A New Home Workshop, Part 7

In a workshop – home or otherwise – the efficient layout of the power and light is of great importance. Here’s how it was done.

Power

After considering carefully the potential internal layouts within the 12 x 8 metre space, and so the required location of power-points, I decided on the following approach:

·       12 double power-points mounted around the walls at waist level

·       One floor-level power-point for a rainwater pump

·       One 15-amp power-point, positioned high on a wall for a hoist

·       Five hanging power-points, suspended from the roof

·       One single weatherproof power-point mounted on the outside wall of the shed

The internal double power-points are not distributed evenly around the periphery of the shed but instead are located more densely where machine tools will be placed.  

The wall power points are mounted on rectangular pieces of polypropylene (cut up kitchen chopping board) screwed to the top hat girts.

The hanging power-points (that experience shows will be among the most frequently used of all the power-points) are expensive but very useful. Suspended on long chains, they avoid the requirement for extension cords to run across the floor and are easily accessible, even with a lot of stuff mounted against the walls of the shed. They are placed 200cm above floor level – high enough not to be walked into, but still low enough to be easily reached.

The wall-mounted power-points are wired in two circuits, each protected by a 20 amp combined safety switch circuit breaker (RCD / MCB).  The 15 amp power point has its own 16 amp safety switch circuit breaker. The external and hanging power points are wired into another 20 amp breaker. This gives four power circuits, each with its own RCD / MCB.

All power wiring is in 2.5 square millimetre copper cable.

Lights

In my previous 14 x 6 metre home workshop, I used 12 suspended HID lights, each running a 150W metal halide globe. These were switched in two groups of six. The choice of these lights was made after experimenting with a variety of light sources.

In addition, I used three suspended 48W compact fluorescent lights – these were used when instant illumination was required (the HID lights take some time to come up to full brilliance), and when less intense illumination was needed (like when I just wanted to get something from the shed at night).

This approach worked extremely well, the HID lights giving a measured illumination of over 500 lux right through the workshop. I therefore decided to use a similar approach with the new workshop – that was easy to do, as when I moved house, I kept all the HID lights!

This time, for the lower level lighting, I went for two 20W compact fluorescents that feature inbuilt diffusers.

In addition, I placed a twin 500W externally mounted floodlight aimed at the yard.

The HID lights, wired into place with 2.5 square millimetre cable, run circuit protection comprising a 16 amp RCD / MCB.  These lights are switched in two banks of six.

The internal compact fluorescents, and the external floodlight, are connected with 1.5 square millimetre cable and are operated via two switches. These are wired to a single 10 amp RCD / MCB.

Heaters

Where I live it gets (for Australia at least) cold in winter. However, it is difficult to heat such a large volume (around 500 cubic metres) that lacks any kind of insulation. So I chose to not heat the volume, but to heat only me.

To do this, I used three suspended radiant heaters. These are each 2.2kW, three-bar designs that I picked up for $20 each at a second-hand shop.  With a good clean (requiring disassembly), the reflectors came up beautifully and with a 2.2kW output (over double a conventional single bar radiator) they pump out plenty of heat.

The heaters, suspended 2.3 metres above the floor, are mounted as follows:

·       One located ahead of where the hoist is expected to go (the logic being that I intend spending lots of time working in engine bays and around the front of cars)

·       One mounted over my work bench, and another over my welding bench

A fourth I decided to keep as a portable heater – the idea is to mount it on a solid, tall stand so that it can be moved around as necessary.

The heaters are wired into place with separate runs of 2.5 square millimetre cable, and are switched with three switches. They are wired to three 16 amp RCD / MCB units.

Fan

I mounted a large oscillating fan high on one wall. This is fed power from a socket switched from the main board. The socket is wired into place with 1.5 square millimetre cable.

Main Board

The circuit breaker board, all the switches and one of the double power points are mounted on a single piece of thick plywood located next to the personal access door. This makes it easy to switch everything off as you leave the workshop.

From left to right, the switches are for:

-       Three suspended heaters

-       Outside floodlight and inside fan

-       High intensity discharge lights

-       Compact fluorescents

The plywood panel is hinged on one side, allowing it to be swung open for wiring changes.

Shopping list

If you have been keeping count, you will have noticed that the shopping list for the electrics is certainly adding –up.  Thirteen double power points, nine circuit breakers, five hanging power points, hundreds of metres of cabling…

I estimate that at my local hardware store, the bill for parts alone would have been something like AUD$3,000. However, I paid about one-third of this by taking two approaches:

·       Buying goods second hand. For example, the powerful exterior floodlight was bought at a garage sale for $20 and needed only to be mounted on a bracket.

·       Watching eBay for people selling off new bits left over after a major job (the five hanging power points), and for low cost lighting (the two 20W compact fluorescents)

·       Buying most of the stuff (power points, conduit, cable, etc) from an electrical wholesaler.  I used Kalmarc Electrical Industries, Unit 3 / 191 The Horsley Drive, Fairfield NSW 2165, phone 02 9726 3111. To give you an idea of price relativity, from this wholesaler a length of conduit was about 25 per cent of the cost being charged by my local hardware store. That certainly made the 450km round trip to the wholesaler worthwhile!

The main parts used in wiring the workshop are shown in the following table.

No.	Item	Comments
13	Double power points	12 wall mounted + 1 for pump at ground level
1	15 amp single power point	High mounted for hoist
5	Hanging power points	Suspended from roof 2m above floor
1	External weatherproof single power point
1	Single gang switch	For compact fluorescent lights
2	2-gang switches	For individual control of outside floodlight and inside fan, and control of two banks of HID lights
1	3-gang switch	For individual control of suspended heaters
17	35mm deep mounting blocks	For mounting of power points and switches
14	Non-switched surface mount sockets plus bases	Allowing plug-in of HID lights, fan & external light
10	Ceiling roses	For wiring heaters,  compact fluorescents and hanging power points
2	Inline bayonet light sockets	For suspended compact fluorescents
1	Single pole RCD MCB 10 amp	For external floodlight,  internal compact fluorescents and fan
3	single pole RCD MCB 20 amp	For power point circuits
5	Single pole RCD MCB 16 amp	For 15 amp power point, heaters, HID lights
1	18 pole surface mount enclosure	Shed sub-board
1	1 pole main switch 63 amp	Main on/off for shed sub-board
3	3 x 100 metre rolls 2.5mm earth plus twin cable	Used for all power point circuits and HID lighting circuits
1	100 metre roll 1.5mm earth plus twin cable	Used for external floodlight, fan and internal compact fluorescents
2	15 metre, 15 amp ‘caravan’ extension cables	Used to form the feeds for the hanging power points, heaters and fluorescent lights. (Cheaper to buy as extension cables than bare cable!)
1	25 metre roll 25mm corrugated conduit	Used to form bends between hard sections of conduit
30	4 metre lengths 25mm conduit grey	Large amount used as all wiring in shed run in conduit
130	25mm conduit joiners	Large number used as these work in conjunction with flex conduit to form bends
150	25mm half saddle conduit clamps
200	Assorted self-drilling fasteners
2	20 watt compact fluorescents
12	150W HID lights	Previously purchased second hand and then equipped with new bulbs
3	2.2kW suspended electric radiator heaters	Purchased second hand and then overhauled
1	Twin 500W exterior floodlight	Purchased second hand and then matched to new mounting bracket
1	Fan	Wall mounted oscillating

Installation

A major issue with wiring such a tall shed is access.

The conduit runs on the walls could be done using a tall extension ladder, but the roof wiring required the hiring of a 4 metre scaffold – it was simply too dangerous to work on a ladder when you needed both hands free.  The hire of this scaffold cost $360. Note that the disassembled scaffold can easily be fitted on a normal car trailer (pictured).

The wiring took many hours to complete but didn’t require any cash outlay. (Of course, here in Australia, wiring should always be supervised by a licensed electrician.)

Conclusion

In terms of time and cost, the electricals formed a major component of the total workshop effort. However, the ease of use of the workshop, and the ability to work at night, make it worthwhile!

Pluses:  Great lighting and power distribution; adequate heating and cooling Minuses: It takes a long time to do cable and conduit runs when working high on a scaffold. The Surprise: Shop around and save 75 per cent in electrical parts prices! Cost: Parts - $1300 Scaffold hire - $360

Next issue: a unique solution for storage

The parts in this series: Part 1 - Clearing the space Part 2 - Planning the design Part 3 - Gaining planning authority approval Part 4 - The concrete slab Part 5 - Getting the shed erected Part 6 - Stormwater handling Part 7 - The electricals Part 8 - Organising storage Part 9 - Building the workbenches Part 10 - Evaluating the outcome

Interested in home workshop projects and techniques? You’re sure then to be interested in the Home Workshop Sourcebook, available now.