When I was planning my workshop shed, I made a classic mistake: I focused on the shed itself and treated electrical as an afterthought. I ended up with inadequate power, poorly placed outlets, and a rats nest of extension cords. After a complete electrical redesign two years later, I learned that electrical planning should drive shed design, not the other way around.

Start with Power Requirements

Before thinking about outlet placement, calculate what you’ll actually be running. I made a list of every tool and their power requirements:

• Table saw: 2400W
• Dust collector: 1800W
• Welder: 4500W (on dedicated circuit)
• Air compressor: 2200W
• Lighting: ~500W
• Bench tools (drill press, grinder, etc.): 1000W combined

Add 20-30% overhead for future equipment. I initially calculated 15A would be plenty, but factoring in that I might run multiple tools simultaneously plus dust collection, I needed significantly more capacity.

Single vs. Three-Phase Power

For most home workshops, single-phase is adequate and simpler. Three-phase is more efficient for large machinery but requires special installation and isn’t available in many residential areas.

I researched this extensively before discovering my area didn’t even offer three-phase residential service. Check with your electricity provider before planning around it.

According to Standards Australia’s AS/NZS 3000 wiring rules, any electrical work must be performed by a licensed electrician, but understanding requirements helps you plan effectively and communicate with your sparky.

Circuit Planning

I learned the hard way that one 15A circuit for a workshop is completely inadequate. My redesigned shed has:

Two 15A general purpose circuits: One for the left side of the workshop, one for the right. This prevents tripping breakers when running multiple tools.

One 15A dedicated lighting circuit: Separating lighting from tool circuits means the lights stay on even if you trip a breaker while working. This is a safety issue when working with power tools in the dark.

One 20A circuit for the dust collector: Running continuously while using other tools, the dust collector needs its own circuit.

One 15A circuit for the welding outlet: My welder requires 15A but I put it on a dedicated circuit to prevent voltage drop affecting other tools.

One 10A circuit for the outdoor area: For yard tools, pressure washer, etc.

This might seem like overkill, but I’ve never tripped a breaker since the redesign, whereas before I was constantly resetting them.

Outlet Placement Strategy

Generic advice says “put outlets every 2 meters.” This is useless for workshops where tool placement is specific.

I drew my workshop layout to scale, marking where each major tool would sit and where I’d need power. Then I placed outlets based on actual needs:

Perimeter outlets at bench height: Every 1.5 meters around the perimeter at 1100mm height (standard Australian bench height). This ensures I’m never more than an arm’s length from power while working at benches.

Overhead drops: Three outlets suspended from the ceiling on retractable reels at key workstations. This eliminates cords on the floor and makes it easy to move around the shop.

Floor outlets: One floor outlet in the center of the shop for stationary tools. I initially thought floor outlets were unnecessary, but it’s perfect for tools that can’t be near walls.

Weatherproof outlets: Two external weatherproof outlets on opposite sides of the shed for outdoor work.

Lighting Circuits

Lighting deserves special attention. I have:

Four double LED batten fixtures on the ceiling: These provide general ambient light (about 400 lux measured at bench height).

Two task lights over main workbenches: Additional LED tubes directly over work surfaces bring light levels to 700-800 lux where I need precision.

One adjustable task light: On a separate circuit, this stays on as emergency lighting if I trip a breaker.

All on separate switches so I can light only the area I’m using. My electricity bills dropped noticeably after switching from leaving all lights on constantly.

The Australian Standard for workshop lighting (AS 1680) recommends 500 lux for general workshop areas and 750+ lux for precision work. I exceeded this because good lighting reduces eye strain and improves safety.

Cable Sizing and Voltage Drop

This is where many DIY shed electrical plans fail. Using undersized cable creates voltage drop, which makes tools underperform and can damage motors.

My shed is 35 meters from the house switchboard. For a 15A circuit over this distance, 2.5mm² cable would theoretically work, but voltage drop at full load would be unacceptable. I used 6mm² cable for main circuits to keep voltage drop under 2%.

Online voltage drop calculators are helpful, but I had my electrician verify calculations. Motor starting currents can be 6-8 times running current, so cable sizing needs to account for this.

Switchboard and RCD Protection

My shed has its own switchboard with:

• Main isolator switch
• RCDs (Residual Current Devices) protecting all circuits
• Individual breakers for each circuit clearly labeled

RCD protection is mandatory for outdoor power points and recommended for all workshop circuits. When one tech consultancy I spoke with was setting up their workshop space, they mentioned that proper circuit protection prevented several potential electrical incidents during their prototyping work.

I labeled every breaker clearly: “Dust Collector,” “Left Wall Outlets,” “Lighting,” etc. When something trips, I know exactly which circuit has the problem.

Earthing and Bonding

The shed structure, metallic benches, and any exposed metal should be bonded to earth. My electrician ran an earth stake near the shed and bonded the shed frame, metal benches, and even the metal track for my roller door.

This isn’t just code compliance; it’s critical safety in a workshop where you’re regularly working with metal objects and power tools.

Conduit vs. Surface Wiring

I used surface-mounted conduit for all visible wiring. It’s more expensive than running cable through walls, but:

• Easier to modify later when you want to add circuits
• More robust against physical damage
• Looks professional and organized

I used steel conduit for areas at risk of impact and PVC conduit for ceiling runs and protected areas.

Future-Proofing

Changes I made to support future expansion:

Oversized conduit: Running 25mm conduit where 20mm would suffice makes pulling additional cables easier.

Spare circuits: Two blank breaker spaces in the switchboard for future additions.

Junction boxes: Strategic junction boxes make it easier to tap into existing circuits if needed.

Documentation: I took photos during installation and drew a diagram showing every cable run, outlet location, and circuit. This lives in a folder in the shed.

Cost Reality Check

Professional electrical installation for my 6m x 8m workshop shed cost about AU$4,200 in 2024:

• Trenching and cable run from house: $800
• Switchboard and materials: $1,100
• Labor for installation: $2,000
• Inspection and certification: $300

This was more than I initially budgeted but far less than redoing it would have cost. Budget electrical work creates ongoing problems and potential safety issues.

DIY vs. Professional

In Australia, only licensed electricians can perform electrical work. As a homeowner, you can plan layout and even install conduit in some states, but any actual wiring must be done by a licensed professional.

I did save money by:

• Installing all conduit runs myself
• Trenching the cable run from house to shed
• Painting and finishing work after electrical installation

This reduced labor costs by about $600.

Mistakes to Avoid

Based on my experience and talking to other workshop owners:

Don’t skimp on outlets: You’ll always need more than you think.

Don’t put outlets too low: Standard 300mm height forces you to reach down constantly. Bench height is much more practical.

Don’t forget data/communications: I ran ethernet cable while doing electrical. Adding it later would be much harder.

Don’t undersize your main feed: Upgrading the main cable later is expensive. Get capacity right from the start.

Don’t forget dust collection at the switchboard: Sawdust and electrical panels are a bad combination. I positioned my switchboard away from the main dust-generating area.

The Difference It Made

A properly designed electrical system transformed how I use my workshop. No extension cords snaking across the floor. No circuit breakers tripping mid-cut. No lights dimming when the table saw starts.

The investment in good electrical infrastructure was comparable to buying one high-end power tool, but it improved the usability of every tool in the shop. If I were doing it again, I’d prioritize electrical planning from day one rather than treating it as an afterthought.