What Do You Know About Your Electrical Panel?

Electrical panels are boxes that house circuit breakers, which are are safety devices that stop the electrical current if it exceeds the safe level for some portion of the home electrical system.

A lot of people, INCLUDING experienced electricians have died or have been seriously injured while opening electrical panels. So I’ll use this line as as my disclaimer. DO NOT MESS WITH IT IF YOU DON’T KNOW WHAT YOU’RE DOING! If I could paint it in red I would. In 1991, an Atlanta electrician was killed while attempting to inspect a panel that had a faulty spring-loaded bus-bar assembly. Apparently, the bus-bar was moved while the electrician was opening the panel, causing an arc and a lethal electrical explosion.

Let me take you back to May, 2018. I was doing an inspection in St. Robert. The electrical panel was a common Square D Panel, located in the basement of a really good looking home. The house was vacant. I was in the middle of no where, alone. I took my flat head screwdriver and began to take off the cover (like I’ve done literally hundreds of times). The first 5 came out easy, however the bottom left gave me some issues. Not only was the screw stripped, it wasn’t the proper panel screw with a flat jagged edge. After tampering with this thing for about 5 minutes I finally was able to break it loose. It was about halfway out, the BAM!! Sparks flew, and I had the brightest flash right in front of my face. I was fine. I didn’t even get hit. What had happened was the screw had penetrated through the insulation of a hot wire. The more I messed with it, the more it dug, until it arced.

Like I said, I was fine. But what if the home buyer decided to not get a home inspection? What if he wanted to take a look inside that panel? The odds may not have been in his or her favor that day.

The electrical portion of a general home inspection in the beginning of my career was my least favorite part. Yea, I knew what I was looking for and what my SOP required me to look at, but I wasn’t comfortable. It was my weakest subject knowledge wise. Though my SOP is all thats required in an inspection, its also the minimum & Parker Home Inspections tries to go above and beyond those standards, and I felt like I wasn’t doing that with the electrical portion of the inspection. So I started digging. I took hours upon hours of continuing education, and now… well now its my favorite part. Opening up a panel to me is like opening up a present on Christmas. You never know what you’re about to get into. It’s almost an adrenaline rush to me.

Service Panel Inspection

Inspectors can check for the following defective conditions during an electrical panel inspection:

  • insufficient clearance. According to the 2008 National Electrical Code, most residential electrical panels require at least a 3-foot clearance or working space in front, 30 inches of width, and a minimum headroom clearance of 6 feet, or the height of the equipment, whichever is greater. If obstacles would make it unsafe for you to inspect the service panel, you have the right to disclaim it.

  • aluminum branch wiring.

  • sharp-tipped panel box screws or wires damaged by these screws. Panel box cover screws must have blunt ends so they do not pierce the wires inside the box. Look for wires that pass too closely to the screw openings inside the electrical panel.

  • circuit breakers that are not properly sized.

  • oxidation or corrosion to any of the parts. Oxidized or corroded wires will increase the resistance of conductors and create the potential for arcing.

  • damage caused by rodents. Rodents have been known to chew through wire insulation in electrical panels (and other areas), creating an unsafe condition. Rodents have been electrocuted this way, leaving an unsightly mess inside the panel.

  • evidence of electrical failures, such as burned or overheated components.

  • evidence of water entry inside the electrical panel. Moisture can corrode circuit breakers so that they won’t trip, make connections less reliable, and make the equipment unsafe to touch.

  • evidence of missing or improper bonding.  This may indicate improper wiring, damaged equipment or unsafe conditions.

  • the physical contact points of the over current protection device to the contact point of the buss are not making good contact. The sounds of arcing (a cracking or popping sound) may indicate this condition.

  • panel manufactured by Zinsco or Federal Pacific Electric (FPE). These panels have a reputation for being problematic and further evaluation by a qualified electrician is recommended. Zinsco panels can generally be identified by a blue and silver “Zinsco” label inside the panel, and an embossed “Magnetrip” label at the top of the panel face. FPE panels should include, if they were not removed, one of the following identifying labels:

    • Federal Electric

    • Federal Pacific Electric

    • Federal NOARC

    • Federal Pioneer

    • FPE

    • FPE-Stab-Lok

    • Stab-Lok

In summary, electrical panels can be dangerous. Always use care when when opening them, and if you’re not sure what you’re doing… HIRE A PROFESSIONAL!

Ethan Parker

Parker Home Inspections


Reference Credit: Nick Gromicko & Internachi