Power/works list

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Revision as of 17:10, 24 April 2013 by AlisonW (talk | contribs) (cable colour codes)
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Task list to get 'new' electrics all working; please strike through entries as they are completed.

Enabling works

  • Fit cable tray in basement
    • Check with Solexious how much extra weight will be needed for his warning light cable - extend tray towards stairs if required
  • Cut slot and holes in galvanized steel trunking length, as marked, tape edges of large slot
    • attach swa termination fittings to each of the holes on the top, ready to receive cables later
    • attach trunking to wall above new distro box
  • Rewire 3ph connection from our main switch to splitters and then to existing fuse box and our new distro box

Armoured cable works

  • The cable coming through to upstairs by the office became shortened while being cleated to the wall and needs to be replaced.
    • The cleats are not tight on the cable so it can be just eased through - it will be re-used downstairs
    • position the reel of 16/3 swa upstairs where the 'CU' is marked on the wall. Pull through cable via the cleats to downstairs and out to the new distro box
    • ensure cable long enough before cutting (needs full-size hacksaw)
  • Enlarge (or make new) hole in ceiling of metal workshop through to riser adjacent to lift shaft (Sol can show where)
    • feed 10/3 swa through this hole *from downstairs* and pull through, first through a new hole on ground floor to be drilled just above the riser's cover.
    • Then cleat up and over the corridor until it reaches the sub-box already attached on the outer wall of the classroom. Cable should reach to bottom of box.
    • once upstairs is fitted, downstairs pay out cable and lay along cable tray until new distro box is reached -
      • cable fixes via trunking, cut for length though to equal *bottom* of new distro box
  • Re-use 16/3 swa cable from upstairs to reach from new distro box (bottom of) to whichever workshop it will reach to
    • Install new 16/3 swa cable to other sub-box locations in basement (1 fewer then general workshop, wood, metal, bio-wet)
Note - whilst swa will be terminated on top of the trunking, the cables will need to reach the equivalent of the bottom of each box

Sub-distro boxes

  • One to be fitted on outside wall of office, marked [CU]
  • One to be fitted on outer wall of wet lab/biolab, marked [CU]
    • Use 2.5mm T+E from this box to service horizontal line of sockets in biolab at approx 1m height from floor and 24cm spacing
      • Metalclad sockets to suit are already separated for installation in the blue bags in the electrics tray
      • Fit female conduit ends to back boxes before installation, cut 8x 24cm lengths of conduit and build socket line on floor. Hold to wall to mark screw positions. Drill and fit.
      • Ring should be wired on alternate boxes for preference. Ensure earth sleeving is used, especially on short earth leads to boxes.

Cable Colour Codes

  • Once upon a time the colour codes in the UK were black neutral, green earth, red live - phase 1, yellow and blue other two live phases when using a 3-phase supply.

Then along came "European Harmonization" and everything changed. In your home "red-black-green" became "brown-blue-green/yellow" and it wasn't too bad. But in the three-phase world the primary (and easily identifiable) red-yellow-blue became "brown-grey-black" which don't look much different in the semi-dark. Yes, black was now a *live* wire, not neutral. And yea, electricians up and down the land of the Angles got most distraught. Especially when they were laying steel-wire-armoured (swa) cables.

  • At the London Hackspace we have a mix of old and new cables, used for a mix of purposes, because we try to reuse everything to reduce expenditure. This means that you must always check what a wire is being used for and NOT trust the original colour.
  • Where the original colours are red-yellow-blue and it is now carrying single phase then red=live, blue=neutral, yellow=earth
  • Where the original colours are brown-black-grey and it is now carrying single phase then brown=live, black=neutral, grey=earth

Tape will usually be used at each end of the cable to correctly identify the use.

Phase allocation

  • We have a three-phase supply and need to keep our consumption on each phase roughly equal.
  • This means that different areas, even if adjacent, may be on different phases. Do NOT use extension leads from one area to feed equipment in another.