Most container workshops are under-powered. The owner buys the container for storage, decides to add a workbench, then a few outlets, then a compressor — and by year two the breaker is tripping every time the welder runs. Better to plan the electrical scope before delivery, not after.
Here’s the realistic walkthrough for wiring a container workshop right the first time.
The situation
A typical container workshop scenario:
- 20ft High-Cube or 40ft Standard container at a home property
- Owner is a maker, mechanic, woodworker, or fabricator
- Will run hand tools (drills, sanders), power tools (table saw, drill press), and occasionally a welder, compressor, or plasma cutter
- Needs lighting + outlets at bench height + at least one 240V circuit
- Use is year-round, so HVAC is likely (mini-split is the standard answer)
The realistic electrical scope
Three layers, in order of priority:
Layer 1: Subpanel + service entrance
- Subpanel: 60A for storage with lights + a few outlets. 100A for an active workshop. 200A only if you’re running a real fab shop with multiple welders + heavy machinery.
- Service entrance: Run underground from the main panel (or pole) to the container. Conduit, sized for the panel amperage, with the proper wire gauge.
- Grounding: Steel container = excellent ground when connected properly. Bond the container to a ground rod or to the main panel’s ground.
For most workshops, 100A is the sweet spot. Goes far enough to run a welder + lights + outlets + mini-split simultaneously. Doesn’t cost much more than 60A but provides 70% more capacity.
Layer 2: Conduit + branch circuits
- EMT conduit run along the corrugation. Painted steel pipe, easy to attach to the corrugated walls with conduit clamps.
- Romex inside conduit or MC cable direct (both work). Conduit is more flexible for future changes.
- Outlets every 4-6 feet at bench height (42-48 inches from floor). Code minimum is every 12 feet; workshop best practice is every 4-6 feet so you’re never reaching.
- Overhead outlets for hanging tools (drill press, grinder on a swing arm).
Layer 3: Lighting + dedicated circuits
- LED panels overhead: 1 panel per 10 linear feet. Use 5000K daylight color for accurate color rendering in detail work.
- Switched outlets near the door for plug-in supplemental lights.
- Dedicated 240V circuit for the welder, plasma cutter, or air compressor. Even if you don’t have one yet, run the conduit so adding it later is trivial.
- Dedicated mini-split circuit if HVAC is in the plan.
The cost breakdown
For a 100A subpanel + workshop wiring in a 20ft container:
| Item | Cost |
|---|---|
| 100A subpanel + breakers | $300-$500 |
| Service entrance (40 ft underground run, conduit, wire) | $800-$1,500 |
| EMT conduit + Romex (interior wiring) | $200-$400 |
| Outlets + boxes + faceplates (12-16 outlets) | $150-$300 |
| LED overhead panels (4-6 units) | $300-$600 |
| Permits + inspection | $200-$500 (varies) |
| Licensed electrician labor (~12-16 hours) | $1,500-$2,500 |
| Total (DIY rough-in, licensed terminations) | $2,000-$3,500 |
| Total (fully licensed install) | $3,500-$5,500 |
The 40ft version: roughly $1,500 more for additional outlets + lights + conduit runs.
For more on container modifications generally, see our modifications cluster. For the broader workshop conversion guide, see container workshop conversions.
DIY vs. hire
- Hire it entirely: If the workshop will require a building permit (some jurisdictions for workshops, most for container homes), hire a licensed electrician + pull the permit. End-to-end licensed install: $3,500-$5,500.
- Hybrid (most common): Owner runs the conduit + roughs in outlets + lights. Licensed electrician handles the service entrance, the subpanel install, and all the terminations + permits. Saves $1,500-$2,500.
- Full DIY: If no permit is required (storage-grade workshop) and you have real wiring experience, full DIY works. Don’t shortcut grounding. Don’t undersize wire. Don’t skip GFCI/AFCI breakers where required.
The 5 things workshops always wish they did differently
- Bigger subpanel. 60A was enough for storage; not enough for a welder + dust collection running simultaneously. Plan ahead.
- More outlets. Plan double what you think you need. Every project changes which corner needs power.
- Conduit instead of direct-burial Romex. Conduit lets you pull new wire later. Direct-burial doesn’t.
- Dedicated welder/compressor circuit installed from day 1. Adding it later means digging up the conduit run.
- LED panels not shop-light strip lighting. The light quality difference is huge. Panels run cooler too.
Where to start
- Confirm permit requirements. Some jurisdictions require permits for any 240V circuit; some only for dwellings. Call your local building inspector.
- Size the subpanel honestly. List every tool that might run simultaneously + add 25% headroom. Get a 100A panel if you’re between 60 and 100.
- Plan conduit routes BEFORE insulation. Easier to run conduit on bare corrugation than to retrofit through framing + drywall later.
- Coordinate with the insulation step. See our insulation guide — electrical goes in first, insulation goes around it.
For the full workshop conversion picture, see workshop conversions. For workshop use cases generally, see workshop use cases. To spec the right container for your workshop, call us.