Question 1

Why do I need a subpanel instead of just more breakers?

Accepted Answer

When the main panel is physically full or the service capacity is tight, a subpanel adds circuit space and often reduces voltage drop to distant loads like a detached garage.

Question 2

What size subpanel do I need for a detached garage?

Accepted Answer

Most residential garages run well on a 60A subpanel; workshops with welders, air compressors, or an EV charger typically need 100A.

Question 3

Does a detached-building subpanel need its own ground rods?

Accepted Answer

Yes — NEC 250.32 requires a grounding electrode at any separate structure. We drive two 8-foot rods and bond them properly.

Question 4

Can I run a subpanel feeder underground?

Accepted Answer

Yes. We use direct-burial USE cable or PVC conduit with THWN conductors 18" deep (24" without conduit) per NEC.

Question 5

Should the subpanel neutral be bonded?

Accepted Answer

No — only the main panel bonds neutral to ground. A subpanel must have an isolated (floating) neutral bar or the ground carries return current.

Question 6

How much does a subpanel cost to install?

Accepted Answer

Interior 100A subpanels typically run $1,200–$2,000. Detached garage subpanels with trenching run $2,500–$5,000 depending on distance and surface.

Question 7

Can a subpanel be fed from another subpanel?

Accepted Answer

Yes, as long as the upstream panel and feeder are sized for the total load. We commonly stack a garage subpanel off a basement subpanel.

Question 8

Do I need a permit for a subpanel?

Accepted Answer

Yes in every DMV jurisdiction. We pull it and schedule the inspection.

Question 9

What brand of subpanel do you install?

Accepted Answer

Square D QO or Homeline, Eaton BR or CH, and Siemens are our standards. We match the main panel where possible for consistent breaker stock.

Question 10

How long does a subpanel install take?

Accepted Answer

Interior subpanels are typically one day. Detached buildings add a day for trenching and inspection scheduling.

Subpanel Installation

What's included

Our process