Can You Run 400 Amp Service With 2 200 Amp Panels?

Nowadays, people install higher amp services due to the increased use of electrical devices. We see 400 amp services more in residential properties across the US. Many house owners wonder if they can use 2 200 amp panels for a 400 amp service. 

The NEC does not deny using two 200 amp panels to run a 400 amp service. It depends on whether you can have a sub-panel or include two separate panels. But the maximum load on each panel should be below 200 amps. You can contact your local inspection department for the local codes. 

However, some experts don’t recommend two different panels due to high installation costs. This guide will explain both installation processes, their pros and cons, the cost, and other considerations. 

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Is it possible to run a 400 amp service with 2 200 amp panels?

In today’s world, there has been an increase in the usage of electrical appliances. 

So, people have started upgrading their service to higher amps, like 200 or 400 amps.

You can run a 400 amp service with 2 200 amp main disconnect panels. 

If you add a new branch circuit in your house, adding a new main panel will be an option. 

The case may be building a garage or workshop. 

Each panel will need a power line from the electrical meter base to the main panel. 

Sometimes, the local code will need the meter base to have a 2-lug design for such installation. 

A 2-lug meter base will have two neutral and two hot connections on the service side. 

Such a setting will have 2 separate power lines to attach to the meter base and comply with the electrical codes.

Pros and cons of installing two 200 amp main disconnect panels

Installing a main disconnect on each panel will be logical and more efficient, especially if the second main panel is in a separate location. 

Large houses will have a separate pool area, workshop, art studio, or other equipment structure. 

Sometimes, house owners will have an outhouse or a rental unit adjacent to their house. 

Installing two main 200 amp main panels will cost huge. 

Disconnect panels are more expensive than sub-panels. 

So, running two of them will result in a very high cost. 

Sometimes, you will even receive problems with your region’s building department and electrical codes. 

The local electrical codes will not permit you to run two main panels in one structure. 

Instead, the contractors will recommend you have only one main disconnect panel to protect your house’s electrical circuits. 

Even if the electrical codes approve your request, the building inspection department will demand high expenses for installing two main disconnect panels.  

Is there any alternative?

Since installing two main disconnect panels is quite expensive, you can use a 200 amp sub-panel if you have a 200 amp panel. 

A 200 amp sub-panel with a 200 amp disconnect also means running a 400 amp with 2 200 amp panels. 

Besides, the installation charge will be less for this option.

Installing two panels is very expensive. So, some contractors or builders recommend installing one panel. 

If you have a 200 amp main panel, you can install a 200 amp sub-panel instead of two main disconnect panels. 

Generally, we install a sub-panel when the main panel can no longer handle the circuit breakers.  

Numerous people install a sub-panel for safety purposes in places where they can conveniently access the main panel, for instance, upstairs or in a woodshop. 

The main disconnect switch is the main difference between the main service panel and the sub-panel. 

The National Electric Code, or NEC, claims every electrical installation must have a main disconnect switch or breaker. 

The main breaker is located inside the main service panel. 

It allows the electrical service to quickly and safely get disconnected from the other branch circuits in the house. 

The sub-panel will be close to the main entrance panel or places like a detached garage, workshop, or other utility areas. 

The power feeding the sub-panel will be taken from the main service panel so that the main disconnect breaker can protect both the main and the sub-panels. 

Considerations while installing a sub-panel 

While installing a 400 amp main panel with a sub-panel, you need to install a heavy and thick wire between the main and sub-panels. 

In some circumstances, you might use the same wire size in bringing the electrical service from the meter to the main service. 

Based on the installation, it will add extra cost for both the items and labor costs. 

You can install a sub-panel in a different location or separate location of your house, like a detached garage, workshop, or second-story rental building. 

The cost of using copper wires will be huge when the branch circuit distances are very long. 

Before you decide to install a 200 amp main panel and a 200 amp sub-panel, check with the local electrical codes of your region. 

If you are worried because it is only a 200 amp sub-panel, know that a 200 amp sub-panel can feed around 3 sub-panels. 

Some local codes will have extra needs or do not permit this installation where 400 amp is used in a residential area. 

Connecting process of the sub-panel

The first 200 amp panel should be at the main breaker box and load center. 

The second panel should feed the house, and you need to connect the sub-panel to the main panel. 

Take a 3-wire feeder cable with 3 insulated conductors and a bare copper conductor. 

Run the cable to the sub-panel from the main panel with the help of an electrician. 

The cable should be of the correct size to meet the requirements of the sub-panel amp. 

Get a #2/0 AWG copper wire or #4/0 AWG aluminum or copper-clad wire. 

For underground services, get 1.5 inches of PVC conduit Schedule 40 or 80. 

You may also need a 250 kcmil copper wire, based on the voltage. 

The feeder cable should have two hot wires, one neutral wire, and a bare ground wire. 

Connect the wires to the lugs on each hot bus bar in the sub-panel. The lugs act as a 400 amp meter base with lugs. 

Before connecting the neutral and ground wires to their bus bars in the main panel, attach them to the circuit breaker and link the hot feeder wires. 

Connect the main service panel feeder breaker to the open double slot. 

Both panels will need a ground wire. 

According to the electric code, a zero copper ground is stranded, shielded, and legit. 

Bring the 1-0 oversized wire for the 400 amp service into one 200 amp panel. 

Take the ground wire and bring it to the other panel.

If you hesitate to connect the panels, hire a professional to wire the sub-panels. 

Cost considerations 

The cost of installation is one of the major factors. 

Based on the installation cost, many people must decide between installing two 200 amp main disconnect panels or a 200 amp sub-panel. 

Besides, a lot of factors will affect the cost of the installation.

For example, the price of copper wires, breakers, and panel assemblies keeps fluctuating. 

The labor cost will differ based on the living region. It is extremely high in urban areas. 

Here is a small guide list about the cost of the installation:

400 amp service panel200 amp main disconnect panel with a sub-panelTwo 200 amp main disconnect panels
Service panel price $1,300$300$450
Circuit breaker price (16 branch circuits)$96$96$96
Branch circuit wiring (Avg. residential new construction runs)$9.73 per foot$9.73 per foot$9.73 per foot
Service line price (Underground 400 amp 240V service line)$20 to $40 per linear foot$20 to $40 per linear foot$20 to $40 per linear foot

The above costs are average and will differ based on your area. 

If you live in an urban area, the price may be higher than these mentioned prices. 

Sometimes, there will be additional costs with these expenses. 

Ask your local utility companies for the price of both installations. 

What does the National Electric say about these installations?

According to the National Electric Code, you can use 2 200 amp main disconnect panels to run a 400 amp service. 

You can also use a 200 amp sub-panel with a 200 amp service if 2 disconnect panels are costly. 

The NEC has permission for both procedures. 

 The NEC indirectly talks about the installation of the 400 amp service. 

There are no direct recommendations about dealing with the 400 amp service’s panel installations. 

The NEC only discussed the equipment requirements, installation prices, and wire types and sizes for the 400 amp service. 

Other considerations to consider

When you think of running a 400 amp, consider a few factors about how to run the service. 

If you have new constructions, your decision will undergo a few plan reviews by the building inspection department. 

The department will also suggest factors like the local additional regulations and requirements. 

Maximum localities need electrical installations and service entry points by licensed and expert electricians. 

Suppose you install it yourself with a house owner’s permission. 

In that case, you should expect the electrical inspectors to be frequent visitors to your project site for examination. 

Ensure the balance load of the electrical system. 

The electrical service panels will have 2 circuit breaker rows on every side of the panel frame. 

Each breaker set is fed with power from one leg of the 240V service provided by the service panel. 

The load balancing allows the electrical system to draw equal power from each side of the service panel. 

Some circuits will overload if one-panel side draws more power than the other. 

As a result, the circuits will overheat, and the electrical components of your house’s electrical system and other appliances will fail to operate. 

The electrical code department of some areas will ask for a load calculation of the electrical system installed inside your house. 

There are many ways to perform a load calculation balance. 

Ask your electrician to help you and give you a detailed and acceptable report about the balanced load calculation. 

Sub-panel vs. two main disconnect panels

The possibility of running a 400 amp with 2 200 amp panels or not will be better understood with the help of the local electric code. 

Some local electrical codes say that any sub-panel with a disconnect switch installed on the electrical lines will feed the panel. 

So, combining a main disconnect switch and a sub-panel is similar to installing a service panel with a disconnect panel instead of the sub-panel. 

The major factor is the cost. 

Installing a disconnect panel with the main service will cost more than installing a sub-panel with the main service. 

The costs are often more due to additional services and living areas. 

So, which one will be the best?

Though there is no problem in running a 400 amp with 2 200 amp panels, it is best to install a 200 amp sub-panel instead of having 2 panels. 

Before you decide on having 2 200 amp panels for running a 400 amp service, consider the following guidelines:

  • Check the local codes and ensure that your plan meets the codes to prevent problems later. 
  • Contact your local electrical contractor for advice and selection between the 2 main panels or a sub-panel. 
  • If you consider installing the panels, have permission and consult your electrical inspector for proper advice.

Since both options are workable, it is very difficult to recommend anyone. It completely depends upon the individual’s choice. 

Situations, codes, and needs vary. 

Final thoughts

You can run a 400 amp service with two 200 amp panels. You can either use 2 200 amp main disconnect panels or a 200 amp sub-panel with a main panel. 

Most experts recommend installing a 200 amp sub-panel instead of having 2 main disconnect panels because a sub-panel is cheaper. It is completely your choice to make. 

Before deciding on any option, ensure that your local electrical codes allow your chosen installation process. Always consult a licensed electrician for the installation.

How much wattage can a 400 amp service handle?

A 400 amp service can handle 20,000 watts at the most.

Can I install two panels next to each other?

You should maintain at least 30 to 36 inches between the two panels to adjust the panel.

Data Source: National Electrical Code, NEC Wire Table,  Electrical wiringHome wiring.

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Arthur Smith

Howdy! I am Arthur Smith, an electrical engineer who is extremely passionate about electronics. I have lived in different parts of the US and currently reside in Wisconsin. I am one of those rare children who knew what he wanted to study and do in life right from the start. I was a curious child who wanted to know how switches work and how the AC works, and I would always observe my dad whenever he would handle the wires and fix things around the house. I currently work as an electrical engineer at a reputed company and write for this blog. And I read loads of books or play video games in my free time.

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