How To Look At A House
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Why is there no main shut-off breaker in my electric panel?
Thursday, September 5, 2019
Almost all of the thousands of house electrical systems we have inspected over the years comply with the requirement for a main electrical disconnect. It may not appear that your panel is compliant, even though it actually is, because of a couple of things:
1) A main breaker is only required at the service panel, which is the first electrical panel after the meter. Any subpanels are only required to have a disconnect breaker upstream in the main panel. Some houses have a service panel, which may sometimes contain only the single disconnect breaker, on the exterior wall next to the meter and a distribution subpanel inside the home. Condominiums often have the service disconnects integral with the meters in clusters at an exterior wall, as shown below. The meter cluster might also be in a meter room somewhere in the building. So the inside panel is technically a subpanel and does not have a main breaker.
2) The National Electrical Code (NEC) allows it to take shutting off up to six breakers in the main service panel to turn off all power. This main breaker exception has been in the code since 1933 and there was a period in the mid-twentieth century when a type of panel called a “split bus” that utilized that allowance was popular. But each disconnect breaker had to be clearly marked as a “main disconnect,” usually by affixing a sticker next to it, like in the photo below. To learn more, see our blog post What is a split bus electric panel? Split bus panels are no longer manufactured and now a just footnote in electrical history, but the allowance for up to six switch-throws to shut off all power is still sometimes used in smaller service panels, like at mobile home and RV parks.
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