Residential Inspection Course - Terminology

I just began the electrical section of the online course. I have decades of electrical industry experience though so I expect this section to have more familiarity to me than other inspection courses. There were a few thoughts I wanted to share after going through the introductory “Basic Terms” section.

I noticed right away that while the lesson emphasizes why using terminology correctly, it does not address term differences between panelboards and load centers. Rather, it refers to everything as panels or panelboards. This is not correct, but is not an uncommon mistake made outside of the electrical industry. There are several distinctions, with residential utilizing primarily load centers instead of panelboards for power distribution, however I understand if this is being simplified deliberately for introductory coursework. Do many professional inspectors refer to residential load centers as panelboards though? I hope not for the same accuracy reasons presented in the lesson.

Another area is the paragraph referring to SE & SEU cable. I think it would be better to refer to SER and SEU cables and their differences as they are the two types inspectors are likely to see.


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Welcome to our forum, Thomas!..enjoy participating.

P.S. I referred to them as “cabinets”.


I use Service Panels and Remote Distribution (sub) Panels.


Panelboards is the term that is used in the IRC. This is the term I use in my inspection reports.

When I look up information from the manufacturers such as Square D they also use the term panelboard.

Are you a licensed electrical contractor?


The term ‘load center’ does not appear in the NEC. The following does:

Panelboard. A single panel or group of panel units designed
for assembly in the form of a single panel, including buses and
automatic overcurrent devices, and equipped with or without
switches for the control of light, heat, or power circuits;
designed to be placed in a cabinet or cutout box placed in or
against a wall, partition, or other support; and accessible only
from the front.

Neither ‘service panel’ or ‘distribution panel’ appear either. The NEC calls both “Service Equipment”

Service Equipment. The necessary equipment, consisting of a
circuit breaker(s) or switch(es) and fuse(s) and their accessories,
connected to the serving utility and intended to constitute
the main control and disconnect of the serving utility.

I usually just call out main panel and sub panel.

The argument has been made that proper nomenclature is essential to letting the service electrician know what the problem is, but I write my reports for the “common Joe” to understand.


What is the difference between a load center and a panelboard?
As far as UL and the NEC standards are concerned, there is no difference between a panelboard and a load center.

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Load center is just a marketing term with no NEC definition. A panelboard is the interior section of the panel that contains the bus, circuit breaker mounts, etc. and is covered under NEC Article 406. The enclosure that holds the panelboard and is usually supplied with a cover is a cabinet, cabinets are covered under Article 312. IMO the term load center should not be used in a report.


Since the NEC does not specifically distinguish between them, for the scope of an inspector then it should be fine then not to be too picky about the difference. Here is the full except from Eaton as noted above, which is very similar to SquareD’s.

A load center provides similar functionality in a power distribution system as a switchboard and a panelboard. As far as UL and the NEC standards are concerned, there is no difference between a panelboard and a load center. In North America, the electrical industry refers to smaller, lower cost panelboards sold primarily in residential applications as load centers. Panelboards are typically deeper than load centers and can accommodate both bolt-on circuit breakers as well as plug-in breakers, whereas a load center is limited to plug-in breakers.

In the SquareD example cited above, Type NQ is one of their commercial panelboard products. Their load centers are designated Type QO and Homeline, and are referred to as such.

For an estimator or project manager working for an electrical contractor, or the manufacturer though the distinction is much more important. Commercial specifications almost universally reject load centers for their applications. When working on multi-dwelling residential construction such as large apartment complexes, condominiums, and townhouse complexes the distinction is an important cost and design consideration. If the specifications exclude them, as they often do even in multi-dwelling residential designs they must use commercial panelboards instead.

I appreciate everyone’s insight on this from an inspector’s point of view, and I concur the terminology is probably outside of the necessary terminology for inspection reporting. I will advise you though, the distinction is common for electrical contractors and manufacturer’s representatives, and they can be quite picky about it so keep that in mind when you deal with them. I also appreciate the warm welcome everyone. Thank you.


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I agree and I do not think an electrician or your client would have difficulty understanding your description in a residential application.


This is something a home inspector will never have to deal with so it’s of no concern. Coming from a commercial,industrial and nuclear plumbing/pipe fitter background you need to wear a different hat when referring to residential equipment. One example is referring to a toilet as a water closet will confuse your client.

I prefer to use terms in the manufactures installation instructions and the IRC and NEC.


Get used to it. Seriously! I’m not saying to give up the fight for proper terminology though. I am often chastised for correcting home inspectors for using improper terminology, including right here on this forum.

I could spend hours giving you examples. One that is ubiquitous among home inspectors is calling box covers Dead-fronts, whether they are or aren’t. Any time most inspectors see two ungrounded conductors with a single grounded conductor, they call it a Multiwire Branch Circuit, whether it is or not. They speak of Floating Neutrals which, as we know, do not exist in residential electrical systems. The list goes on and on and on … ad nauseam.

This is my 48th year in the electrical trades. When I was an apprentice, proper terminology was hammered into us. It is part of being a professional. When was the last time you heard anyone refer to a Made Electrode? I’ll guess that it has been a long time.

Today, people don’t even care about basic grammar. Hardly anyone writes complete sentences using proper grammar in home inspection reports. As an industry, home inspectors don’t seem to be much interested in learning or using proper electrical terminology.

I stopped getting on this forum regularly when an InterNACHI staff member, Kenton Shepard, chastised me for using proper electrical terminology. He accused me of obfuscation. He said I was confusing inspectors by using proper terminology.

As I said, don’t give up the fight but get used to it. You aren’t likely to improve things much.

It is possible to do both.

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