Install Power Sockets In Workshop - Good Practice

Discussion in 'Electricians' Talk' started by SomeOfTheGear, Oct 1, 2021.

  1. SomeOfTheGear

    SomeOfTheGear New Member

    I've got a Workshop that already has power to it installed by the previous owner (a builder). It's fed by a separate 63Amp fuse in its own distribution box off the main supply board in the House. The cable goes outside into the garage into another small distribution box where there's another 63amp fuse. This box has 2 fused circuits, a lighting circuit and a power circuit. Both are in a radial configuration. There's also a spare slot for another fused circuit.

    Main Fuse Box in House
    Main Fusebox.jpg

    Workshop Fuse box
    Workshop Fuse Box.jpg

    The Power circuit already has a couple of plastic sockets installed that I'm going to replace with metal ones. Most of the wiring is in the roof area of the Workshop with runs vertically down to the sockets and either bare or covered in plastic trunking.

    I'm going to be using a few Power tools, (Table Saw, Thicknesser / Planer, Mitre Saw) but only ever one of these plus dust extraction at the same time!

    QUESTIONS
    1) Based on the above, is there anything I need to change to make comply with regs or good practice?

    2) The unprotected heavy duty cable to the Workshop exits the house through an airbrick and disappears underground to reappear out of the gravel into the Workshop. I'm guessing this should be an armoured cable buried to a given depth with warning tape? Happy sorting this out with proper cable but what's the recommended method of joining the cables where it exits the house / enters the workshop? A weather proof connection box of some sort?

    3) What's the proper method of organising the power circuit/s in the Workshop? Just extend the existing radial? Add a second radial in the spare fuse slot? I think the ideal configuration is a ring circuit (?), if so, can this be done with the existing supply?

    Not wanting to be obsessive about this BUT I need to be sure it's done properly as no one wants a tickle from Mr Sparky!

    Thanks.
     
  2. Coloumb

    Coloumb Screwfix Select

    It's not a 63a mcb it's a 50a mcb with a 30ma rcd. As the garage CU also has a 30ma rcd you have two 30ma rcd's in series which is a bit pointless. Really horrible to see the missing blanking plate on the CU, hope you don't have children about. That's just about the most dangerous situation I've seen on the forums ever. Really you would need to check the type and cable size used on the sub-main as a 50a breaker is pretty enormous for a shed supply so chances are cable size is probably under sized.

    Soz about the edits didn't read your post properly.
     
    Last edited: Oct 1, 2021
  3. SomeOfTheGear

    SomeOfTheGear New Member

    No kids, it's 8ft up in a locked Workshop. However point taken and blanking plate will be on next screwfix order.

    It seems to be circa 12mm wide cable, deffo not shower / cooker cable but looks thicker than standard ring main cable.Would you suggest a lower capacity RCD in one of the CUs? Tx for the reply.
     
  4. Coloumb

    Coloumb Screwfix Select

    SF don't sell chint blanking plates. Sounds like it's some sort of twin and earth but you really need to know the exact csa. sometimes if you know what your looking for it's printed or embossed on the cable. In any case it should really be replaced with swa if any of it runs outside. I wouldn't mess around with the rcd's as it's likely the 1st one is protecting the submain IF it's twin and earth. SWA doesn't need rcd protection.
     
  5. The Happy Builder

    The Happy Builder Screwfix Select

    There’s a very good chance that trying to run the equipment you intend to use will trip the B16 MCB due to their starting current.

    You need an electrician to give it all the once over and tweak it.
     
    spannerw likes this.
  6. Bazza

    Bazza Screwfix Select

    Ooh Chint! I can smell the quality from here. Someone really spent a lot on that bit of priceless kit. LOL

    Nice to see the MCBs all nice and straight too. :rolleyes:
     
  7. Tony Goddard

    Tony Goddard Screwfix Select

    I would think one of the generic blank plates would fit the hole, but as said, it needs filling - or get a better CU, as Bazza alluded to Chint is carp.

    My workshop is wired in what is a pretty standard light industrial method of steel trunking around the primeter and everything dropped from that in PVC conduit and metalclad fittings. Steel trunking is cheap and easy to assemble with a hacksaw and 6mm drill, once its in you can add or remove things fairly easily.

    Some pics of mine attached, its been in a good few years now so the fittings are not current but it will give you an idea, my RCD is at the house end, which needs changing as when you do trip it its a PITA to go back and reset.
     

    Attached Files:

  8. Ind spark

    Ind spark Active Member

    18p for a yellow lug?
    Bit steep mate ;)
     
    Tony Goddard likes this.
  9. Tony Goddard

    Tony Goddard Screwfix Select

    Thats inflation for you!! still cheaper than halfords!!
     
    Ind spark likes this.
  10. SomeOfTheGear

    SomeOfTheGear New Member

    It's all been working fine so happy days.

    Yep, I don't mind a bit of fettling but this is above my pay grade!
     
  11. SomeOfTheGear

    SomeOfTheGear New Member

    Intrigued about the big red light!
     
  12. Coloumb

    Coloumb Screwfix Select

    @SomeOfTheGear ooi that all like fairly new and no decent spark would do work like that. When you bought the house what sort of information where you given about part p certs, or indeed lack of them?
     
  13. Bogle Crag

    Bogle Crag Screwfix Select

    It comes on when the bank balance drops below a million
     
  14. Ind spark

    Ind spark Active Member

    Can't do it would be off, he's a spark remember ;)
     
  15. Tony Goddard

    Tony Goddard Screwfix Select

    Its there because I have a habit of forgetting to turn things off (especially the soldering iron and compressor), so when I moved into this workshop I put all the sockets on a contactor (below the little CU) when I come into work I hit the green button, everything comes on including the red lamp (which is an old telephone exchange fault warning lamp), when I lock up in the evening, if I forget to switch off the power, as soon as I turn off the lights the red glow reminds me to do so.

    We do a similar thing in schools with a red bulkead above the DT / Science / Cookery room doors in the corridor to let the caretaker know if the power is left on!
     
    SomeOfTheGear likes this.
  16. bright_Spark

    bright_Spark Screwfix Select

    Two RCDs connected together and possibly even 3, as whoever installed this monstrosity to your workshop may have taken the feed from another CSU with an RCD also. Possible over sized RCDs for the cable, different manufacturers at each end, it all adds up to a terrible job. It looks a complete mess from the outside so god knows what the inside looks like. Another DIY disaster looking at it. Cable exiting through an air brick is another big giveaway. Without trying to rain on your parade mate, You need to get it checked out by a qualified spark before attaching any wood working machinery to that. If you want it doing properly as you say then it looks like a start over again type of job and ignore what is there.
     
    SomeOfTheGear likes this.
  17. SomeOfTheGear

    SomeOfTheGear New Member

    Not bothered about the rain! No point in asking then getting ****** of with the replies from competent people. The previous owner was a builder and built the house. I suspect he did most of the Electrics as well and (possibly) got it signed off by a tame Sparks mate. It's up on the Isle of Skye and there is what's locally termed as "Crofter's Electrics". It appears that this is a good example. There's been a few other things that've caught my attention;
    • twisted earths with no sleeving not connected to anything
    • metal switch boxes with no earth connected (see another of my posts) lighting with earths snipped off
    • quite a lot of old halogen lights with daisy chain joints held together with connectors and cheap plastic tape.
    • a lot of the cable runs are in the combes between the ground and first floor. they just look like a snake's wedding in places which does not inspire confidence.
    I'm a pretty competent general DIYer, BUT the blue sparky stuff is where I tend to tread carefully. Happy to run a fused spur but this sort of stuff is for someone qualified I think. It's frustrating that the person who has to sort out all this bodging is the one that has to pay the price for a decent sparks for it to be made good. I think I'll get recommendations for a Sparks up here and have the whole lot checked over ASAP.
     
  18. bright_Spark

    bright_Spark Screwfix Select

    Nice to see you are a responsible person, pity you didnt post this last week as I have just returned from Skye, would have gladly popped in to give it a look over for you. Anyway to give you good advice from a registered spark, here goes. The cable would need to be armoured, now dependant upon load will determin the size it would need to be. As an example of many home type workshop loads, a 6mm T&E is about the minimum you will probably require, once again distance plays a part here but I am talking of an average length of aprox 20 to 30 meters to your workshop? A 10mm would be better and give you a little more wiggle room. Doubt you will need anything more substantial for a home workshop. This cable could be bought and installed by yourself to save a bit of money here. A spark could terminate both ends and test it for you, this then gives you a good start to do what you want in your workshop. An armoured cable terminated at each end correctly connected to your mains is the biggest expense you are facing with this.
     
  19. Coloumb

    Coloumb Screwfix Select

    You should have been given what's called an EIC which shows compliance with 7671, which it sounds like you don't have. Failing that then the BC completion certificate from the vendor. It's an absolute question that comes up and any decent conveyancer should have pointed it out to you that they are/were missing. So it's great to see the system is working perfectly :(
     
  20. Coloumb

    Coloumb Screwfix Select

    Would you be happy to issue an EIC for that if you had no visibility of how the cable was installed?
     

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