Electrical Sub Panel Installation in Los Angeles

Adding a home office, an EV charger, a backyard workshop, or an ADU often reveals the same problem: your existing electrical panel is out of open breaker slots, or simply out of capacity. A sub panel is the clean, code-compliant way to add circuits without overhauling your main service. Here is what Los Angeles homeowners should know before installing one.

What Is an Electrical Sub Panel?

A sub panel (also spelled subpanel, or called a satellite panel) is a smaller breaker box fed by your main electrical panel. It distributes power to a specific area or group of circuits, such as a detached garage, a converted ADU, a kitchen remodel, or a bank of high-draw appliances. Your main panel still protects the whole home; the sub panel simply adds breaker space and places those circuits closer to where they are used, which shortens wire runs and reduces voltage drop.

Signs You Need a Sub Panel Installed

Consider an electrical sub panel installation when any of these apply:

• Your main panel is full, with every breaker slot occupied and new circuits still needed.
• You are finishing a garage, basement, or workshop that requires several dedicated circuits.
• You are building an ADU or garage conversion that needs its own distribution point.
• You are adding high-demand equipment such as an EV charger, hot tub, mini-split, or welder.
• The new circuits are far from the main panel, and a local sub panel saves on long, expensive wire runs.

Where LA Homeowners Add a Sub Panel

In Southern California, the most common request we see is a garage sub panel installation — a detached or attached garage becoming a workshop, home gym, or EV-charging spot. A 100 amp sub panel is a popular size here because it comfortably handles a Level 2 EV charger plus lighting, outlets, and power tools. ADUs and garage conversions almost always need their own sub panel so the living space has organized, independently protected circuits and its own point of shutoff.

Sub Panel Installation Cost in Los Angeles

Sub panel installation cost in Los Angeles varies with amperage, the distance from the main panel, and whether trenching or new conduit is required. As a general guide (always verify with an on-site estimate):

• Small 60–100 amp sub panel, short interior run: roughly $1,000–$2,000.
• 100–125 amp sub panel with a moderate run through walls or attic: roughly $1,500–$3,500.
• Detached structure (garage or ADU) with trenching and buried conduit: roughly $2,500–$6,000+.
• If your main panel is also full or undersized, a main panel upgrade may be required first, which is a separate cost.

Prices vary by site conditions and current material costs, so treat these as ballpark ranges, not quotes. If your main service can’t support the added load, start with an electrical panel upgrade before adding the sub panel.

Permits and Code in Los Angeles

Sub panel work requires a permit almost everywhere in LA County. A licensed electrician pulls the permit, sizes the feeder correctly, and — importantly — keeps the neutral and ground separated in the sub panel (they are bonded only at the main). That single detail is one of the most common DIY mistakes and a frequent inspection failure. Correct grounding, properly sized feeder wiring, and an appropriate feeder breaker at the main panel are all checked at inspection. If the sub panel is feeding an EV charger, the circuit must also meet the current EV-charging requirements.

Frequently Asked Questions

How much does sub panel installation cost in Los Angeles?

Most jobs land between roughly $1,000 and $6,000 depending on amperage, distance, and whether trenching is needed. A simple interior 100 amp sub panel is on the lower end; a detached garage or ADU with buried conduit is higher. An on-site estimate gives you an accurate figure.

Do I need a permit to install a sub panel?

Yes. Sub panel installation is permitted electrical work in the City and County of Los Angeles. A licensed C-10 electrician can pull the permit and schedule the required inspection so the work is documented and safe.

What size sub panel do I need?

It depends on the loads. A 60 amp sub panel suits a small workshop or a handful of circuits, while a 100 amp sub panel is the go-to for garages, ADUs, and EV charging. An electrician runs a load calculation to size both the sub panel and its feeder correctly.

Can I add a sub panel if my main panel is full?

Sometimes. If your main panel still has capacity, a sub panel adds usable breaker space. If the main is undersized or maxed out, you may need a panel upgrade first. A load calculation tells you which path applies to your home.

How long does a sub panel installation take?

A straightforward interior sub panel is often a one-day job. Detached structures that need trenching, conduit, and coordination with the inspector can take two or more days.

911 Construction & Electric Inc. is a licensed, bonded, and insured C-10 electrical contractor (CA Lic. #1027421) serving Los Angeles, Pasadena, Burbank, Glendale, and nearby cities. Whether you need a garage sub panel, an ADU feeder, or a full panel upgrade, our EVITP-certified team sizes it right and handles the permit. Call 747-255-8595 or request your free estimate today.