The Complete Guide to Electrical Amperage in Rental Properties—Choosing Apartments That Won't Trip Circuit Breakers and How to Change Your Amperage

What is "Amperage" in Rental Properties?

An "Ampere (A)" is a unit of measurement for the flow of electricity (electrical current). "Amperage" refers to the maximum amount of electricity that can be supplied to each home; when you try to use more power than this limit simultaneously, your circuit breaker trips.

In typical Japanese homes, 30A, 40A, and 60A are the most common. In rental properties, the contracted amperage is already set, and you can see the number written on the lever of the "main circuit breaker" in the electrical panel (breaker box).

The Relationship Between Amperage and Power

• •Power (W) = Voltage (V) × Current (A)
• •The standard voltage in Japan is 100V
• •With a 30A contract, you can use up to a maximum of 3,000W (3kW) simultaneously

Required Amperage Guidelines by Living Situation

Single-Person Households (Studio/1-Room Apartments of 20–30 m²)

In most cases, a minimum of 30A is sufficient. However, if you use a microwave or hair dryer at the same time as your air conditioner, your circuit breaker may trip.

Example of Electrical Current Used When Running Major Appliances Simultaneously on a 30A Contract

As you can see, using these three appliances simultaneously reaches the 30A limit.

Couples/Families with Two Income-Earners (1LDK or 2LDK)

40–60A is the standard choice. If you cook while running multiple air conditioners and operating a washing machine simultaneously, 60A provides peace of mind.

Families with Children (3LDK or Larger)

Plan for 60A as a baseline; if your property has an electric water heater or induction cooktop, you'll need 60A or higher (some properties have larger-capacity settings such as 100A on a three-phase system).

Causes of Circuit Breaker Trips and Solutions

Common Times When Circuit Breakers Trip

• •Morning preparation time (hair dryer + microwave + air conditioner)
• •Extreme seasons (summer and winter) when air conditioner power consumption increases
• •Simultaneous use of electric kettles, rice cookers, and microwave ovens

Solution 1: Stagger the Use of High-Amperage Appliances

The simplest solution is to stagger the use of high-amperage appliances.

• •Use your microwave after you're finished with your hair dryer
• •Set your rice cooker's timer for before you leave for work (after you've finished using your air conditioner)
• •Run your washing machine at night and avoid daytime use

Solution 2: Upgrade to Energy-Efficient Appliances

Older appliances consume more power, so upgrading them creates more amperage headroom. Air conditioners, refrigerators, and hair dryers offer particularly significant energy savings.

Solution 3: Change Your Amperage

The most fundamental solution is to increase your amperage.

How to Change Your Amperage and Important Considerations

The Process for Changing Amperage

1. Contact your local power company by phone or online to apply for a change
2. A power company representative will visit to verify or replace your smart meter
3. The change is completed (typically within 1–2 weeks)

You'll apply with your local power company (Tokyo Electric Power Company, Kansai Electric Power Company, Tohoku Electric Power Company, etc.).

Cost

Changing your amperage itself is basically free, but if your electrical panel needs to be replaced, you'll incur construction costs (approximately ¥20,000–¥50,000).

In addition, increasing your amperage will raise your base rate.

Sample Base Rates Under the Tiered Rate Plan (as of 2026 / Tokyo Electric Power Company example)

If you change from 30A to 60A, your base rate will increase by approximately ¥858 per month.

Important Considerations When Changing Amperage in Rental Properties

Before changing your amperage in a rental property, check with your building management company or landlord to see if permission is required.

• •Smart Meter Only (handled by power company): No construction work required; permission is typically not necessary
• •If Your Electrical Panel Needs to Be Replaced: This counts as a modification to the building's electrical system, so you'll need the landlord's permission

Additionally, when you move out, you may be required to restore the electrical panel to its original condition as part of the restoration to original condition clause. Check your lease agreement and building regulations before proceeding.

How to Check Amperage When Choosing a Rental Property

When selecting a rental property, you can check the amperage using the following methods:

1. Ask your real estate agent: Ask "What is the current amperage?" in Japanese ("現在のアンペア数は何Aですか").
2. Check the electrical panel during your viewing: The amperage is written on the lever of the electrical panel (breaker box).
3. Review the property floor plan and equipment list: The amperage may be listed as "Electrical Capacity: 60A."

Older properties (built in the 1980s or earlier) often have low amperage of 20–30A, which may be insufficient for modern all-electric living. For properties with multiple air conditioners installed, 60A or higher is recommended for peace of mind.

Summary: Amperage Checklist

Here's a summary of amperage considerations for choosing a property and managing circuit breakers after you move in.

When Choosing a Property

• •Check the amperage on the electrical panel during your viewing
• •Calculate the power consumption of the appliances you plan to use (number of air conditioners, electric cooktops, etc.)
• •Confirm with the building management company whether you can change the amperage

After Moving In

• •Create a schedule to avoid using high-amperage appliances simultaneously
• •Know how to restore power if a circuit breaker trips (the location and operation of your electrical panel)
• •Upgrade to energy-efficient appliances to reduce power consumption

While amperage may seem like an unglamorous specification, it directly affects your daily comfort. Checking amperage during viewings and choosing a property with electrical capacity suited to your lifestyle is essential preparation for avoiding frustration after you move in.