What Size Electrical Panel Does My House Need?

Most Long Island homeowners do not think about their electrical panel until something forces the conversation. A home inspector flags it. A contractor says the service needs to be upgraded before a new appliance can be added. A neighbor mentions they just had an electrical panel upgrade done. However it comes up, the first question is usually the same: what size do I actually need? The answer depends on your home's square footage, how it is heated and cooled, which appliances you use, and whether you plan any additions or upgrades in the near future. This guide explains what the panel sizes mean, which homes typically need which service level, and why so many Long Island homes no longer have enough.

What an Electrical Panel Actually Does

Your electrical panel, sometimes called a breaker box or load center, is where power from the utility, PSEG Long Island for most of Nassau and Suffolk County, enters your home and is distributed to individual circuits. Each circuit breaker in the panel protects a specific circuit by tripping, or shutting off, when the current on that circuit exceeds the wiring's safe carrying capacity.

The overall size of the panel, expressed in amperes (amps), determines the total amount of electrical current your home can draw at any given time. A 100-amp panel can handle up to 100 amps of total current. A 200-amp panel doubles that capacity. When your home's demand exceeds the panel's capacity, breakers trip, circuits become unreliable, and, in some cases, the wiring can increase the risk of overheating and potential fire hazards.

The Three Common Residential Panel Sizes

100-Amp Service

A 100-amp panel was the residential standard through most of the mid-20th century. Homes built before roughly 1970 frequently still have this service level, and it was considered more than adequate for the electrical loads of that era. A 1,000-square-foot home with gas heat, a gas stove, no central air conditioning, and modest appliances could function on 100 amps.

Today, 100-amp service is generally considered the minimum acceptable for a small home, and for most occupied Long Island homes, it often falls short. A central air conditioner can draw between 15 and 50 amps, depending on the system size. Add a dishwasher, a refrigerator, a washer and dryer, lighting, several device chargers, and a 100-amp panel, and it can find itself at or near its limit during normal daily use before anything unusual is added.

200-Amp Service

200-amp service became the residential standard in new construction starting in the 1970s and remains the most common upgrade target for older Long Island homes today. It provides enough capacity for a typical single-family home with central air conditioning, electric appliances, a home office, and normal modern usage.

For most homeowners making a single upgrade, 200 amps is the right answer. It comfortably handles everyday demand and leaves room for additions such as a hot tub, a finished basement, or additional HVAC equipment.

400-Amp Service

400-amp service is typically installed in larger homes, homes with significant electrical heating loads, or properties where multiple high-draw systems run simultaneously. It may be the right choice if any of the following apply:

• An EV charger running alongside central air conditioning and a heat pump

• A home with a dedicated workshop, studio, or outbuilding that has its own subpanel

• A home addition that substantially increases square footage and electrical load

• Properties planning full electrification, replacing gas heating and appliances with electric alternatives

If full electrification is your long-term direction, installing 400-amp service now costs less than upgrading twice.

Why Long Island Homes Are So Often Undersized

Suffolk County has a large stock of homes built between the 1940s and 1970s. The post-war building boom that created communities like Levittown and spread across Nassau and into Suffolk produced thousands of homes wired for the technology of that era. Many of those homes still have 60-amp or 100-amp service, some with original wiring that has never been touched.

The electrical demand in those same homes has increased dramatically over the decades. Central air conditioning arrived. Electric dryers replaced clotheslines. Home offices drew consistent power loads. Smart TVs, streaming devices, gaming systems, and multiple phone chargers added incremental but steady demand. Now that EV chargers and heat pumps are entering more households, the gap between what older panels were designed to deliver and what modern homes actually require has become significant.

Homeowners often discover this gap only when something goes wrong. Frequent breaker trips, lights that dim when the air conditioner kicks on, or an electrician flagging the panel during a renovation are common triggers. In some cases, homeowners learn at closing that a buyer's inspector has noted the undersized service as a condition of the sale.

What Determines the Right Panel Size for Your Home

A licensed electrician determines the correct panel size through a load calculation, which accounts for the actual electrical demand of your home's systems and appliances. The National Electrical Code (NEC) provides the standard methodology for these calculations. Several factors drive the result:

• Heating and cooling systems. Electric baseboard heat, heat pumps, and central air conditioning units are among the highest-draw systems in any home.

• Electric vs. gas appliances. An all-electric kitchen draws considerably more than a gas kitchen. The same is true for hot water heaters.

• EV charging. A Level 2 EV charger commonly requires a dedicated 40- to 50-amp circuit. If you plan to charge at home, this needs to be factored in.

• Square footage and number of circuits. Larger homes require more circuits for lighting, outlets, and dedicated appliance loads.

• Planned additions or renovations. If you are finishing a basement, adding a room, or converting an attached garage, those loads need to be accounted for before the panel is sized.

Signs Your Current Panel Is Not Keeping Up

You do not always need an inspector to tell you there is a problem. Some signs are obvious in daily use:

• Breakers trip regularly, especially when multiple appliances run at the same time

• Lights dim or flicker when large appliances cycle on

• You have added appliances or a room, and the circuits feel strained

• An electrician or home inspector has flagged the panel as undersized or outdated

• You are planning to add an EV charger and have been told the current service cannot support it

A Note on 60-Amp Panels

Some older Long Island homes still have 60-amp service, particularly smaller cape-style homes and cottages built in the 1940s and 1950s. A 60-amp panel is generally no longer adequate for a modern occupied home and should be evaluated for an upgrade. At that service level, running a window air conditioner, a microwave, and a clothes dryer simultaneously can trip the main breaker. Most licensed electricians will not add circuits to a 60-amp panel in a home with modern occupancy demands, and many homeowners' insurance carriers have questions about properties still on 60-amp service.

Panel Upgrade vs. Service Upgrade: Understanding the Difference

These two terms come up together often but refer to different things. A panel upgrade replaces the breaker box inside your home with a larger or newer unit. A service upgrade increases the size of the electrical service entering your home from the utility, typically requiring coordination with PSEG Long Island and may involve new metering equipment.

If you are upgrading from 100-amp to 200-amp service, both pieces are usually involved. The work requires a permit, an inspection, and scheduling with the utility. A licensed electrician handles the electrical side of this process. The utility handles its side, including meter upgrades and any work on the service entrance.

Permits and Inspections on Long Island

Panel upgrades in Nassau and Suffolk County require an electrical permit. The permit is pulled by the licensed electrician performing the work, not the homeowner. After the work is complete, it must be inspected by the local authority having jurisdiction before PSEG will reconnect service.

Skipping the permit process creates real problems. Unpermitted electrical work can void homeowners' insurance coverage, create issues at the time of sale, and leave you with no recourse if something goes wrong with the installation. Any electrician who suggests skipping the permit is worth walking away from.

What to Expect from the Process

A standard 200-amp panel upgrade on Long Island is typically completed in a single day once the permit and scheduling are in place. The electrician pulls the permit from the local municipality, which in most Suffolk County towns takes a few business days to a week, then coordinates a temporary power shutoff with PSEG. The old panel is removed, the new panel is installed, circuits are reconnected, and the work is inspected. Once it passes inspection, PSEG restores service. Most homeowners are without power for only a portion of the day. PSEG scheduling for the shutoff and reconnect is usually the longest variable in the timeline, and your electrician should coordinate that directly so there are no surprises.

More complex upgrades, such as a move from 100-amp to 400-amp service or relocating the panel or upgrading wiring in older homes, will take longer and require more coordination. The only way to know for certain is a site assessment.

Get the Right Answer for Your Home

If you are not sure what size panel your home currently has or whether it is adequate, the best first step is a conversation with a licensed electrician who knows Long Island. Ohmega Electric handles electrical panel upgrades across Nassau and Suffolk County with more than 30 years of experience in residential and commercial work. As a Service-Disabled Veteran-Owned Small Business, we give you a straight answer on what your home actually needs, and we do the work properly.

Call 631-729-6204 or visit our contact page to schedule an assessment.