Octagonal Junction Boxes

[ted]

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 help. Ted

[Speedy Jim]

Not a direct answer to your query, but you may enjoy some background history here:

especially: 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.

Jim

[Speedy Jim]

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.

Jim

[RBM]

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

[professorpaul]

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.

[Tom Horne]

Ted 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.

-- Tom Horne

[Don Young]

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 boathouses.

Don Young