According to frank-in-toronto :
"Charles Bishop" wrote in message
...
I was working in the kitchen, replacing the outlets near the sink with
GFCIs. When I went out to turn the breaker off, I found out that the
breaker that turned off the five outlets was two 20A breakers that had
been connected in the panel as if they were a 20A 240 V circuit. When I
disconnected the two of them, I found that one breaker controled the
outlets on the left hand side of the sink (2 outlets on the counter, one
for the refigerator and one for the microwave) while the other breaker
controlled 3 outlets on the right side of the sink.
What's the reason for connecting the two breakers together in the breaker
box? If there is a short in one of the outlets on the right hand side,
will both breakers together trip as easily as the one would by itself?
On Mon, 17 Jan 2005 20:44:09 -0500, "RBM" rmottola1(remove
wrote:
It is code when both circuits are fed from a three wire cable, sharing the
neutral
it sounds to me as if code is broken here. in ontario the fridge
needs to be on it's own circuit. and outlets beside the kitchen sink
have a separate breaker for top and bottom. these breakers ONLY
control/feed that outlet. maybe this is different elsewhere.
As mentioned elsewhere, Canadian code is different. For example, Canadian
code requires a separate circuit for the fridge (can only be shared
with a clock). US code does not. The main reason is that US code encourages
20A general purpose 120V circuits, but they were illegal in Canadian code
until recently, and sharing a 20A circuit with a fridge isn't as bad
as sharing on a 15A circuit.
Up until recently, Canadian code explicitly required 15A split-duplex (officially
"multi-wire-branch" circuits) with dual gang-trip breaker, circuit per half of
outlet for kitchen counters. These circuits could feed at most two non-adjacent
receptacles,
Split-duplex circuits _were_ common in the US, and still permissible
[subject to GFCI reqts. below] for kitchen counters but the US has
mostly switched to 20A non-split circuits. Which was fortuitous,
because the US has been gradually increasing the requirements for GFCI
on kitchen counters, and now _all_ counter outlets must be GFCI'd.
Canadian code is now "catching up" with the NEC regarding GFCI on kitchen
counters, and now explicitly permits unsplit 20A 120V circuits with GFCI as
a substitute for split duplex 15A. Further, if you still want to use split
duplex, you have to use a dual GFCI breaker.
[Candian code simply didn't permit the 15/20A dual-use 120V circuits so common
in the US _until_ the 20A GFCI'd kitchen counter outlet stuff came along a
few years ago.]
Part of the issue with split/non-split and GFCI is that a non-split receptacle
can be GFCI'd with a cheap GFCI outlet. To GFCI a split circuit, you need
a very expensive dual GFCI breaker (or use _five_ conductor cable and/or large
boxes with two GFCIs in them). So, to keep costs in check, Canadian code
is "borrowing" the US arrangement.
[I still think the split-duplex 15A solution is better than a single 20A,
but it's now very expensive to meet code on them for kitchen counter
purposes. They're still great, legal and cheap for a workshop.]
Another US/Canadian (subtle) "difference" is the gang trip requirements
for multi-wire branches. US code permits multi-wire branch circuits to _not_ be
gang-tripped if no "strap" (essentially device) is fed from both legs.
Canadian code essentially says a multi-wire branch circuit MUST be
gang-tripped period, and furthermore, you can't feed multiple circuits
into a box _unless_ there's a single disconnect or there's a physical
barrier to prevent contact with both sides. [Which explains why our
main panels are slightly different than US ones.]
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
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