quality clamp with plenty copper for the connections to workpiece.

    A dinse socket is always isolated from the chassis of a machine, even if you can't see it in pictures.
     
    BarrieJ and eSCHEn like this.
  3. bumbler New Member

    Messages:
    7
    Location:
    Southampton UK
    Thanks. The reason for the Dinse socket is that I have a substantial lead with a good clamp on another machine which then becomes interchangeable. The return lead on the Clarke is actually rather skinny whilst the "clamp" is more like a paper clip.
     
  4. Cobbler

    Cobbler Codger bodger

    Messages:
    4,263
    Location:
    Gloucestershire UK
    I & several others have fitted a Dinze socket to the front panel to fit a longer return lead. The Dinze sockets have insulated washers to isolate it from the front panel, on mine the panel was already cut to fit one. If you look back through the Clarke section you will find a write up.

    Edit ..... found the post
    https://www.mig-welding.co.uk/forum/threads/small-160tm-mod.61208/
     
  5. colnerov

    colnerov Member

    Messages:
    3,117
    Location:
    Nr Gatwick UK
    Hi, The lead will be adequate for the machines capacity but there's nothing stopping you putting a better clamp on if that's what you want.

    Colin
     
  6. bricol Member

    Messages:
    673
    N.Yorks, UK
    If you connect machine earth to welding earth, it's still work . . . but when you get a bad welding earth connection to the component being welded, if its on a metal bebch, the welding current will "earth" through the nearest connection in the earth circuit of a metal power tool on the bench . . .

    Don't ask how I know . . . took two melted power cords, one on a my pillar drill and then the welder for me to work out there was a problem in the welder . . . kept wondering what the hot plastic smell was . . .

    RCD didn't trip . . .
     
  7. jimbo84 Member

    Messages:
    452
    Location:
    Up North
    I did this to my mig so that I could use my longer and heavier duty arc welding earth return lead, trailing dinse socket isolated from the welder body. It very nearly wasn’t isolated but a member on here put me right.

    F2372036-B60B-4492-8CA1-D638735A74EC.jpeg
     
  8. bumbler New Member

    Messages:
    7
    Location:
    Southampton UK
    Thanks to everybody for many useful reflections.
     
  9. BarrieJ Member

    Messages:
    545
    Location:
    Milton Keynes, Bucks, United Kingdom
    Since I've retired I don't weld so much now but with arthritis in both hands I was finding using the crocodile style return clamp difficult to manipulate one handed.
    I came across this type on eBay £8.50 delivered, (mine arrived fully plated and in better condition than this one) solid brass, quite well manufactured considering its price and doubtless country of origin.
    Really easy to wire, manipulate and good for 600 amps, about 3 times what I'm likely to be needing these days.

    s-l640.jpg
     
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