200 Amp vs 400 Amp Service: Which Does Your Home Need?

Most homes need 200 amp service, not 400. A 200 amp service handles the typical house, including central heat pump or AC, an electric range and dryer, and one Level 2 EV charger. A 400 amp service makes sense for very large or all-electric homes, or for properties with several heavy loads such as two EV chargers, a pool, a spa and a workshop. The deciding factor is not square footage alone. It is a load calculation done for your specific house.

Below we cover what the two sizes actually deliver, what a 400 amp upgrade costs, how it is built, what the utility has to say about it in our Myrtle Beach area, and cheaper options that often solve the same problem.

Guardianhrsc

Know What Service Your Home Needs

Guardian Electrical Contractors provides panel upgrades and troubleshooting in Myrtle Beach, helping homeowners assess electrical needs for their property.

Explore electrical services

TL;DR

200 amp service supplies about 48,000 watts, and 400 amp service about 96,000 watts. Most homes up to roughly 3,000 to 3,500 square feet fit comfortably in the 200 amp range.
A 400 amp upgrade commonly runs $3,500 to $12,000, versus $1,500 to $3,850 for a 100 to 200 amp upgrade. Utility work can add cost and delay.
If you are only short on breaker slots, a subpanel or load management device may solve the problem for far less than a new service.
A formal load calculation, not a rule of thumb, tells you which size you need. Service entrance work must be done by a licensed electrician.

What the numbers on the label mean
200 amp vs 400 amp at a glance
When 200 amps is enough
When 400 amps earns its cost
What a 400 amp service upgrade costs
How a 400 amp service is actually built
What the utility requires in Myrtle Beach
Do you actually need more capacity, or more room?
EV chargers: check load management first
How to decide: a practical sequence
Our perspective
Talk to us about your service
FAQ
Sources

What the numbers on the label mean

Service amperage is the maximum current your home can draw from the utility at one time. At 240 volts, a 200A service provides 48,000 watts and a 400A service 96,000 watts. That is the whole-house ceiling, shared by everything running at the same moment: HVAC, water heater, oven, dryer, car charger, lighting and outlets.

Nobody runs everything at once, which is why a house with 300 amps worth of nameplate appliances can still live happily on 200 amps. The code accounts for this with demand factors inside the load calculation. Electricians point out that amperage is set by that formal calculation under NEC Article 220, which weighs lighting, appliances and heating and cooling loads, rather than by house size alone.

Two more terms are worth knowing:

Continuous rating. A 400A meter base is typically rated for 320A of continuous load, according to the same sizing guide. EV chargers count as continuous loads, so this matters.
Panel versus service. The service is the whole path from the utility transformer to your first main breaker. The panel is one piece of it. Upgrading the service means conductors, meter base, grounding and often the utility connection, not just a new box.

200 amp vs 400 amp at a glance

	200 amp service	400 amp service
Capacity at 240V	48,000 watts	96,000 watts
Typical home	Up to about 3,000 to 3,500 sq ft	Often 5,000+ sq ft or heavy all-electric loads
EV charging	Comfortable with one Level 2 charger	Suits two chargers at 48A each
Typical cost	100A to 200A upgrade: $1,500 to $3,850	$3,500 to $12,000
Typical equipment	One 200A panel	400A meter base feeding two 200A panels
Utility involvement	Usually routine	Often needs coordination, sometimes a larger transformer

Capacity and sizing figures come from the sizing guide, and cost ranges from 2026 cost data. Your own price depends on your property, which is why we quote after seeing the site.

When 200 amps is enough

A 200A service is the modern residential standard. According to the sizing guide, it easily handles a central heat pump, electric dryer, range and a single Level 2 EV charger. Another contractor guide describes the same typical home: gas or standard heating and cooling, electric range, dryer and water heater, one Level 2 charger and modest exterior loads.

In practice, 200 amps is plenty for a typical Grand Strand house when:

The home is under about 3,500 square feet.
You have one central HVAC system, not several large ones.
You plan one EV charger, or two with a load management device.
Pool and spa loads are modest.
Nothing like electric resistance heating is in the plan.

If your house is older and still on 100A, the jump to 200A is the routine step. Our 200-amp service upgrades cover exactly that, and it is the right answer far more often than a jump straight to 400.

When 400 amps earns its cost

The case for 400A is real, just narrower. The sizing guide recommends it for homes over 5,000 square feet or those with several high-demand systems: dual EV chargers at 48A each, whole-home battery backup, electric resistance heat, or large pool and spa installations.

Typical triggers:

Large custom or all-electric homes. Multiple HVAC zones, electric cooking, heat pump water heaters and a big footprint add up quickly.
Two or more fast EV chargers. Two 48A chargers draw continuous current that, with the rest of a large house, can crowd a 200A service.
Outbuildings and accessory units. A barn, guest house, detached garage or workshop with its own loads is a common reason owners plan a second panel location.
Pools, spas and outdoor kitchens. A heated pool plus a spa is a heavy block of load. A spa heater alone can be a significant continuous draw, so list every piece of equipment you own or plan to buy.
Future-proofing a new build. Running heavier conductors while walls and trenches are open costs less than doing it later.

Be honest about the last one. The Schneider Electric guide notes that 400A is often a luxury or future-proofing choice for custom, all-electric homes, with limited return on investment for many households. It also warns that utility-side work, often outside the contractor's control, can bring unpredictable delays and costs.

What a 400 amp service upgrade costs

According to 2026 cost data, a 400A upgrade typically costs between $3,500 and $12,000, depending on utility coordination, the distance to the main panel and local labor rates. Trenching, a new service mast and concrete repair often push a job toward the top of that range. A regional contractor price table lists a narrower $3,500 to $6,000 for a 400A panel upgrade, which shows how much the scope assumptions matter.

What a 400 amp service upgrade costs — overview diagram

For comparison, the same cost data puts a 100A to 200A upgrade at $1,500 to $3,850.

What moves the price:

Overhead or underground service. Underground runs mean trenching and restoration.
Distance from meter to panel. Longer runs need more of the heavy conductor.
Conductor size. A 400A service uses parallel sets of conductors, often 3/0 copper or 350 kcmil aluminum, far heavier than 200A wire.
Grounding and bonding. The grounding system may need expanding to meet current code.
Utility work. The existing transformer may need upsizing.
Permits and inspection. Required for service work.

If you are comparing quotes, make sure each one states the same scope: meter base, number of panels, conductors, grounding, permit and who handles the utility paperwork. For a broader look at pricing, see our breakdown of electrical panel upgrade costs.

How a 400 amp service is actually built

Many people picture one giant 400A panel. That is rare. A 400A service is most commonly built as a 400A (320A continuous) meter base feeding two separate 200A panels. That setup costs less and lets you place one panel near the main house loads and another near a workshop, pool equipment or EV chargers, which splits the load and shortens branch circuit runs.

One meter feeding two separate 200A panels

So "400 amp service" often means two 200A panels under one meter. That is a useful fact when you are planning where heavy loads will live. A garage-side panel for chargers and tools, for example, keeps big wire runs short. Our 400-amp electrical service upgrades page covers how we scope this kind of project.

What the utility requires in Myrtle Beach

The meter and service connection are the utility's territory, and in Myrtle Beach that is Duke Energy. Its service requirements manual says residential services up to 200A generally use self-contained, 200A-rated meter sockets. For 201A up to 400A, the standard requirement is a self-contained meter socket rated 320A continuous. Demand beyond that, or higher voltages, often calls for instrument transformer (CT) metering, which needs more coordination and specialized equipment.

The manual also advises consulting a local utility representative on load sheet requirements before you plan an upgrade. We agree: call before you buy equipment, because the meter socket type, service location and transformer capacity all affect scope and timeline. Requirements are revised periodically, so check the current edition rather than relying on an old printout.

Do you actually need more capacity, or more room?

This is the most overlooked question. Experts say that many perceived capacity problems are really circuit space problems. If you are only out of breaker slots but total capacity is fine, a subpanel can often fix it much more affordably than a full 400A service upgrade.

Signs you have a space problem, not a capacity problem:

The panel is physically full, with tandem breakers doubled up.
Lights do not dim and breakers do not trip when big loads run together.
You want to add a garage, workshop or addition, but the calculated load is still well under 200A.

In that case a subpanel installation gives you slots exactly where you need them. If the panel itself is old or damaged, panel replacement may be the right fix. Neither requires utility upgrades.

EV chargers: check load management first

EV charging is the reason many homeowners ask about 400A. Before assuming you need it, look at load management. Smart load management devices monitor total service current and throttle charging when other heavy loads run, often keeping a home within a standard 200A service and saving thousands in upgrade costs.

EV chargers are continuous loads, so the wiring and breaker are sized with a 125% factor. We walk through the math in our EV charger load calculation guide, and our Level 2 charger wiring guide covers the 32A to 40A and 48A to 60A circuits. As an example of the math: a 48A charger is a continuous load, so the circuit is sized for 60A. Two of them add 120A of circuit capacity before the rest of the house is counted, which is where 400A starts to look attractive for big homes without load management.

The U.S. Department of Energy's Alternative Fuels Data Center is a good neutral reference on Level 1 and Level 2 home charging.

How to decide: a practical sequence

List what you have and what you will add. HVAC, water heater, range, dryer, pool, spa, EV chargers, workshop, generator, battery.
Get a load calculation. This is the NEC Article 220 method, and it is the only reliable basis for sizing. The code's optional method for single-family dwellings is a streamlined version, but your electrician chooses which applies.
Ask whether load management or a subpanel solves it. Cheaper options come first.
Confirm utility requirements. Call Duke Energy about meter type and transformer capacity.
Price the scope, not just the amperage. Compare conductors, grounding, permits and utility coordination across quotes.
Decide on the future. If a second EV, a pool or an ADU is likely within a few years, build the capacity now when it is cheaper.

Our perspective

We see two mistakes on service upgrades. The first is under-sizing: a homeowner buys the cheapest fix and finds themselves redoing the work when the pool or second EV arrives. The second is over-sizing: paying for 400 amps, heavy conductors and utility work for a house that a 200A service with a subpanel would serve for decades.

Our approach is to start with a conversation. We ask what you own, what you plan to add and how you live in the house. We encourage you to send photos of your meter, panel and the spaces where new loads will go. Photos let us spot things like a full panel, an older meter base or a long run to the garage before anyone drives out, and they make the estimate more accurate.

Then we do the load calculation and lay out the options plainly: sometimes that is 400A, often it is 200A plus a subpanel or a load management device. We would rather tell you that you do not need the bigger service than sell you capacity you will never use. Service entrance equipment carries high current and is dangerous, so this is not DIY work. It needs a licensed professional, grounding and bonding to current code, and an inspection.

— Logan

Talk to us about your service

Guardian Electrical Contractors serves homes and businesses in Myrtle Beach, South Carolina. We offer free estimates and detailed consultations, including planning from photos you send. Whether you are sizing a new build, adding chargers or fixing a crowded panel, see our electrical panel and service upgrades or all services and tell us what you are planning. For a business property, our commercial panel upgrades page is the place to start.

FAQ

How many amps does a house need?

Most modern single-family homes are served by 200 amps. Older or smaller homes sometimes run on 100A, but that leaves little room for EV charging or electric heating. The right number comes from a load calculation of your actual appliances and equipment.

Can a 200 amp service run two EV chargers?

Often yes, with load management. These devices watch total current and slow charging when other heavy loads are running. Without them, two 48A chargers in a large, electrically heavy home may push you toward 400A, so have the load calculated first.

How much does 400 amp service cost?

Recent data puts a 400A upgrade at $3,500 to $12,000, depending on trenching, distance, utility work and labor rates. A 100A to 200A upgrade is far cheaper. We price each job after reviewing your site and photos.

Do I need a bigger service if I only run out of breaker spaces?

Usually not. Running out of slots is a space issue, and a subpanel can often fix it at much lower cost than a new service. A load calculation confirms whether total capacity is still sufficient.

Is a 400 amp service one big panel?

Typically not. It is most often a 400A meter base feeding two 200A panels, which can be placed near different loads such as the house, a workshop or pool equipment.