# Inspecting the Main Electrical Panelboard During a Home Inspection

Enjoy reading this new inspection article, “Inspecting the Main Electrical Panelboard During a Home Inspection.”

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Love it.
Newer Inspectors should click the link and once the page opens up, save it to their phone for quick reference. It would take no longer than three minutes to scroll and whalla, an inspector who isn’t asking other Inspector’s to do their work for them on a Facebook page for Home Inspectors. They would actually learn something instead of having other’s to do their job for them.

Good job InterNACHI.

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This is from the article:

“Whether it arrives overhead or underground, a 3-wire service consists of a service neutral and two energized (hot) service conductors—which are also called Service Phase A and Service Phase B—two phases of alternating current. Three-wire service delivers 120v relative to ground and 240v between the energized conductors.”

Seriously guys? It is a SINGLE-PHASE service. SINGLE means ONE. There are not two phases. Two-phase systems are rare and are generally considered to be obsolete (though some still exist, most of which are in the Eastern US).

There is a SINGLE continuously wound primary coil on the supply transformer and a SINGLE continuously wound secondary coil. The secondary coil has a tap in the center. It could have multiple taps, or the tap could be somewhere other than the center, but it would still be a SINGLE PHASE. The two legs, which are the ends of the SINGLE coil are NOT separate phases. They are two ends, or LEGS, of the same coil.

The Peak-to-Peak Voltage of a 240Vrms SINGLE-PHASE system is approximately 340Vpp (nominal). That means that the Peak Voltage in one direction is approximately 170Vp with an RMS (effective) Voltage of 120Vrms relative to the Center-Tap. The Center-Tap is 0V relative to Ground. It is because of the Center-Tap being at the point where the Voltage is 0 that we can derive two 120Vrms Legs on the SAME SINGLE PHASE.

Saying that there are two phases is not only wrong, but it adds to the confusion that inspectors with little or no electrical background already have.

I hope you guys will do the right thing and correct the egregious errors in the article. Maybe next time you will consider having an electrical professional proofread your electrical articles.

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Doesn’t matter how many times it is explained they still get it wrong!

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The GEC (grounding electrode conductor) cannot terminate on the EGC bus as depicted in the graphic.

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Hi, @rmeier2. Which graphic is that? and could you email it to me instead of posting here? Thank you so much.

Sure but here it is for those following along.

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Hi, @gwells. We asked several members to review the article and make recommendations for edits on accuracy and clarity, including some members here on this thread. We’d love to have you also review and contribute, if you’re interested. Feel free to email me your thoughts, if you have any extra time to help. Thanks! ben@internachi.org

Thanks, @rmeier2. When the service neutral conductor is connected to the service disconnect [Sec. 250.24(B)] by a wire or busbar [Sec. 250.28], the GEC can terminate to either the neutral terminal or the equipment grounding terminal within the service disconnect [Sec. 250.24(C)(4)]. Maybe we can move this point to email. And that way, I can have others join our conversation by email.

Many of us here are learning about some of these intricacies too. So, moving this point to email will exclude us.

Maybe those “others” you speak of could join the conversation here.

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Why are you pushing so hard for private conversations? Isn’t the whole purpose of the message boards for a place for everyone to learn?

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Yes, please keep it here! I need to understand @rmeier2 's point about the GEC not being able to be connected to the EGC bus as depicted in the image.

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I understand the point, but staff does not use the forum to make edits to training content.

Yet here you are. This is 100% training content when there is a discussion.

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two phases of alternating current.

Did this statement not get reviewed because this is an incorrect statement and perpetuates confusion? I’d recommend including @gwells @rmeier2 and @rkenney to name a few in any discussion about anything and everything pertaining to electrical training. They have been huge contributors to my training.

Maybe its time to start?

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In fairness they did reach out to me to review the material but it was nearly 40 pages long and I’ve been too busy to give it an adequate review.

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I’ve think I’ve got it now but please someone correct me if I’m wrong. According to one of his posts on an older topic: Ground Rod tied to Neutral Bus.

The GEC is required to land on the neutral bus, not the EGC bus, when the MBJ is a screw.

@bgromicko1 is citing the code “by wire or busbar” but the image does not depict a wire or busbar as the MBJ

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