I know this is a thin slice but, I am doing a research project that
involves octagonal electrical junction boxes. Does anyone know when
these boxes were first used in America? According to a Wikipedia
article, "knob and tube wiring (sometimes abbreviated K&T) was the
earliest standardized method of electrical wiring in buildings, in
common use from about 1880 to the 1930s." It appears to me that this
approach didn't use junction boxes much so they probably didn't come
on the scene until the thirties or so. Thanks in advance for any
Not a direct answer to your query, but you may enjoy
some background history here:
Steel junction boxes were very common by 1900 and even earlier.
Most were square, but I wouldn't be surprised if deep octagonal
ones for masonry embedment didn't appear soon after that.
Fascinating history of early electrical company here:
BTW, K&T didn't suddenly come to an end in the 30's.
It was *the* residential wiring method in some cities
way into the 60's ! In these cities, Romex was not
permitted (labor influence) and K&T died a very slow death.
As a followup, I found reference to "round" ceiling boxes
prior to 1917. These were deep-drawn steel, one piece.
The objection to them was that fittings didn't sit flush
with the box sidewall, so the octagon was used afterward.
Don't put to much stock in Wiki. While Jim is a veritable encyclopedia on
this stuff, there is also a fine book called "Old Electrical Wiring" by
David E. Shapiro that can give you a pretty good chronological breakdown of
what was available and when
The house I was raised in as a child in Niagara Falls, NY was built in
1928. NO K&T wiring when we moved in in 1941, but I believe there
might have been. Screw type fuses in a box going down into the cellar.
Electrical boxes, IIRC, were octagonal steel. There were a few of the
screw type outlets with a little metal flap. I stuck my finger into at
least one! Switches were dual push button type. Original service
couldn't have been more than 50 amps. I believe it was upgraded to 100
amps at one point when we lived there. Only major early electrical
appliances were an electric stove and refrigerator. Later, we added a
washer and dryer, which I remember required additional wiring. That
might have been when the 100 amp service was added. I have been back
to the house recently, and they have 200 amp service, and a LOT of
rewiring has been done.
My grandmother's house in Kansas, built in 1903 was K&T, later
refitted to armored cable. The house was fitted with gas lights, and I
assume some of the pipes might have been used for electrical conduit.
I worked as an electrician for an appliance store in the 50's. Common job
was replacing 120V service with two plug (screw-in) fuses and a knife main
switch (no main fuses) with a "main, range, and four" or "main, range, and
six" panel and 240V service. This was done when the customer bought an
electric range, usually. The main fuses were commonly 60A and the range
fuses were commonly 40A. Four or six fuses were usually 15A, although there
were some 20A circuits feeding kitchens and dining rooms.
Incidentally, knob and tube wiring was preferred for quite a while in areas
subject to flooding, particulary in riverside and lakeside cabins and
I've been an electrician for forty plus years. I've seen a lot of boxes
in knob and tube installations. The wire from the last knob/tube to the
box and from the box to the next knob/tube was in a woven tar
impregnated tube called loom. Many of these early boxes were black
painted common steel. They were actually round in shape. The shape was
changed to octagonal to better accommodate the lock nuts used to secure
threaded conduit to the boxes.
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