Every residential electric service needs a “main disconnect,” which is usually a single breaker, set apart at the top (or bottom) of the panel from the cluster of distribution breakers. But a main disconnect does not have to be a single breaker. The National Electric Code (NEC) allows up to six circuit breakers or switches, grouped together, to be the main disconnect. In other words, it is acceptable to take up to six switch-throws to shut off all the power to a home.

    The current rule allowing a maximum of six breakers or switches grouped together or in a single enclosure first appears in the 1937 edition of the NEC. Each switch or breaker must be clearly marked as a MAIN DISCONNECT, as in the photo above, which shows the top area of a “split bus” panel with identifying stickers down the center. These panels typically had four or six breakers for the main disconnect and were only manufactured from the mid-1960s to the mid-1980s.

    Although up to six breakers can still be used as a main disconnect today, we rarely see more than one. Also see our blog post Why are old electrical components not always "grandfathered" as acceptable by home inspectors?

• • • • • • • • • • • • • • • • • • • • • 
Field Guide for Home Inspectors, a quick reference for finding the age of 154 brands of HVAC systems, water heaters, and electrical panels, plus 210 code standards for site-built and manufactured homes, and the life expectancy rating of 195 home components. Available at amazon.com for $19.95.
• • • • • • • • • • • • • • • • • • • • • •  

Here’s links to a collection of our other blog posts about ELECTRIC PANELS:

• What causes copper wires to turn green or black in an electric panel?  

• What is the maximum number of circuit breakers allowed in an electric panel?

• When should a corroded or damaged electric panel cabinet or disconnect box be replaced? 

• What is a tandem circuit breaker? 

• When did arc fault circuit interrupter (AFCI) breakers first become required?

• Can an electric panel be located in a closet? 

• Can an electric panel be located in a bathroom? 

• Can you add circuit breakers by different manufacturers to an electric panel if they fit?

• My circuit breaker won't reset. What's wrong?  

• What is a split bus electric panel?

• How do I identify a combination AFCI (CAFCI) circuit breaker? 

• What does a circuit breaker with a yellow or white test button indicate? 

• What is the maximum gap allowed between the front of a recessed electric panel box and the wall surface surrounding it? 

• What are the requirements for NM-cables entering an electric panel box?

• Why is a fuse box/panel an insurance problem for homebuyers? 

• Why is bundled wiring in an electric panel a defect?

• Why do some breakers in my electric panel have a "TEST" button on them?

• What is the maximum allowed height of a circuit breaker (OCPD) above the floor?

• What is the maximum height you can mount an electric panel above the floor? 

• What is the code required clearance in front of an electric panel?

• What is the main bonding jumper and where do it find it in an electric panel? 

   Visit our ELECTRIC PANELS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.