A shipping container doesn't come with a single outlet, switch, or circuit. Adding electricity means dealing with metal walls that conduct electricity, grounding requirements specific to steel structures, and NEC codes that most residential electricians rarely encounter. This guide covers everything — power source options, panel sizing, wiring methods that work on corrugated steel, and what the whole job costs.
Hire a licensed electrician for the installation
You can plan the layout, choose the power source, and understand the process thoroughly — but the actual wiring should be done by a licensed electrician. Container electrical work involves metal-structure-specific grounding requirements that most DIY guides gloss over, and improper grounding creates a serious shock hazard. Inspectors also won't sign off on unpermitted electrical work, which matters if you ever sell the property.
In this guide
Step 1 — Choose your power source
Your power source determines everything downstream — panel size, wiring complexity, and ongoing cost. There are three real options for containers.
Grid connection
Most commonBest for
Permanent setups
Monthly cost
Utility rate
Run a feeder cable from an existing building's sub-panel or pull new service from the utility meter. Underground feeder (UF cable) buried in conduit is the standard for permanent installations. Most reliable and cost-effective for containers that stay in one place. Requires utility coordination and permitting.
Generator
Best for
Remote / temp
Upfront cost
$800–$5K+
A 7,500-watt portable generator handles basic lighting, outlets, and a small AC unit. Larger 15–25kW standby generators support full electrical loads including HVAC and equipment. Position generators at least 5 feet from the container and connect through a transfer switch. High fuel cost long-term.
Solar
Best for
Off-grid / low draw
Upfront cost
$3K–$15K+
Practical for LED lighting and device charging in remote locations. A full solar setup with battery storage capable of running HVAC gets expensive fast. Best combined with a generator backup for cloudy periods. Flat container roofs are excellent for panel mounting.
Step 2 — Size your electrical panel
Panel size is determined by your total electrical load. Add up the wattage of everything you plan to run simultaneously, add a 20% buffer for future expansion, then convert to amps (watts ÷ 120 for 120V circuits, ÷ 240 for 240V).
| Use case | Typical panel size | What it supports |
|---|---|---|
| Basic storage / lighting only | 30–60A | LED lights, a few outlets, a small fan |
| Workshop / job site | 100A | Lighting, power tools, compressor, one small AC unit |
| Office or studio | 100A | Computers, monitors, lighting, mini-split AC, kitchen appliances |
| Full home (single container) | 100–150A | All appliances, HVAC, hot water heater, EV charging |
| Multi-container home | 200A | Full residential load across multiple containers |
Tip: always buy one size up
A 100A panel costs roughly $200–$400 more than a 60A panel. Upgrading the panel later after walls are finished means tearing out and redoing work. Always install more capacity than you think you need.
Step 3 — Plan the layout before you insulate
This step is the most commonly skipped — and the most expensive to fix. Your electrical layout must be finalized and wiring routes marked before insulation goes in. Once spray foam is applied or wall panels are installed, accessing the walls to change wiring routes requires tearing everything out.
-
1
Mark outlet and switch locations
Walk through the container and mark every outlet, switch, and light fixture location with spray paint or tape. Consider: outlets near every work surface (every 4–6 feet in a workshop), GFCI outlets in any area near water (kitchen, bathroom, exterior), dedicated circuits for high-draw appliances (mini-split, compressor, welder).
-
2
Choose and mark the panel location
The electrical panel needs to be accessible at all times — it cannot be behind a locked door or above a ceiling. Common locations: near the entry door, in a utility alcove, or in a dedicated mechanical space. Mark the panel location and plan the feeder cable route from outside.
-
3
Plan conduit routes along flat ribs
Shipping container walls are corrugated steel — conduit must be run along the flat sections between ribs, not across the corrugations. Plan routes that minimize bends and offsets. Horizontal runs along the base or ceiling are easiest. Mark routes before framing begins so the electrician can install conduit before walls are closed.
-
4
Mark penetration points
Any penetration through the container wall (for the feeder cable, outdoor outlets, or exterior lighting) must be drilled and fitted with watertight conduit fittings before painting or insulating. Mark every penetration point so they can be drilled cleanly with proper grommets to prevent cable abrasion on the steel edges.
Step 4 — Choose a wiring method
Standard residential wiring methods don't all work on container walls. The corrugated steel surface, moisture exposure, and NEC requirements for metal enclosures narrow your options.
EMT conduit (recommended)
Electrical metallic tubing mounts to corrugated walls using strut channel (Unistrut) or standoff clamps. Durable, inspector-friendly, and allows future wire pulls without opening walls. Use ¾" EMT for most branch circuits, 1" for feeder runs carrying #6 AWG or larger. Follows the corrugation profile, which adds labor time for bends.
Best for: permanent installations, workshops, any job that needs to pass inspection
PVC conduit
Non-metallic conduit is lighter and easier to work with than EMT, and doesn't corrode. Requires additional bonding since it doesn't contribute to the grounding path. Slightly less durable than EMT in a work environment. Good choice for container homes where aesthetics matter and walls will be finished.
Best for: container homes, finished interiors, humid environments
MC cable (metal-clad)
Armored cable is faster to install than conduit and works well in finished container interiors. Cannot be used for exterior runs on metal structures per NEC. Requires anti-short bushings at every termination to protect wire insulation from the armor edges.
Best for: interior runs in finished walls, residential container builds
Surface raceway
Plastic channel that mounts flat against the wall and holds wiring inside a snap-on cover. Installs fastest and works in client-facing finished spaces. Cannot satisfy NEC requirements for exterior runs. Holds fewer conductors per channel than conduit. Easy to modify or add circuits later.
Best for: offices, retail spaces, situations where wiring may change frequently
Romex (NM cable) is not suitable for exposed container walls
Non-metallic sheathed cable (Romex) is standard in wood-frame residential construction but cannot be used exposed on metal surfaces per NEC Article 334. It can be used inside finished walls where it's protected, but any exposed runs on bare container walls must use conduit or MC cable.
Step 5 — Ground the container (critical)
Grounding a shipping container is the most important and most frequently botched part of container electrical work. A steel container is a large metal enclosure — if there's a fault in the electrical system and the container isn't properly grounded, the entire steel structure becomes energized. Anyone touching the container becomes the path to ground.
There are two grounding requirements for containers:
- Equipment grounding: The container's steel structure must be bonded to the electrical panel's grounding bus. This means a grounding conductor connecting the container body to the panel ground bar.
- Grounding electrode: One or two 8-foot copper-clad grounding rods driven into the earth at the container location, connected to the panel's grounding bus. NEC typically requires two rods unless the first measures 25 ohms or less to ground (have this tested).
Additionally, all metallic conduit runs must be bonded together and connected to the grounding system. With EMT conduit, the conduit itself serves as the equipment grounding conductor — but only if all connections are tight and continuous. A loose fitting breaks the grounding path.
Test your ground rod resistance
Have your electrician test the grounding rod resistance with a ground resistance meter. NEC requires 25 ohms or less — if your single rod doesn't achieve this, a second rod is required. In rocky or very dry soil, additional rods or a ground ring may be necessary.
What it costs to wire a shipping container
Costs vary significantly based on panel size, power source, and how finished the interior needs to be. These are US averages for a 20-foot container being converted to an office or workshop.
A 40-foot container runs roughly 40–60% more than a 20-foot container due to the additional conduit runs and circuit count. Container homes with full kitchen, bathroom, and HVAC wiring typically run $8,000–$15,000 for the electrical alone.
NEC code requirements for container electrical
Containers fall under standard NEC commercial and residential codes depending on their use. A few articles are particularly relevant:
| NEC Article | What it covers | Applies to containers |
|---|---|---|
| Article 250 | Grounding and bonding | Yes — critical for metal structure bonding |
| Article 334 | Non-metallic sheathed cable (Romex) | Restricted — cannot use exposed on metal |
| Article 358 | EMT conduit installation | Yes — governs EMT mounting and fittings |
| Article 406 | Receptacle requirements | Yes — GFCI requirements in wet locations |
| Article 590 | Temporary wiring | Yes — for jobsite/temporary container power |
Local jurisdictions often have amendments to NEC — always check with your local building department before starting. Some areas require conduit for all wiring regardless of wall cavity; others have specific requirements for accessory structures on residential lots.
Frequently asked questions
Can I wire a shipping container myself?
Only if you're a licensed electrician or working under licensed supervision. Most jurisdictions require permits and inspection for permanent electrical installations, and inspectors won't approve work done without a permit. The metal structure grounding requirements are also specific enough that DIY mistakes are genuinely dangerous — a missed bond on a steel container means the whole structure can become energized in a fault situation.
Do I need a permit to wire a shipping container?
Almost certainly yes for any permanent installation. Temporary power (a jobsite spider box or extension cord from a generator) may not require a permit, but any fixed wiring with a panel and circuits will. Contact your local building department — they'll tell you what's required for your specific use case and location.
How long does it take to wire a container?
A basic office or storage container with a sub-panel and 6–10 circuits takes an experienced electrician 2–3 days. A full container home with kitchen, bathrooms, HVAC, and complex lighting takes 5–10 days. Add permitting time — typically 1–3 weeks depending on your jurisdiction.
What size wire do I need?
For a 100A feeder from a main panel: #4 AWG copper or #2 AWG aluminum in conduit. For 20A branch circuits (standard outlets): #12 AWG. For 15A circuits (lighting): #14 AWG. For 240V appliances (mini-split, dryer): depends on the appliance — check the nameplate amperage and size accordingly. Your electrician will calculate the correct wire gauge for each circuit.
Looking to buy or rent a container for your project?
Shipped.com supplies containers across the US with delivery to your site. Compare prices, sizes, and delivery options before you buy.
Get container quotes →