Irwin Power Supply Powerbase 32 Frayed Cable

Discussion in 'Supporting Physics' started by Lesley Newcombe, Nov 5, 2019.

  1. Hi folks - I have just had 5 Irwin Powerbase 32 units fail their PAT test as the mains cable has frayed where it enters the body of the power pack. Has any-one repaired the mains cable themselves? I'm not sure it is some-thing I should be tackling myself? The teacher seems to think it will be a simple fix but I am not sure sure having had a look inside. Thanks
     

    Attached Files:

  2. If the connections on the inside are solid i don't see why it couldn't just be taped up.

    That said it doesn't look frayed as such it looks like its just been pulled out of the housing slightly
     
    Lesley Newcombe likes this.
  3. Hi Biobee - it's definitely frayed, it continues as intact cable on the inside for a length of around 3 inches. Not sure taping would work as it is too close to the body of the pack
     
  4. Nick Mitchener

    Nick Mitchener COMMITTEE

    Taping is not acceptable. We have used heatshrink where there has been some reduction in insulation but this fault here is an easy fix. You can buy a special tool on ebay for this type of cable gland but I squash them in a vice to remove and replace them. You can usually just push more cable through into the unit and then reseat the gland, but if the insulation on the wires themselves is damaged you need to shorten the cable and start again. The cables are plenty long enough.

    These things are a bit awkward but in common use so a skill worth developing. We have them on most of our microscopes.
     
    Lesley Newcombe likes this.
  5. Hi Nick - yes, I wasn't thinking of taping it. My main problem is getting the cable out of the fixing (is that what you mean by the gland?) It's in so tight, as it should be. I might have to invest in a tool. The physics teacher seems to think the re-connection can be done using a Wago clip? Anyway, I am checking with the school Health and Safety Officer before I do anything as I have no qualifications and I may not be covered by the school's insurance. Appreciate the advice - ps just google gland so I know what it is now :)
     
    Last edited: Nov 5, 2019
  6. Nick Mitchener

    Nick Mitchener COMMITTEE

    If you look closely at the gland you will see that there is a rectangular piece that is part of that shape you see. You have to compress that bit down on the cable to make the thing fit through the hole in the panel. That's why I use a vice, just line up that bit with the jaws so that you compress it into the cable, a bit of a wiggle and it will come out. Move it along the cable, compress again and refit. It is easier if there are two of you but you can do it alone.

    I have used swan necks but I find the vice is the easiest way if you don't have the special tool. The special tool is about a £15
     
    Lesley Newcombe likes this.
  7. Hi Nick, thanks - I'll have to try the vice down in DT. I can make the thing spin using pliers but just can't get enough grip to pull it out.
     
  8. Nick Mitchener

    Nick Mitchener COMMITTEE

    Spinning it is a bad idea as you might break conductors. Once you have it lined up in the vice and very well gripped you can get it in and out with a sort of rocking motion. When you have it out have a close look at it and you will understand more how it works. They are a pain but they are very strong at gripping the cable. It does weaken the outer sheath though and does eventually cause that split, however in 7 years of repairing them I think I have only ever had to rewire one item. (plus one other where we changed a transformer but that wasn't the gland's fault)
     
    Lesley Newcombe likes this.
  9. Thanks again - I am able to spin it as I have cut the cable on the opposite side :) I am wondering if it is ok to use an in-line junction to connect the two bits of mains cable rather than having to redo all the connectors? Or is that just nor safe enough? As you can guess, I am probably not the right person to be tackling this. Have left the cable with the DT teacher who will try and get it out for me
     
  10. Nick Mitchener

    Nick Mitchener COMMITTEE

    I would not add an extra fitting. These things have a hard life and should be returned to the original spec otherwise you have to take responsibility for the design change.

    As long as the D&T guy looks closely at it to get it in the vice the right way it should all go fine.
     
  11. Thanks for confirming that, makes sense. Appreciate your help
     
  12. I don't think it's safe to use an in-line connector for this environment, especially as it's for portable equipment.
     
    Lesley Newcombe likes this.
  13. Sounds a bit painful putting your gland in the vice !! :eek::eek:
     
    KeithD and Lesley Newcombe like this.
  14.  
  15. Dod

    Dod

    If the entry gland is rounded with flat sides (best description) then a good tool is waterpump pliers, just squeeze the gland and wiggle (the gland - not you) and the normally come out.

    If the inner wires are undamaged then put gland back on to a fresh part, if damaged strip and reconnect.

    And as all good manuals say -- fitting is the reversal of removing.
     
    Lesley Newcombe likes this.
  16. Thanks - I've taken pictures to keep track of what goes where. Cable is damaged so it needs a re-wire. Need spade connectors and a crimping tool now! Hoping we have them at home.
     
  17. Nick Mitchener

    Nick Mitchener COMMITTEE

  18. Nick Mitchener

    Nick Mitchener COMMITTEE

    you can probably reuse the spade connectors. you can open up the crimps and solder usually.
     
  19. That's great, I know where to get some more if it breaks too. I did wonder about re-using the existing connectors - many thanks again
     
  20. you can crimping with regular pliers, just don't cut through.
     
    Lesley Newcombe likes this.