Mike Holt Electrical Exam Prep Question 2017

[sokbok]

I am studying for my masters using the 2017 electrical exam prep book.

I am confused about the two examples on page 272. Specifically, how was the size
of the neutral determined for the Feeder calculations? Figures 6-71 and 6-72.

After reviewing 215.2A and 110.14C2 I am stumped on how the neutral can be
less than 100% of the possible unbalanced loads.

On the next page, figure 6-73, the
neutral is sized in what I think is the correct fashion.

Any help appreciated.:dunce:

 

[Little Bill]

Mike sells his products on his website. This forum can be accessed from his website but we (forum members & mods) have no way of looking at the material. So we can't help with your problem/question unless you post a copy of what you are talking about.

I would suggest you contact the staff at Mike Holt's office. They will be able to help you with their material. Some years ago I used some of his material for exam prep and had to contact them a few times. They were always helpful with whatever I asked.

 

[don_resqcapt19]

He did not talk about the actual neutral load calculation in those two figures. He just said the neutral was sized at 100% of the neutral load. With the information given, there is no way to actually calculate the neutral load. You have no way of knowing how many 3 phase, line to line loads are being served by that panel. i believe that the point he is making there is that for continuous loads, you have to size the ungrounded conductors at 125% of the load, but the neural is sized at 100%.

 

[sokbok]

He did not talk about the actual neutral load calculation in those two figures. He just said the neutral was sized at 100% of the neutral load. With the information given, there is no way to actually calculate the neutral load. You have no way of knowing how many 3 phase, line to line loads are being served by that panel. i believe that the point he is making there is that for continuous loads, you have to size the ungrounded conductors at 125% of the load, but the neural is sized at 100%.

thank you very much. I was confused.