Student Discussions for the "How to Perform Residential Electrical Inspections Course"

This open, public forum thread is dedicated exclusively to students currently enrolled in InterNACHI’s free, online How to Perform Residential Electrical Inspections Course .

Students may discuss course topics, ask other students questions, and share thoughts with other students.

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Will be starting this course

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studying for the test now, nice overview

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Great, @etancrell. Feel free to ask questions related to the course topics and share thoughts with other students.

Thank you, @ematthews5. Feel free to reach out to anyone on the Education Team (Contact InterNACHI) for help with your training, certification, licensing, examination, or continuing education. They’re a great resource for you.

And feel free to ask questions related to the course topics and share thoughts with other students.

Looking at the cheat sheet in the introduction section under conductor sizes,

sizing conductor cheat sheet

I’m confused how to properly read this. It looks like the AWGS grow in size from the largest number to the smallest, until you reach aught 1/0. But then the aughts grow from 1/0 to 4/0 and then jumps to 300? At what point does each conversion happen, is 4/0 the highest and then 300 is lowest or how can I tell?

The table starts out with wire gauge sizes commonly referred to as AWG.
Here that goes from #2 to #4/0, the ampacity of those conductors increase as you move down the table. Once you pass #4/0 then the condcutors are represented by their physical circular mil area which starts at 250 kcmils and increases in area as you go up in size.

The heading on this table should be changed to indicate that this can only be used for single family and dwelling units of two family or multi-family dwellings. It cannot be used for other services or feeders for other applications.


Thanks, @rmeier2. Table content at InterNACHI® - International Association of Certified Home Inspectors has been updated.


Awesome that answers it perfectly. Thanks!

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Ive taken the course and passed the test. woohoo

I finished the course and the exam but one thing that still isn’t clear to me is how service panelboard is properly grounded when it is located inside the home (not in a garage or adjacent to an exterior wall). I see many meter boxes grounded to 2 ground rods connected together under the meter box but how does the copper wire get to the panelboard when the home is a slab home and no other conduit can be seen running inside? Thank you

I am struggling to make sense of the second column. I get that the two right columns are to compare the wire diameters between Cu/Al at any given service amperage.
Is the “Solid Wire” column about the overall diameter of the SE cable at those amperages? Which doesn’t seem right- 150A SE cable at just over 1/4 in? Surely I’ve gotten something wrong!

That column is pretty meaningless because service condcutors large than #10 are going to be stranded so telling you a a diameter of a solid conductor is of little value. According to the NEC a #1/0 conductor has a diameter of .372".