How-To Guide #7 Electrical Service: What You Need to Know

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If you want to electrify your residence – either completely or partially – you may have questions about the electricity needed to support your transition off of fossil fuels. What electrical work will be required for any changes you plan to make? Does your home have enough service from the wires in the street, or will you need a service upgrade?  Is your electrical panel adequately sized and with enough room for additional circuit breakers? If you are a renter or condo owner or landlord, who controls the electrical service?

Some Background

Your home gets its electrical service from the utility wires in the street, connecting to your electric meter and distributed through your home’s electrical panel to all of the appliances and receptacles (outlets) in your home.

Electric Meter: Your electric meter continually measures the electricity your home consumes (in kilowatt-hours or kWh) and allows your utility company to bill you for the electricity you use.

Electrical Panel Sometimes called a breaker box, a breaker panel or a circuit panel, your electrical panel is responsible for safely distributing electricity from your utility’s power lines into branches of wiring inside your home.

Circuit Breaker An electrical safety device, housed in an electrical panel, designed to prevent a branch of electrical wiring from excessive demand and overheating, which could lead to a fire.  Unlike a fuse, which operates once and then must be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation.

You can think of the electricity coming into your home similar to plumbing. The incoming flow rate of that electricity is measured in amps and the pressure to the outlets in your walls is measured in volts.

Amp Short for “ampere”, a unit for measuring the flow rate of electricity. Older homes might have electrical panels that can handle 60 or 100 amps, while newer homes may have 200 amps or higher.

Voltage In most US homes, the common electrical outlet is 110/120 volts. When you have more powerful appliances, such as an electrical stove, the demand on your electrical system is higher and you likely need 220/240 volts.

Do You Need to Upgrade Your Electrical Service?

If you are planning to have an all-electric home, 100-amp service may or may not be adequate, depending on the size of your home and the equipment installed. If your existing electrical service is only 60-amps, you’ll eventually need to upsize your electrical service to electrify everything in your home. You will also need to have your electrician check for knob and tube wiring which can be present in older homes and can be unsafe.

Upgrading to 200 amps can be a good investment if you’re thinking of going all-electric, for example, installing an electric vehicle charger, an air source heat pump (for home heating), and other new electrical appliances in the future. However, it may not be necessary if you live in a smaller home or condo and if you plan carefully about reducing your energy demand by buying EnergyStar rated appliances that use less power, and will also cost less to operate over time. Electrical work can cost anywhere from a few hundred dollars for a relatively simple job to a few thousand dollars for a new electric panel and circuit breakers, to upwards of $10,000 to upgrade electrical service to 200 amps.

Weatherizing your home – insulating exterior walls and roof and sealing up leaky gaps at windows – can make a big difference in the amount of energy you need to heat and cool your home, and it can reduce the electrical demands of your equipment. (See our How-To Guide #2: Weatherization for details and links to Mass Save programs.)

What’s Involved?

Work with your electrician to determine:

Your electrician can determine the extent of electrical upgrades required, as well as the feasibility of electrifying some systems before needing a panel or service upgrade. It’s worth doing this review before any of your fossil-fueled appliances fail, so your electrical panel is ready for the installation of an electric version when that stressful moment arrives.

An excellent article that details how you and your electrician can assess the adequacy of your residence’s existing electric service is available from Green Building Advisor, called Does Your Electrical Project Require a Service Upgrade? The article references the National Electric Code (NEC 220.83) that describes the steps to determine if an existing electrical service can safely accommodate new loads.

Available Rebates and Tax Credits

While electrifying everything in your home costs money upfront – though energy efficiency improvements can save you money over time – the federal government has implemented rebates and tax credits to help defray some of the expenses, including upgrading your electrical panels.

A good resource is the Massachusetts Clean Energy Center, which includes a table on available incentives from both our state and the federal government.

Resources

How Your Neighbors Made the Switch

Story #1: Getting the Right Advice

The homeowner lives in an 1895 Victorian house in one of Brookline’s historic districts. The main house has three stories; there is a studio apartment with a separate entrance carved out of the first floor. She planned to convert at least some of the appliances in the home from gas to electric and started researching ideas and options. (Appliances in the studio apartment, including the stove and the dryer were already electric.) It became clear that understanding the existing capacity for electricity would be important. And it made sense to do that before investing in anything new.

The electrician who had provided service for the home for many years had retired, so a search began for someone to assess the existing electricity capacity. The first company that looked into the existing service confirmed that the house had 200 amp service, but recommended an upgrade to 400 amps. This would involve new service from Eversource, along with new wires feeding the house and a new panel with an estimated cost of over $10,000. By this point, the homeowner had done more research and determined that she hadn’t seen a single other expert suggest that anything more than 200 amps would be needed – and the house already had that. More searching.

A recommendation led to another electrician, who discovered that one of the breakers in the existing panel was defective and causing intermittent problems with the dining room light fixture. Because the panel did not have room for any more breakers, the electrician recommended a new, larger panel, but there was no need for any additional amps – 200 would be adequate for the homeowner’s plans. The total was $2,400, which included the cost of a new panel and the replacement breaker, with a team of three working for 6-7 hours. The homeowner can now move forward with her electrification plans.

IMPORTANT: Verify with your installers that they have the proper licenses and insurance, and confirm that they have or will obtain all required permits and inspections from the Town of Brookline.