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Discuss What is the best way to wire this bench testing setup? in the Electrical Wiring, Theories and Regulations area at ElectrciansForums.co.uk.

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  1. midiman
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    midiman Active EF Member

    Hi,

    When we were in College we setup up a lab using a Bench PSU, a Mini Consumer Unit and some lights etc...

    It wasn't the best setup but it gave us an idea into the principles of wiring up circuits etc...

    From the picture here you can see that the leads they gave us were not the best but it worked.

    psu.jpg

    I've got the same PSU in my lab and I want to re-create the setup again, albeit properly.

    The lead in the pic was just a bit of twin an earth that went to a connector block wired to the consumer unit.

    consumer.jpg

    Is there a better way of doing it?

    Thanks
     
  2. Pete999
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    Pete999 Trusted Advisor

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    Northampton
    In my last job, I had built several test boards, which consisted of
    A small consumers unit, wired from that CU a small RFC, a 13A radial, a lighting circuit and a DOL SPN contacter, fed from a 13Amp socket which was non RCD protected, students could carry out all the test required apart from Earth rod testing, and of course the Ze was the Zs of the socket used to feed the board, not ideal but it worked for us, is this the sort of thing you were asking about?
     
  3. midiman
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    midiman Active EF Member

    Hi, yes.

    I want to setup a test board using the same power supply that you see in the picture.

    All I want to be able to do is create a lab where I can test some socket and lighting radials etc...

    I just need to know what of leads I should use to use to get from the PSU to the Consumer unit, and what type of Consumer unit should I get.

    The one we used looks like a mini Garage Unit with 2 MCBs. I took pictures at the time but I didn't get all the specs of the setup.

    It wasn't a great setup but I would like to re-create again, but safely.

    Thanks
     
  4. Pete999
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    Pete999 Trusted Advisor

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    Northampton
    May I ask why you need a PSU?
     
  5. midiman
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    midiman Active EF Member

    Because that's how we were trained to do it in the workshop.

    What is the other method, I don't really want to be tapping into or running anything off the house supply.
     
  6. spinlondon
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    spinlondon Trusted Advisor

    Location:
    Harlow Essex
    May I ask why you need to feed a CU from the PSU?
    Seems to be you should already have a CU somewhere. To then plug in a PSU to feed another, seems a bit over the top.
     
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  7. Pete999
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    Pete999 Trusted Advisor

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    Use an extension lead, as I said it wasn't an ideal set up, but using a PSU seems a wasteful resource, you would need to feed the PSU anyway so why bother?
     
    • Agree Agree x 1
  8. midiman
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    midiman Active EF Member

    In the college labs.

    We plugged the PSU into the 3pin outlets on top of the desks, then ran two leads from the PSU into a mini consumer unit.

    That was the setup and then we built the radials on the board fed from the consumer unit etc...

    This was the board setup
    setup.jpg

    Thanks
     
  9. Resu
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    Resu Trusted Advisor

    Location:
    Scottish Highlands
    Google "banana plugs" and you should find some that you could easily wire a bit of flex onto.

    The board could be anything you like, as you said, a small garage consumer unit would be ideal. Make sure you get one with enough ways to cover the amount of circuits you intend on wiring up.

    If you post up your location someone local might have an old unit in the back of their shed they may be willing to give you.
     
  10. midiman
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    midiman Active EF Member

    Ok so you are suggesting just running wiring up a bit of twin an earth to a 13A plug and doing it that way instead of using the PSU?

    I can see what you are saying but I'm just trying to work out why they made us use the PSU then.

    The PSU has variable voltage control, overload protection and a fan etc..
    The extra consumer unit in the setup was there to get us to learn about wiring up a CU.

    Like you say they may not be needed to a pro but it helped us to get an idea of what we need to do.

    Thanks
     
  11. Resu
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    Resu Trusted Advisor

    Location:
    Scottish Highlands
    I can only imagine the PSU was used as a safety factor but that would be a guess.

    If you were to go down the wiring into the mains method, you should use a length of flex (1.0mm or 1.5mm 3 core) with plugtop on one end and a stuffing gland into your board at the other.
     
    • Agree Agree x 2
  12. midiman
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    midiman Active EF Member

    Thanks

    I only want to wire up to a maximum of two circuits so I don't need anything major.

    I just want to add some sockets, lights and switches.

    That would be nice because the cheapest Garage Consumer Units are around £35 and the PSU just cost me £20. Although I got that at a decent price because most places want £120!!

    I just need an old Garage CU.
     
  13. Dannyg8810
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    Dannyg8810 Electrician's Arms

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    Leeds
    Resu’s suggestion sounds like all you need to do
     
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  14. Resu
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    Resu Trusted Advisor

    Location:
    Scottish Highlands
    Shop around a bit, as it's for a test rig it doesn't have to be anything fancy.

    Here's a brand new one for £20. Link.
     
  15. Pete999
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    Pete999 Trusted Advisor

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    I would volunteer if the OP isn't to far away
     
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  16. midiman
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    midiman Active EF Member

    Hi thanks that looks about what I need.

    I have just seen this one on Screwfix site if I wanted to get it today.

    British General 5-Module 3-Way Populated Garage Consumer Unit - https://www.screwfix.com/p/british-general-5-module-3-way-populated-garage-consumer-unit/1926g#_=p

    Thanks Pete999.

    I appreciate the help but I am in Berkshire just outside London.

    I will buy one if I have to.

    Just wish I didn't buy that PSU now lol. At least I didn't pay £120 for it!!
     
  17. Resu
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    Resu Trusted Advisor

    Location:
    Scottish Highlands
    Hey there's no reason why you can't use it really, you could use it until you're confident enough to use the mains. I'm sure you could sell it for what you bought it for too.
     
  18. midiman
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    midiman Active EF Member

    True and I may even be able to sell it for more than what I paid. It's a really nice unit compared to all the others that I have seen.

    So all I need are some banana plugs and 1.5mm flex for the PSU method.
    13A Plug, 1.5mm flex and stuffing gland for the mains method.

    Banana Plugs and 1.5mm flex for the PSU method.

    And a Garage CU est £20-£30.

    I have to go to Screwfix today so I could get everything today. Or order from Ebay if I want to save a bit of money.
     
  19. Pete999
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    Pete999 Trusted Advisor

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    deleted
     
  20. Resu
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    Resu Trusted Advisor

    Location:
    Scottish Highlands
    You'd be as well ordering online for the CU, but see what they have in your local Screwfix. Plugs are only a quid or two. Banana plugs could be picked up in the likes of Maplins if you have one nearby. The flex would probably be best bought online as you only need a few metres. Alternatively you could sacrifice a few metres off the end of an old extension lead if you have one!
     
  21. spinlondon
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    spinlondon Trusted Advisor

    Location:
    Harlow Essex
    I imagine the PSU was used at college, partly because they had one knocking around, partly because they didn’t want Students’ mistakes knocking out half the college and partly to provide a separated safe supply for the Students to work with.
     
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  22. midiman
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    midiman Active EF Member

    Hi Spin,

    It was probably due to safety.

    I just wanted to make sure that I was not doing something overly wrong because they never really explained it to us.

    We were just told to use them and they units are marketed for use as School Lab units.

    Thanks
     
  23. midiman
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    midiman Active EF Member

    Hi Resu,

    I've just had a look around and Screfix have a CU for £29.99 at my local branch.

    I need to go there today to take some items back for a refund. But my refund would get swallowed by the extra cost of the CU from them compared to the one that you showed me.

    So I might just order some of this stuff off Ebay because I an not in a major rush for it.

    It would be nice to get it all today but I can save myself £10-£15 by waiting a couple more.
     
  24. ipf
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    ipf Trusted Advisor

    Down to safety? The main points to look at regarding safety are the scattered open live connections.....
     
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  25. Pete999
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    Pete999 Trusted Advisor

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    Location:
    Northampton
    Yes I noted that as well ipf
     
  26. spinlondon
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    spinlondon Trusted Advisor

    Location:
    Harlow Essex
    Remember the PSU provides a separated supply.
    Whilst the CPCs are connected at the accessories and the small CU, there is no Earth between the PSU and the small CU (or at least there shouldn’t be).
    Whether the set up shown complies with BS7671 is debatable.
     
  27. midiman
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    midiman Active EF Member

    Hi guys.

    What cabling should I use for the circuits?
    1mm TE for the lighting?
    1mm 3Core for switch to switch

    1.5mm TE for the electric sockets?

    Thanks
     
  28. HandySparks
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    HandySparks Trusted Advisor

    Location:
    Hampshire
    Business Name:
    Neish Electrical Services
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