On this page 4 sections
Garage subpanel: attached or detached decides the job
Powering a garage is really two different jobs, and which one you have is the first thing to settle. A garage under the same roof is a straightforward subpanel. A detached garage is its own structure in the eyes of the code, and that changes what it needs and what it costs.
Attached garage
Part of the main building. The feeder runs from the main panel to the garage wall, wired like any in-building subpanel — four-wire feeder, isolated neutral, no separate grounding electrode of its own.
Detached garage
A separate structure across the yard. It needs its own grounding electrode at the building, a four-wire feeder, and its own disconnect — which is why a detached garage is more work than a subpanel on the other side of a shared wall.
Tell us which one it is on the call, and the rest of the conversation is honest about what it takes.
A detached garage subpanel needs its own ground, feeder, and disconnect
The extra requirements for a detached building are not optional add-ons — they are what makes the installation safe and what the inspector checks. This is where the cost difference comes from.
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Its own grounding electrode
A detached structure gets its own grounding electrode — a ground rod or rods driven at the building — so it is grounded locally, not only back at the house (2025 California Electrical Code / NEC 2023, 250.32). That earth connection is grounding, and it is part of this job, not a later extra.
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A four-wire feeder
Two hots, a neutral, and a separate equipment ground run out to the garage, with the neutral and ground kept separate at the subpanel — the same separation any subpanel needs, and the thing a shortcut install skips.
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A disconnect at the building
A separate structure needs a way to shut its power off at the structure itself, under the rules for feeders to another building (NEC Article 225). That is not the dwelling emergency disconnect — it is the shutoff at the garage.
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A buried or overhead run
The feeder reaches a detached garage underground or overhead. Burial depth is set by the local authority and the soil, so it is confirmed for your address rather than quoted from a table.
Garage subpanel for a charger, a shop, or a house service that is already close
A garage subpanel is rarely wanted for its own sake — something in the garage needs the power. What that something is can point at a neighboring job.
An EV charger in the garage
A charger is a common reason to bring real power out, but the charger circuit itself — sizing, the connector, the route to the car — is its own job. The subpanel gets power to the garage; the EV charger installation covers the circuit.
A workshop or heavy tools
Saws, compressors, welders, and their dust collection want their own circuits close to the bench. A garage subpanel gives them a local group of circuits instead of long runs back to the house.
The house service is already tight
A feeder to the garage is a new load on the house. Whether the service can carry a charger, a workshop, or both is the panel upgrade question — the answer can be no. If that need is already established, the increase is a 200-amp service upgrade, not a bigger garage feeder.
An attached garage instead
If the garage is under the main roof, you do not need the detached-structure hardware at all — that is a plain subpanel installation, and the cheaper of the two.
What changes the cost of a garage subpanel
A garage subpanel is priced from the run and the structure, not from the box. These are what move the scope once we see attached or detached, and how the feeder gets there.
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Attached or detached
The single biggest factor. A detached structure adds a grounding electrode, a disconnect, and a longer run; an attached garage needs none of that, and is priced like any in-building subpanel.
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How the feeder gets there
An overhead span and an underground trench across a yard or driveway are different amounts of work to reach the same garage.
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Feeder size
What the garage will carry — a charger, a workshop, or just lights and outlets — sets the feeder and the subpanel rating. A charger on a tight house service is the upgrade conversation first.
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Permit and inspection
A feeder to a garage is permitted and inspected, and the authority for the address is confirmed before the work is scheduled.
Not sure this is the right job?
Tell us what you are seeing — what is tripping, what changed, or what you are planning — and we will tell you what the work actually is before anyone drives out.
Garage subpanel questions
Why does a detached garage cost more than an indoor subpanel?
Because a separate structure needs its own grounding electrode, its own disconnect, and a feeder run out to it — usually buried or overhead. An attached garage skips all of that and is wired like any in-building subpanel.
How deep does the feeder have to be buried?
That depends on the wiring method, the local authority, and the soil, so we confirm the depth for your address rather than quote a single number. It is set before the trench is dug, not guessed.
Does my garage need its own ground rod?
A detached one does — a separate structure is grounded locally as well as through the feeder. That earth connection is grounding. An attached garage does not need its own rod, because it is part of the building the main panel already grounds.
Can one subpanel feed an EV charger and the rest of the garage?
Usually yes — that is a good reason to bring a properly sized subpanel out rather than a single circuit. The charger circuit is still sized and run as its own job off the subpanel; that is EV charger installation.
Do I need 200 amps to power the garage?
Not automatically. Whether the house service can carry the garage feeder — and a charger if one is coming — is the panel upgrade question. This job is the feeder to the garage after that answer is known.
Should I run a subpanel to my garage?
A detached garage or a shop with several large tools usually wants its own disconnect and grounding electrode. We design that from the main.
What size subpanel do I need for my garage?
Size follows the tools and the lights you will install, plus the current unused capacity at main panel for your property .
Can you run a 100 amp subpanel off of a 100 amp service?
Only if the load calculation still fits. A 100 amp subpanel on a 100 amp main leaves no spare at the main, which can become an issue if you put a lot of equipment on the subpanel. Tell us what you're planning and we'll do a load calculation and help you understand if a sub-panel is a good solution.
Still not sure it is the right job? Call (279) 972-9272 — available 24 hours.Want the detail? ADU electrical
Helpful guides
ADU electrical
An ADU adds a dwelling’s worth of load. The right design is a load calculation — not an automatic 200-amp service or a second meter.
Read guideEV-ready garage electrical
EV charging is one garage load among others. Plan the circuit, panel capacity, a second EV, workshop loads, and a subpanel before the garage is finished.
Read guideWorkshop 240V tools
A welder, a compressor, and a dust collector are three nameplates — not one shop breaker, not a leftover 14-50, and not an EV charger. Call (279) 972-9272.
Read guide
Serving 19 communities across the Sacramento area
Litel Electric serves homeowners throughout all 19 communities in our service area — from Davis and Woodland to Roseville, Folsom, and Elk Grove.
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