"Greg" wrote in message
...
A bathroom where you might use a hairdryer or other high
consumption device would require more latitude.

Bathrooms, kitchens and laundries require 20a dedicated circuits (2) in
kitchen.
The original question was about the general lighting circuits. In the US
these
are distributed equally based on the VA per square foot (3va) and the
receptacles are placed based on the average length of a lamp cord (6
feet). The
objective is not to have any wall space 2' or longer, not more than 6 feet
from
a receptacle and that no cord will have to be pulled across a door opening
or
other hazard.
There is no limit on how many receptacles that is since they assume you
will
not really use them all anyway. It is purely based on the projected load
of 3va
per square foot.
This is just the minimum. You can always put in more.
We plug in a lot more things than our parents but generally they use less
power. Large loads are usually put on dedicated circuits.


I have heard about those 20 amp circuits, but they are rarely used in
Canada (too bad). Here, for a kitchen the duplex receptacles are usually
wired with 15 amp circuits, but the upper and lower plug of the receptacle
must be on separate circuits. For a bathroom, 15 amp GFI-protected plugs are
the norm. Almost all home wiring is done with 14 gauge romex, not the 12
gauge wire that you more commonly use in the US. I like the increased
versatility you have, unfettered by the worry about exceeding a maximum
fixture count during the planning stage. On the other hand, if you later
discover that a circuit is overloaded and breakers are tripping, you then
have some remodeling to do.

You make a good point about the trend toward increasing use with each
generation. Whether that trend will continue is hard to say.

Dave