Breakers are more convenient, but fuses are more reliable - they don't require regular maintenance and they don't get stuck closed. You still see them in some places.
The house I grew up in was built in the 1700s. Walking through the basement and house was seeing the illustrated history of electricity (knob and tube through Romex) as well as heating (fireplaces through oil boiler and radiators eras}.
I have worked in a home that was on our local "Historic Registry" that maintains all its original style wiring (knob and tube) and yet still functions as intended. Great care has been taken to maintain it, but it still does the job. Great care was taken when I was working on the elevator that was installed in the early 20th century. They don't use it much, but I'm prepared to believe that even now it's still plugging along. :^)
Just rewired my garage with a new panel and 20 amp circuits. Old knob and tube stuff was all pulled out. Still very common here in northern Ohio. But being the packrat that I am, I saved all the ceramic knobs to use for something... what?
The other reason for the 'tubes' was to help isolate the wires from damp wood.
note that both the tubes and the knobs were also vitreous fired on their outer surface, to help prevent water from creeping into the insulation.
I've worked on several houses with this kind of 'relic wiring.' Most of the time the wire was at least 14 if not 12 gauge, so the wiring itself would easily carry 15 or 20 amps as long as the cloth wrapping was intact. That's not based on just the modern Electrical Codes, but the actual fuse plan laid out on the fuse box itself. I can remember a couple of situations where the ceiling light circuit was only 16 gauge, but that circuit was usually three or four ceiling lights in a string, with one circuit for each side of the house.
My little house in Ohio still had knob and tube wiring and fuse boxes, no cloth wrapping. That was the first thing I fixed, Along with reporting to the electric company that the house I had just bought, which had set empty for a decade, still had jury rigged power from a squatter. Scared the crap out of me when the circuit I was working sparked
I remember changing the old fuses. I've seen knob and tube. My sister's house had it, and they HID it, by splicing in Romex just prior to all of the outlets and switches. When they found out the deceit, a few years later, they had to gut and rewire the entire house.
My in-law's home had all the old infrastructure. Oil fueled boiler, aluminum electric wiring, cast-iron(?) drain pipes running to the septic, etc. Wasn't cheap dragging it into to the 21st century. 💸
The aluminum wire was likely a 1960s rewire job, as it became less expensive than copper around 1965, at least in the Mid Atlantic region, despite requiring two full gauge sizes larger wire - 10 instead of 12 for a 20 amp circuit, for example. Dad did a partial rewire of our house in that time period, as he was more or less finishing the attic for my room - 3 bedrooms, four kids, with two of my sisters only a year apart, so they could share a bedroom.
Some of the early stuff was as small as 16 gauge, so yes, 10 amps would have been the limit.
The house I did most of my work in was rebuilt in the early 1930s, after the original 1910 Craftsman Bungalow was mostly destroyed by a tornado. It had piped gas ceramic heaters, two chimneys - one for a fire place, the second probably for a coal stove heating the connected bedrooms, swinging doors for both interior kitchen doors, and multipane doors between the dining room and the living room. There was also a small detached garage with an attached servant's quarters. The roof deck and interior walls were ship lap true 1 inch yellow pine. The rafters, joists and wall studs were all true 2 inch yellow pine - all hard enough that I had to drill pilot holes to hang pictures!
The wiring I was working with was mostly 12 gauge tube and knob, with some of the 1950s rewiring being Romex 10 gauge 3/G for the dryer, stove, and an air conditioner later mounted in the Dining Room Window.
it's better not to say how the grounds were run for the wall sockets!
And we were only the second family to occupy the home.
My 1909 house still has knob and tube feeding the upstairs bathroom. I rewired the bathroom during a renovation and had the choice of leave it alone or doing lots of rewiring. I left it alone. The bathroom is updated, the feed is not.
Breakers are more convenient, but fuses are more reliable - they don't require regular maintenance and they don't get stuck closed. You still see them in some places.
The house I grew up in was built in the 1700s. Walking through the basement and house was seeing the illustrated history of electricity (knob and tube through Romex) as well as heating (fireplaces through oil boiler and radiators eras}.
That must have been amazing to see, and to try to figure out!!!
I have worked in a home that was on our local "Historic Registry" that maintains all its original style wiring (knob and tube) and yet still functions as intended. Great care has been taken to maintain it, but it still does the job. Great care was taken when I was working on the elevator that was installed in the early 20th century. They don't use it much, but I'm prepared to believe that even now it's still plugging along. :^)
Just rewired my garage with a new panel and 20 amp circuits. Old knob and tube stuff was all pulled out. Still very common here in northern Ohio. But being the packrat that I am, I saved all the ceramic knobs to use for something... what?
I don't know.
The other reason for the 'tubes' was to help isolate the wires from damp wood.
note that both the tubes and the knobs were also vitreous fired on their outer surface, to help prevent water from creeping into the insulation.
I've worked on several houses with this kind of 'relic wiring.' Most of the time the wire was at least 14 if not 12 gauge, so the wiring itself would easily carry 15 or 20 amps as long as the cloth wrapping was intact. That's not based on just the modern Electrical Codes, but the actual fuse plan laid out on the fuse box itself. I can remember a couple of situations where the ceiling light circuit was only 16 gauge, but that circuit was usually three or four ceiling lights in a string, with one circuit for each side of the house.
The ceramic tubes also make good honing stones for your knives.
John in Indy
My little house in Ohio still had knob and tube wiring and fuse boxes, no cloth wrapping. That was the first thing I fixed, Along with reporting to the electric company that the house I had just bought, which had set empty for a decade, still had jury rigged power from a squatter. Scared the crap out of me when the circuit I was working sparked
I remember changing the old fuses. I've seen knob and tube. My sister's house had it, and they HID it, by splicing in Romex just prior to all of the outlets and switches. When they found out the deceit, a few years later, they had to gut and rewire the entire house.
My in-law's home had all the old infrastructure. Oil fueled boiler, aluminum electric wiring, cast-iron(?) drain pipes running to the septic, etc. Wasn't cheap dragging it into to the 21st century. 💸
The aluminum wire was likely a 1960s rewire job, as it became less expensive than copper around 1965, at least in the Mid Atlantic region, despite requiring two full gauge sizes larger wire - 10 instead of 12 for a 20 amp circuit, for example. Dad did a partial rewire of our house in that time period, as he was more or less finishing the attic for my room - 3 bedrooms, four kids, with two of my sisters only a year apart, so they could share a bedroom.
Thanks for the info, Doc. 🫡
The 'problem' is that knob and tube wasn't 'rated' for anything over 10 amps, as the wire tended to overheat... sigh
Some of the early stuff was as small as 16 gauge, so yes, 10 amps would have been the limit.
The house I did most of my work in was rebuilt in the early 1930s, after the original 1910 Craftsman Bungalow was mostly destroyed by a tornado. It had piped gas ceramic heaters, two chimneys - one for a fire place, the second probably for a coal stove heating the connected bedrooms, swinging doors for both interior kitchen doors, and multipane doors between the dining room and the living room. There was also a small detached garage with an attached servant's quarters. The roof deck and interior walls were ship lap true 1 inch yellow pine. The rafters, joists and wall studs were all true 2 inch yellow pine - all hard enough that I had to drill pilot holes to hang pictures!
The wiring I was working with was mostly 12 gauge tube and knob, with some of the 1950s rewiring being Romex 10 gauge 3/G for the dryer, stove, and an air conditioner later mounted in the Dining Room Window.
it's better not to say how the grounds were run for the wall sockets!
And we were only the second family to occupy the home.
Wow! And yes, that old yellow pine was TOUGH!
There's still a fuse box in my shed with plug fuses.
My 1909 house still has knob and tube feeding the upstairs bathroom. I rewired the bathroom during a renovation and had the choice of leave it alone or doing lots of rewiring. I left it alone. The bathroom is updated, the feed is not.