On Sun, 29 Apr 2018 21:28:40 -0400, wrote:

On Sun, 29 Apr 2018 20:55:25 -0400, Clare Snyder
wrote:

On Sun, 29 Apr 2018 20:20:44 -0400, wrote:

On Sun, 29 Apr 2018 15:34:02 -0400, Clare Snyder
wrote:

On Sun, 29 Apr 2018 10:54:41 -0400, wrote:

On Sun, 29 Apr 2018 08:43:33 -0400, Clare Snyder
wrote:


Previous to 1974 in Canada. Had pullouts in my old fuse panel -
house built in 1974. Helped my dad wire houses in the sixties and thry
were all paired then too. That was for not only single yoke but any
time the 2 circuits existed in the same box (lighting switch on one
circuit and recepotacle on the other in a ganged box, as an example -
or two lighting switches on different circuits)

How do you "pair" fuses for general lighting circuits. They are
usually screw in plug fuses. That is why the code did not require it.
Fromwhat I remember, Canadian code required separation of the
circuits UNLESS the fuses were "ganged".

In MOST cases the circuits could be easily separated, not having 2
lseparate live feeds in a single box. In situations where that was not
possible or feasible, the "ganged" fuses were required.
In actual real-world situations, it was not common to run into the
situation.

My house had a "stove block" a "drier block" plus 4 ganged fuse
pullouts - 2 for kitchen outlets, one for the AC and one for another
"edison circuit" The fuse and drier blocks had cartridge fuses - the
rest were plug fuses.

Back in the 1969 code book - section 12-296 is states "conductors of
different systems shall not be installed in the same box,, cabinet, or
auxilliary gutter unless:

1 a barier of sheet steel not less than 0.0528 inch (16msg) or ane
equivalent device of acceptable insulation material is used to devide
the space into separate compartments for the conductors of each system
- - - - - . Therer are exceptions listed

Also, in14-032
In branch circuits derived from a 3 wire grounded neutral systen
(Edison circuit) 2 single pole manually operable circuit breakers may
be used in lieu of a 2 pole breaker, providing that:
1) their handles are so interlocked that all ungrounded conductors
will be opened by the manual operation of either handle; AND
2) each breaker has voltage ratings not less than that of the 3 wire
grounded system

So the linked breaker was required by (at least Canadian) code as
early as 1969 for Edison circuits, and separate "systems" (read that
as circuits) were not allowed in the same box.. I could look it up in
1966 code too if I could find my book. My '69 book was close at hand.

"Different systems" does not apply, that refers to separately derived
systems or services with different voltage characteristics.
I am not quite sure how they could have specified "breakers" in 1969
since fuses were still pretty popular. The NEC had no such
requirement.
I agree if breakers were present, you might make that stick but
multiwire circuits predate the first breakers by decades.


They also pre-date "standards"

The first version of the NEC came out in 1898 in New York City.


And I own a copy of the "american electrician's handbook" by terrell
Croft first printed in 1913 and reprinted in 2014 by McGraw-Hill Book
Co in New Yoirk - passed down through the family