Subpanel Installation Cost

National cost range

Low end

$900

Simple access, like-for-like

Typical

$1,800

What most jobs come in at

High end

$3,500

Upgrades, difficult access, code work

What you are actually paying for

Find the row that matches your situation. Quotes that differ wildly from each other usually differ in scope, not in price.

What moves the price

In descending order of impact. These are also the questions worth asking a contractor whose quote sits outside the range above.

1. 1

   Subpanel size and feeder

   A 60-amp subpanel needs 6 AWG copper feeder. A 100-amp subpanel needs 2 AWG copper or 1/0 aluminum. The feeder run length drives voltage drop and conductor cost.

2. 2

   Distance from main panel

   A subpanel in the garage on the other side of the same wall is cheapest. A detached garage 100 feet away needs a buried feeder in conduit at significant cost per foot.

3. 3

   Main panel capacity

   The subpanel load counts against the main service. A 200A service can support a 100A subpanel if the calculated load allows. A 100A service may not have room for a large sub.

4. 4

   Number of circuits needed

   A 6-space subpanel covers a small garage. A finished basement workshop may need a 20-space panel. Larger panels cost more but avoid a second subpanel later.

5. 5

   Detached structure bonding

   A subpanel in a detached garage requires its own grounding electrode (ground rod) and a 4-wire feeder. Bonding mistakes here are a common inspection failure.

Direct answer

Subpanel installation in 2026 typically costs $900 to $3,500, with national planning near $1,800 for a standard residential feed. A 60-amp subpanel in an attached garage with a short run often runs $900 to $1,600; 100-amp basement finish subpanel $1,200 to $2,200; detached garage with 75-foot trench $2,000 to $4,000; subpanel plus main upgrade to 200A $3,000 to $6,000. Feeder gauge—6 AWG copper for 60A, 2 AWG or 1/0 aluminum for 100A—and detached-structure grounding electrodes drive cost more than panel brand.

What each price band actually buys

Low end

60-amp panel through one wall from main, attached garage, grounding bonded to main system.

Typical

100-amp sub for basement or workshop, labeled circuits, permit, load calculation documented.

High end

Detached structure with underground feeder, ground rod, long voltage-drop run, or concurrent service upgrade.

Labor vs materials

Typical split for this job nationally: roughly 65% labor and 35% materials. Crew size is usually 1–2 licensed electricians, across one full day to two days.

What this price usually does not include

• Circuits homerun from sub to distant rooms beyond agreed count
• EV charger, hot tub, or generator interlock unless separate scope
• Trench landscaping restoration
• Main panel upgrade when service ampacity is insufficient
• Structural carpentry to mount panel board
• Future expansion circuits not in original contract

Hidden costs that show up on real jobs

Regional variation

Detached garage subs are systematically more expensive than through-the-wall attached installs. Inspectors in strict counties focus on bonding errors—hire licensed work. `/home/cost/subpanel-installation/[metro]` localized data helps when comparing trench allowances.

Code upgrades this job can trigger

• Proper feeder breaker sizing and conductor ampacity
• Separate grounds and neutrals bonded only at main unless revision rules apply
• Grounding electrode system for detached structures
• Working clearance and panel height
• Load calculation showing main service supports added sub capacity

Repair vs replace

Add a subpanel when the main is out of spaces but service ampacity supports the load—not as a substitute for a dangerous main panel. Replace a rusted or Federal Pacific sub with a new listed panel rather than adding circuits to obsolete busing. If tandem breakers are listed and load calc passes, they may avoid a sub on marginally full panels.

Timeline and visits

Attached short-run subs often finish in one day. Detached trench jobs may take two days plus inspection. Utility involvement is rare unless service upgrade is bundled.

Quote checklist — line items a fair bid should show

1. Subpanel ampacity and spaces
2. Feeder conductor size and length
3. Attached versus detached and grounding plan
4. Trench map and restoration
5. Permit and load calculation
6. Main breaker size feeding the sub
7. Labeling and initial circuit count
8. Warranty

Questions to ask before you sign

• Is my main service large enough for this sub per load calculation?
• For detached garage, will you install ground rod and 4-wire feeder?
• How many circuits are included in this sub install?
• What trench depth and conduit type will you use?
• Who handles inspection failures on bonding?
• Is main panel upgrade quoted separately if needed?

Quote red flags for this job

• 3-wire feeder to detached garage without ground rod plan
• Subpanel ampacity exceeds main service without upgrade discussion
• No permit on new feeder
• Bonding neutrals and grounds at sub against NEC for your configuration
• Feeder undersized for stated 100A sub
• Trench excluded on obvious detached run

Payment schedule norms

Typical: 25–33% deposit for materials, balance at inspection. Trench jobs may use midpoint draw when conduit is in place.

Can you do it yourself?

When this cannot wait

• Main panel completely full with no room for tandem breakers
• Finished basement or garage needing power but no available circuits
• Workshop equipment tripping breakers on shared general circuits

Common questions