Powering Your Shed or Workshop Safely: An Australian Planning Guide

Why Shed Power Deserves a Proper Plan

A shed or workshop is only as useful as the power running to it. A single extension lead from the house might charge a drill battery, but it won’t safely run a table saw, a compressor and a row of lights at once.

Getting the electrical plan right at the start saves money, prevents tripping breakers and, most importantly, keeps you safe. Whether you’re building a new Colorbond shed, converting a garage into a workshop or kitting out a backyard studio, the same five questions apply: how much power can your property supply, what your switchboard can handle, what you’ll be running, how you’ll light the space, and which mistakes to avoid.

One point up front: in every Australian state, fixed electrical wiring must be installed by a licensed electrician. This guide will help you plan and ask the right questions, not do the wiring yourself.

1. Start With Supply Capacity

Your shed can only draw what your property’s electricity supply can deliver. Most Australian homes have a single-phase supply, while some rural and larger suburban properties have three-phase power. The size of the main fuse or service protection device sets the ceiling for everything on the property, including the house.

Before you buy tools, find out:

• What type of supply you have. Single-phase is fine for most hobby workshops. Three-phase becomes worth considering for large machinery, commercial-grade welders or a big compressor.
• How much spare capacity there is. If the house already runs ducted air conditioning, an induction cooktop, a pool pump and an EV charger, there may be little headroom left for the shed.
• How far the shed is from the switchboard. Long cable runs suffer voltage drop. Under AS/NZS 3008 cable selection rules, the cable must be sized so voltage stays within limits at the far end, which often means heavier, more expensive cable for a shed at the back of a big block.

When the Supply Itself Needs Work

Sometimes the property’s supply simply isn’t big enough, or the service line into the property is old. Upgrading the connection to the electricity network, or adding a new underground or overhead service, is specialist work. In NSW it must be done by an Accredited Service Provider. If you’re in Sydney, a Level 2 electrician in Sydney can assess your service mains, upgrade the connection and confirm how much capacity you have to work with.

Rural and semi-rural properties often have another consideration: the shed may be fed from a private power pole on the property. Private poles are the owner’s responsibility, not the network’s. Before you hang a new overhead line to the shed or add load to an existing one, have the pole inspected for rot, lean and termite damage. A failing pole is a serious hazard, especially in storm season.

2. Check Your Switchboard and Plan a Sub-Board

The main switchboard is where the shed’s power starts. Older boards with ceramic fuses, no safety switches or no spare space are a common roadblock. Many electricians will recommend a switchboard upgrade before adding a significant new load.

For anything more than a light and a couple of power points, the usual approach is a dedicated submain from the main board to a sub-board inside the shed. This gives you:

• Separate circuits for lights, general power points and heavy equipment, so one tripped circuit doesn’t plunge you into darkness while holding a running tool.
• Local isolation, so you can switch off the whole shed without walking back to the house.
• Room to grow, with spare positions for future circuits such as an air conditioner or a second welder outlet.

Safety Switches and Surge Protection

Under the current Wiring Rules (AS/NZS 3000), new final subcircuits for power and lighting in homes need 30 mA residual current device (RCD) protection. In a shed with concrete floors, metal walls and the occasional wet boot, safety switches are non-negotiable.

Ask your electrician to split circuits across more than one RCD so a single fault doesn’t kill everything. It’s also worth discussing surge protection if you’ll run computers, CNC machines, battery chargers or inverter-driven tools, which are sensitive to voltage spikes.

3. List Your Equipment Loads

Write down every tool and appliance you expect to use, then note which ones will run at the same time. That second step matters more than the total. A drop saw and a dust extractor running together is a realistic peak; every tool in the shed switched on at once is not.

Typical loads for common workshop gear (approximate, always check the compliance plate):

What This Means for Your Circuits

Standard 10 A power points suit most hand tools. Welders, larger compressors and some table saws come with 15 A plugs, which physically won’t fit a 10 A outlet, and they need a matching 15 A outlet on an appropriately rated circuit.

Motors also draw several times their running current for a split second when they start. That’s why a compressor kicking in can trip a breaker that handles the saw comfortably. Your electrician will size circuits and breakers with this in mind.

4. Plan Your Lighting Properly

Poor lighting is one of the most underrated safety risks in a workshop. Shadows over a blade or a dim corner where offcuts pile up are how accidents happen.

• Use LED battens or high bays. They use a fraction of the power of old fluorescent tubes, start instantly in cold weather and don’t flicker.
• Layer your light. Aim for even general lighting across the floor (roughly 300–400 lux for a working shed) plus brighter task lighting over the bench and machines, where fine work may need 600 lux or more.
• Choose a neutral to cool colour temperature. Around 4,000–5,000 K makes it easier to read measurements and spot defects.
• Avoid stroboscopic effects. Poor-quality lighting can make spinning blades look slower or stationary. Quality LED drivers reduce this risk.
• Think about switching. Switch near every door, a separate switch for bench lights, and sensor lights outside for walking to the shed at night.
• Consider emergency or battery-backed lighting if you work late, so a tripped circuit doesn’t leave you in the dark beside a coasting machine.

5. Common Planning Mistakes To Avoid

1. Running the shed off an extension lead. Leads aren’t designed for permanent use, overheat when coiled and are easily damaged by doors and vehicles.
2. Undersizing the submain. Saving on cable now means voltage drop, nuisance tripping and an expensive replacement when you add equipment later.
3. Too few power points. Plan more outlets than you think you need, at bench height, along every wall. It’s far cheaper during the build than after the lining goes up.
4. Putting everything on one circuit. Separate lighting, general power and heavy equipment.
5. Forgetting future loads. An air conditioner, EV charger, kiln or second welder may be on your wishlist. Leave spare capacity and spare sub-board positions.
6. Ignoring the route of underground cables. Cables must be buried at the correct depth, in conduit, with marker tape. Record the route so no one digs through it later.
7. Overlooking the overhead supply. Running a new overhead line to the shed, or loading up an old private pole, without checking clearances and pole condition.
8. Skipping weather and dust protection. Use outlets and fittings with an IP rating suited to the location, especially near roller doors, wash-down areas and sawdust.
9. DIY wiring. It’s illegal in Australia for unlicensed people to do fixed wiring, and it can void your home insurance.

6. Compliance and Working With Your Electrician

All fixed electrical work in a shed must meet AS/NZS 3000 and be carried out by a licensed electrician. When the job is finished, your electrician must give you a certificate of compliance. In NSW this is the Certificate of Compliance for Electrical Work (CCEW). Keep it with your property records, because insurers and future buyers may ask for it.

To get an accurate quote, give your electrician:

• A sketch of the shed showing doors, benches and where each machine will sit
• Your equipment list with plug types and power ratings
• The distance from the house switchboard to the shed
• Any plans for future additions such as air conditioning, solar or an EV charger

If work on the street connection, service mains or a private pole is needed, check that the electrician holds the right accreditation, or can bring in someone who does.

Shed Power Planning Checklist

• Confirm supply type (single or three-phase) and spare capacity
• Check the main switchboard has space and modern safety switches
• Plan a dedicated submain and a sub-board in the shed
• List every tool, its plug type and what runs at the same time
• Separate circuits for lighting, general power and heavy equipment
• Mark 15 A and higher outlets for welders and compressors
• Lay out general and task lighting, switches and outdoor sensor lights
• Leave spare capacity for future loads
• Have any private power pole or overhead line inspected
• Use a licensed electrician and keep your compliance certificate

The Bottom Line

A well-planned shed is safer, more productive and cheaper to run. Work out what your supply can deliver, give the shed its own sub-board, size circuits around real equipment loads and light the space properly. Bring a licensed electrician in early, ideally before the slab is poured, and your workshop will be ready for the tools you own today and the ones you’ll buy next.