Workshop Power

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Workshop Power

This project is to install 3 phase power in the workshop area of the Hackspace, to replace the use of a temporary flexible cable which can only feed one item at a time.

We already have the Bridgeport Mill and a Donkey Saw which require 3phase power, but with the installation of proper infrastructure we will be able to run more powerful welders (TIG and Arc), and other tools we may get in the future - perhaps a better air compressor.

We also need 3phase to run a motor / fan that we have for dust extraction. In addition to 3phase power, some higher-current single phase outlets are needed for welding equipment that we have. Including these in the project will reduce the reliance on 'domestic' 13A sockets for these items.

Key Dates: Creation of project page 21st August 2013

link to mailing list or somesuch

Project Contacts

  • David Clarke (Page creation, general guidance as to project direction)
  • Matt Lloyd (interest in metalworking area tooling, and installation of the wiring)
  • Chris Cain


14/03/2014 Dist Board upgrade completed SWA Run in and connected: 3 Phase power now available at Workshop sub Dist board Single phase ring install started Locations of initial 3 phase connections decided.

Updated Plan for discussion

Investigation of the current main DIST boards

Current Usage is shown on

Wall is now in place and Dist board is mounted

The plan is:-

3 * 16 A 5pin Commando sockets with RCD + Isolator mounted:-

  • Above Bridgeport
  • Near Donkey Saw
  • Near corner of new wall and back wall
  • ADD: one in the dusty area for dust / chip extraction, and one extra for a possible improved air compressor. We have the parts needed. Dclarke (talk)

Dedicated fixed supply to Large DialArc welder, hard wired with isolator (We have a 63A socket / isolator as an alternative to fixed wiring).

Single phase consumer unit from one phase to provide 2 single phase rings one for MW side + one for CNC/Laser cutter side - exact socket positions TBD No need for a separate CU/dist board for the single phase there should be enough room in the new workshop 3phase dist board for a few single MCB's --'RepRap' Matt

Plan is to reuse the 4mm SWA currently used for the run from Main Dist to end point above workshop door for to wire the Commando Sockets. This cable has 'old' colour codes but this is not really an issue. We could scrap/rebuy some 4mm SWA for this if we really care about the colour code extra cost would be about £60 for the new cable minus a few pounds in scrap for the old.

The new dist board needs a connection back to the main dist board. This is approx 40 meters, we will use 4 core 16mm^2 SWA for this which allows for 80A per phase usage (100KW draw) which should be adequate.

Shopping list of required kit to complete project

Our Expected initial usage is:

Dev L1 L2 L3
Bridgeport 5 5 5
Hacksaw 3 3 3
Welder (TIG) 48 48 0
S/P Rings 0 0 32
Addnl 3ph 16 16 16
Totals 72 72 52

The tig welder is slightly unknown!, the manual Is for the USA 200/480V unit and I have used the total power draw (20Kva) to get the 415v current, this will be a worst case number, actual is likely to be significantly lower.

Back rating plate on the Tig has the highest rating shown as 77A at 415V (for AC TIG) --'RepRap' Matt

This current Draw (72A) would indicate 16mm cable but real world usage we are not going to have bridgeport + full current welding + hacksaw +additional 3 phase in use all together !!

In real life 59A/Phase is in my opinion more than we will ever actually need. so unless someone has another view the plan is for 10mm.

I was also thinking about permanently wiring the blue MIG welder to the 3 phase. It like the Tig has a Phase to Phase option, I'm not sure of the rating will have to look it up but I don't think it will be that big a load in comparison. This could just go on the "Additional 3 phase socket" but I doubt it will add much more to the cost to add an extra run. --'RepRap' Matt

The other issue is connection into the main dist board. At present we have a (guessed) 125A input supply this is split vial a main isolator into 2 isolated dist boards with 60A isolators.

To connect in the new Workshop dist board there are a number of options but the cheapest would be to remove dist board2, move the (not many) points on that over to dist 1 and reuse the existing 60A isolator to feed the new workshop dist board.

This needs a reasonable amount of work but no new kit. It would need a half day or so of 'no power in the space' to do the work.

The alternative would be purchase a new isolator to feed the WS dist board and add it. This would be simpler but a new 60A Fused Isolator is £290.26 Here, or £95+ Used here Dclarke (talk)

or £508.44 for a 100A unit

Give the cost it might be worth just going with an isolator as currently used in the building, 100A iso would be £294 from here or £150 from ebay --'RepRap' Matt 15:55, 23 February 2014 (EST)

The 60A unit is good for 10mm cable, the 100A for 16mm Cable. the exiting one that could be re-used by rewireing the dist2 board is a 60A unit.

There is becoming some urgency in completing this project. The wall between the metalworking area is about to be constructed - necessary to keep grinding and welding dust away from the laser cutter area - is about to be built, and then we will have no excuse for not being able to run the heavier machinery using 3 phase power.

Monday 17/2/2014 - while waiting for arrival of materials for the wall, let's get some accurate measurements of the cable runs required.

Other Stuff

Power requirements of tools we have

Bridgeport Mill (16A / 3phase)

TIG welder (70A / Single phase 415V)

Extraction fan motor

Power requirement of tools we might get

Length of supply cable

30 metres from the main switch area (cupboard in the Blue Room) along the South wall to the Workshop area. (N.B. needs checking, as this cable is available cut to the metre length)

Outlets required

16A/3 for Bridgeport 16A/3 for Donkey Saw Direct wiring to distribution board for TIG welder 32A/2 for Arc welder (guess, but we have these connectors already from Bridgeport) 16A/3 for Dust fan 16A/1 for MIG welder

Possibly switched outlets that can be padlocked to control access to 'needing induction' tools.

Other stuff

We have a quantity of donated cable, which was originally used to connect the 16A/3 socket outlets that we have. As this is 'old colours' it is probably best to scrap this (could get £90) and use the money to fund the purchase of modern multicore flexible for the socket wiring around the workshop.

Distribution boards available.

1. 12 x 3phase ways / 100A incoming isolator.

  6 - MEM 16A type 3 single phase MCBs
  9 - MEM 16A/3 type 3 3phase MCBs

2. 16 x 3phase ways / 100A incoming isolator.

  1 - 63A/3 3phase MCB
  4 - 40A 3phase MCBs
  5 - 32A/3D 3phase MCBs
  2 - 32A/3C 3phase MCBs
  7 - 20A/3C 3phase MCBs
  1 - 20A/1 single phase MCB

In addition we already have 2 32A, 2 16A and 1 6A RCCBO for protection of single phase cicuits.


Distribution board and MCBs - Donated, though we may need some different MCBs 3phase 16A socket outlets - Donated, though these are non-switched. Otherwise £20 each, or £10 to add switches. 30 metres of 10mm² SWA 4-core cable + glands £130 Single-phase 16A socket outlets from £7 ( Single-phase RCCDOs we have.

Some photos perhaps? Awaiting these.

Metalwork Area wall

(Dclarke 07:26, 7 March 2014 (EST)) Studding and lower panelling in place Feb/2014. Polycarbonate sheet arrived today (Fri/7/Mar/2014)

Cutting and fitting the glazing sheet - a sub-task of the electrical installation tomorrow if it DOESN'T GET IN THE WAY!

Method - please follow carefully.

1. Check the exact size of the sheet - it should be 3000mm x 2000mm but this can be +/- 25mm, and mark a line dividing into two lengths approx 300mm x 1000mm

2. Cut using the 14tpi handsaw, or a jigsaw with fine metal cutting blade, supported on lengths of timber or across tables in the studio. Vacuum up afterwards!

3. One piece should fit one of the sections in the wall, the other will need shortening by about 600mm - this offcut to be labelled as it will be useful for machine tool guarding.

4. Drill 6mm holes where fixing screws are to go into the top rail of the window openings. Suspend the sheet from the top rail with a few screws, using an offcut of 3mm stuff to rest the bottom on in the window 'frame'.

5. Cut some 3mm ply (50mm or so wide) to go over the vertical rails. Drill through these and the sheet 4~5mm, then open out the holes in the plastic to 6mm. This over-size is necessary to accommodate expansion due to heat.

6. Clamp the ply and sheet to the frame with 5mm screws. Then remove suspension screws and repeat the exercise top and bottom. Do the seconds 'window' similarly.

Page based on template suggested by Michael Erskine