Chip C wrote:



Your box will indicate somewhere what its max circuit capacity is; this
will probably permit some but not all of the breakers to be doubles.
For example, if the box has 50 slots it may permit 60 circuits, so 10
of the breakers can be doubles.

Long answer from another current thread:
UL, as I understand it, in their standard for panels limits the number
of 'poles' that can be installed in a panel. (a 220V breaker is 2 poles,
a 12V breaker is 1 pole, a 120V tandem breaker is 2 poles.) The maximum
number of poles in a 100A 120/240V panel is 20. (In a 200A panel 40.) If
a panel has positions for 16 full sized poles it could have 4 more poles
and stay under the 20 limit. These can be installed as 4 120V tandem
breakers. To prevent more than 4 tandem breakers from being installed, a
tandem breaker has a hook to install it on the panel rail instead of the
normal SquareD U shaped clips. Only 4 positions on the rail can have a
slot to accept the hook. These breakers are called class CTL (circuit
limiting). (A 100A panel may be designed so fewer than 20 total poles
can be installed.) Previous to the class CTL panels tandem breakers had
the normal U shaped clip and could be installed in any position (or all
the positions). Last I heard these non-CTL breakers were still
available. As indicated in the quoted post, a panel on its label should
have a list of breakers that can be installed in that panel. A class CTL
panel will not have non-CTL breakers on the list and it is a code
violation to install a breaker that is not on the list.

Be aware that you may need to add extra
neutral (and less probably, extra ground) bus bars; unless the panel
says so explicitly, don't try to put more than one neutral wire under
one neutral bus screw. I *think* you can usually double up the ground
wires but I'm not certain. On this topic code says to do only what your
panel's manufacturer says is ok.

From aother current thread:
NEC 2002: 408.21 allows only one neutral per lug.
"Explicitly" is right.


2) Does the bathroom circuit have to be dedicated to the GFCI outlet ONLY or can
it also feed the vanity lights?


I've heard the answer to that and I forget it, partly because Canadian
and US codes are different on that question. Search other postings in
this NG and you'll find it.

Appears no. (NEC 210.23A)

bud--