Electrical Service Panels. Please proof this new inspection article.

Just remember that service equipment can have circuit breakers or fuses as well. Also in many older panels with poor connections due to oxidation in the case of a aluminum buss bar of a zinsco…you may also hear arching as well and could be a sign of problems.

In some panels be it old and new, the physical contact points of the OCPD to the contact point of the buss may not be making good contact which will generate an arch which over time will increase in heat and become a potential fire hazard to be aware of. This can come from improperly listed devices in the panels as well or over time due to age where the tension of the contact points weaken.

How can inspectors check for that?

Thanks Paul

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 on either side,The width is 30" total or the width of the equipment, not 30" on either side 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.

  • sharp-tipped panel box screws. Panel box cover screws must have blunt ends so they do not pierce the wires inside the box. Also, look for wires that pass too closely to the screw openings inside the electrical panel.
  • circuit breakers that are not properly sized. Circuit breakers should not be too large or too small for the wires they serve. Breakers can be smaller than required, ie #12 protected by a 15 amp. Breakers for air conditioners are sized under different rules and will appear to be oversized for the wire size. Check the AC nameplate for the proper minimum circuit ampacity and maximum overcurrent protection size.
  1. Why is Zinsco called out but not Federal Pacific?
  2. Circuit breakers should not be too large or too small for the wires they serve” - should be made clear this refers to the electrical characteristics, not the physical.
  3. While removing the panel, inspectors should” - should say ‘panel cover’ or ‘deadfront’.

I don’t see anything about even basic protective equipment like safety glasses.

We call out both Zinsco and Federal Pacific panels. But you have to be careful. Neither of these panels was recalled. They are just the subject of debate, with evidence that they are unsafe.

If you say it was recalled and “must” be replaced, you could end up paying for it. Just say that they have a reeputation of being problematic. Recommend further eval.

Remember also that at one point in time the clearance was less than 36" in front of electrical panels. At one point it was 24 inches back I believe in the 1940’s and 50’s…

You can hear it from the arching…makes a popping sound and crackling sound due to the gap an arch jumping across the poor contact points. You can also see this with an infrared temp. gun as well like i explained in the video I did for NACHI.

thanks guys

Service Panel Inspection:
look for any nicked wires near the screw as this may reduce the ampacity and
look for any aluminum branch wiring etc.

should be added.


Nick, what about the presence of rodents or their damage. I have not seen that in any articles; but I have not seen it in a panel yet either. As far as damage, I have seen in one of my past homes where a rodent has chewed he insulation off of a wire down to the wire. Whatever it was that did the damage seemed to have a preference for the insulation, and amazingly was able to chew off quite a bit of it without getting electrocuted. At least, I did not see a dead animal around the damage.

lol…if you are not going to add our comments then why give them…lol

Made those additions.

Sometimes I lose track of an old “pleas proof” thread if no one has added to it in awhile and I’m more concerned with the newer ones. But you’re right, I’ll try not to let that happen.