Determining Your Home's Electrical Service Size: How To Check And Verify Amp Size

27 October 2015
 Categories: Construction & Contractors, Articles


The amp size of the electrical service within your home will determine how many electric appliances or fixtures you can run at once without overloading the system. Amp sizes vary between 60 amps to 200 amps, with the average home having a service size of 100 amps, depending on the blueprint of the home and when the home was built. Naturally, older homes tend to have a smaller amp size for their electrical service. Finding out the amp size to determine how much your home's electrical service can handle is a piece of cake and can be accomplished in several ways. Those who are uncomfortable or unfamiliar with electric wiring or circuitry should highly consider relying on professional assistance instead to prevent accidents like electrocution.

Importance of Verifying Compatibility

Before going through the different ways on how to check the amp size of the electrical service of your home, you must first understand the importance of compatibility. The amp size of all of the components of the electrical system in your home must be compatible and the same. If there is an incompatibility present, then you may be looking at a potential fire hazard.

Not all components may be compatible at all times, and some of the components may have a larger amp size than others. If this is the case, you can generally assume that the amp size of your home is the lower number, so that the entire system can handle the current and voltage size. In particular, the electrical system will need to be compatible with the main fuse or breaker. Regardless, you should always get a professional electrician to verify the amp size if the recorded amp size for each component simply isn't the same. It's better to be safe than sorry.

Ways to Check Amp Size

There are a couple of electric components that you can look at to check amp size. The main components in the electrical distribution system that will give you a good idea of the amp size of your electrical service include the wire, the conduit, the meter, the panel and the main breaker. To check the amp size, you will want to:

  • take a look at the amperage rating recorded on the electrical meter, the electrical panel and the main breaker or fuse. Usually, the amperage rating is printed on a label found on the body of the component. Also, make sure you do not open the electrical panel itself since it contains many exposed wires that could potentially harm or kill you.
  • inspect the gauge of the main service wire. The size of the service wire will indicate the maximum current it can handle. In general, a 6 gauge copper wire can handle 60 amps while a 250 MCM copper wire can handle 200 amps.
  • measure the diameter of the conduit, which is basically a pipe that holds the main electric wire for your home. A 1 inch conduit will generally indicate that the service size is approximately 60 amps. The conduit can be oversized, so the measurements may not necessarily be accurate.


Once you have determined the electrical service size of your home, you will be able to ensure that you use your electricity accordingly and efficiently. For example, you'll get a better idea on how many appliances you can run at a time without having to worry about a thing. You may also get an idea as to whether the electric system within your home needs to be upgraded or not. A licensed residential electrician from a company like All American Air & Electric, Inc. can help you easily determine not only the electrical service size of your home but whether any improvements or upgrades can be made for higher energy efficiency.