Dwelling unit load calculations - confused by example in exam prep book (2020)

[ChesterDawg]

Hi,
I'm going through the 2020 version of the exam prep book and I'm confused by the first example question for a dwelling unit load calculation.

The calculations end up coming up with 322 amps, but the answer says to use a 400 amp disconnect.

350 amps is listed as a standard breaker size in 240.6(a) and also listed in 310.12 as a service size.

What am I missing?

thanks

https://imgur.com/a/I7cBxKD

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[don_resqcapt19]

I think the answer may be based on using a fusible disconnect, but those are rare now days. You are correct that a 350 amp enclosed breaker could be used for this service as long as it is listed as suitable for use as service equipment.

 

[ChesterDawg]

Thank you. I felt like I was missing some final step in the load calculation, but I couldn't find what it was in the code book.

Feeling better about just chalking it up to an error/outdated information in the exam prep book now.