The fact that a brand of breaker that does not match the panel manufacturer will snap into place on the bus bar does not mean that it is alright to use it. But it is possible—and code approved—to use a different brand breaker if it has UL approval. The National Electrical Code (NEC) requires any electrical component to be “listed and labeled” for its intended use, which means approved by a nationally recognized rating agency like Underwriters Laboratories (UL) and marked as such, before it can be installed in an electrical system.

    There are manufacturers that have gone to the expense of getting UL approval for installation of their breakers in another company’s panels. Siemens, for example, has a type QD breaker that has UL approval for installation in a Square D QO panel, and the photo above shows Square D and Siemens breakers in the same panel. 

    They are called “classified breakers” because UL has classified them for use in another manufacturer’s panel. To learn more about them, go to our article What is the difference between specified and classified circuit breakers? Many manufacturers, but especially Square D, take a dim view of classified breakers and print a statement similar to the following one in their panel installation manuals:
    It is beyond the scope of our work as home inspectors to determine whether a particular manufacturer’s breaker is approved for installation in another manufacturer’s panel. But, when we come across an older panel with a jumble of different brands and ages of breakers that we are pretty sure are not all rated for use in that panel, we put a note in the report something like this:

“This panel has circuit breakers in use that are not manufactured by the company that manufactured the panel itself. Panel manufacturers void their warranty when this occurs, it may also void the UL listing of the panel, and could result in property loss or injury due to failure of the equipment. We recommend evaluation by a licensed electrician and repair as necessary.”

    We recently saw an extreme example a panel with a collection of mismatched breakers. The panel box shown below was manufactured by General Switch, a company that has been out of business for decades, but only the main breaker at the top was made by General Switch. The rest of the breakers were from Cutler-Hammer, Challenger, GE, ITE, and Square D. 

Also see our articles How often should I exercise the circuit breakers in my electrical panel? and Does a subpanel have to be the same brand as the main panel? and How do I find out the manufacturer of an electrical panel?  

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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 is an electrical panel overcrowded with too much wiring?

• 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 happens when you press the "TEST" button on a circuit breaker in an electric panel?

• What is a Dual Function Circuit Interrupter (DFCI)? 

• What is the difference between a Combination Arc Fault Circuit Interrupter (CAFCI) and an Arc Fault Circuit Interrupter (AFCI) circuit breaker?  

• What is the difference between "grounded" and "grounding" electrical conductors? 

• What does it mean when a wire is "overstripped" at a circuit breaker?

• Why is an old fuse panel dangerous?  

• Who is the manufacturer of those "bad" electric panels?

• Why is the circuit breaker stuck in the middle? 

• What is a double tap at a circuit breaker?

• What is the right electric wire size for a circuit breaker in an electric panel?

• What is the right size electric panel for a house? 

• What do I need to know about buying a whole house surge protector? 

• 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.