Mismatched Breaker Brands?

Sometimes being a home inspector feels I’m part of a boxing match. The buyer VS. seller is the main event. The seller has an electrician in his corner, and the buyer has me. Let’s get ready to rumble.  One of the most things we write up in the electrical panel is mismatched breakers. This is when there is a breaker in the panel that is not listed to be installed in the panel. May times we get slugged with the “two electricians said it was fine” line. I find it very curious that every homeowner has exactly two electricians look at, but I am digressing. Is it a defect or not?

The “Technical” Knock Out

Every electrical panel has, or should have, a diagram and important information about the installation of the panel. Included in that information is almost always information about which kind of breakers can be installed in the panel. Most panels are straight forward-do not install any other types of breakers in this breaker. Here is a photo of a Square D label. If you can’t read it well, it says “Use of other than Square D circuit breakers may adversely affect user safety, impair reliability, and will void the warranty.” This is the knock out punch. It could not be any clearer as to whether or not a defect is present?

Here’s another label that is more inclusive of the types of breakers it allows. It says “Branch CKT BRKR are A-H Murray styles MP, MM & EP; Bryant types BRD, BRO, BAR, BR, GFCB; Westinghouse types QP, QPGF; ITE types EQP, QF.” Although void of the doom and gloom warning, it’s still clear that only certain breakers are allowed in this panel. Even more interesting is that it’s not just brands that are listed, it’s very specific models of those brands. Based on the label, a Siemens type breaker would not be allowed in this panel, as an example.

The NEC states in 110.3  “Equipment must be installed and used in accordance with any instructions included in the listing or labeling requirements”

So What’s the Problem?

The photo to the left shows two different brands of breakers. They obviously have design differences which is a clear implication of the problem. Breakers are connected to the buss bar in an electrical panel, and using a brand not specifically designed for the buss bar can cause loose connections. Loose electrical connections can cause arcing, pitting, and irreparable damage to the panel.

“But is it really a problem?”

Sometimes, its not enough to write up a defect. People want to know if its really going to cause an issue. Honestly, I don’t know. I’m not an electrical engineer. I’m a generalist and I simply go by the label for this particular issue. The good news is that it’s typically an easy fix. If you can find the breakers allowed in the panel, switch them out, and call it a day. If you can’t find an appropriate replacement breaker,  you may have to bite the bullet and replace the panel. Panel replacement can run about $1000 or more. If there are no replacement breakers available, the panel is likely old, and may be due for an upgrade anyway. Paying $1000 to know your panel is safe, is a sound investment in my opinion.