Question on commercial / dwelling load calculations.

[Davidson Electrical]

Trying to figure out if I ever need to worry about 125% of continuous loads when sizing protection devices for dwellings. On Mike's 2014 commercial calculations DVD, he starts taking continuous motors and lighting loads into consideration if OCPD is not rated at 100% of load.
is this only something to worry about when motor loads are a facor or when table 220.42 does not apply?? Thanks!

 

[Davidson Electrical]

Also:

Also:

Also wondering why we start to worry about about balancing the load before applying demand factors for marinas on 555.12. Never did that anywhere else. I kinda thought demand factors took that into consideration.?

 

[Smart $]

Trying to figure out if I ever need to worry about 125% of continuous loads when sizing protection devices for dwellings. On Mike's 2014 commercial calculations DVD, he starts talking continuous motors and lighting loads into consideration if OCPD is not rated at 100% of load.
is this only something to worry about when motor loads are a facor or when table 220.42 does not apply?? Thanks!

Generally speaking, there is no such thing as a continuous motor load under a standard calculation. See 220.14, 220.18(A), 220.50. They all essentially end up pointing to...

430.24 Several Motors or a Motor(s) and OtherLoad(s). Conductors supplying several motors, or a motor(
s) and other load(s), shall have an ampacity not less
than the sum of each of the following:
(1) 125 percent of the full-load current rating of the highest
rated motor, as determined by 430.6(A)
(2) Sum of the full-load current ratings of all the other
motors in the group, as determined by 430.6(A)
(3) 100 percent of the noncontinuous non-motor load
(4) 125 percent of the continuous non-motor load.

Now if you are calculating under one of the optional methods, it's debatable.

 

[Smart $]

Also wondering why we start to worry about about balancing the load before applying demand factors for marinas on 555.12. Never did that anywhere else. I kinda thought demand factors took that into consideration.?

Where is balancing mentioned in 555.12?

 

[Davidson Electrical]

=Smart $
yea, article 555.12 says nothing about it. But in the Mike holt DVD they only calculated the load for half the 120v receptacles.. make sense.. but we never do that anywhere else.. thanks on the comment. I never saw 220.18 (a) before..

 

[Smart $]

=Smart $
yea, article 555.12 says nothing about it. But in the Mike holt DVD they only calculated the load for half the 120v receptacles.. make sense.. but we never do that anywhere else.. thanks on the comment. I never saw 220.18 (a) before..

Because I don't have the DVD you refer to, to continue I would be commenting out of context. So I choose not to unless you provide more [and adequate] context.