letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
Knob and tube OCP
- Thread starter brother
- Start date
- Status
zbang
Senior Member
- Location
- Roughly 5346 miles from Earls Court
We were just poking fun at old times when folks used to violate the code by putting dimes and pennies or bend the outer edge of the fuse over the tip to bypass it. Some found that "disturbing" as if it was some type of "how to" post which it wasn't.
JAP>
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
I was in an old foundry in Philly and instead of span wires for the bridge cranes they used steel angle on insulators.
rambojoe
Senior Member
- Location
- phoenix az
- Occupation
- Wireman
Its hard to believe that there is still more than a small amount of knob and tube about... and fuses.
I hate to say i classify homeowners/landlords who just dont care about updating things like old wiring but being an electrician, i do. Its getting to a point where those old conductors and loom sleeves at outlets are getting scary.
I understand if it works it works but that rubber crap is getting long in the tooth...
I hate to say i classify homeowners/landlords who just dont care about updating things like old wiring but being an electrician, i do. Its getting to a point where those old conductors and loom sleeves at outlets are getting scary.
I understand if it works it works but that rubber crap is getting long in the tooth...
But, how would the average home owner ever know that?
All they see is the outlets, not what's in the walls.
As long as the outlets work, why replace it?
My lawnmower may be old and wore out also, but, I'm not replacing it until it stops cutting grass.
JAP>
rambojoe
Senior Member
- Location
- phoenix az
- Occupation
- Wireman
What do you mean by us?
We don't randomly get called unless someone is having issues.
JAP>
I'm just saying the average home owner has no reason to call an electrician if everything is working as it should be.
It's only when they have an issue and we arrive to find the reasoning for the issues is when the replacement conversation comes up.
And, that's usually a very expensive conversation at that.
Very few would take on the expense of replacement if they weren't having troubles to begin with.
JAP>
It's only when they have an issue and we arrive to find the reasoning for the issues is when the replacement conversation comes up.
And, that's usually a very expensive conversation at that.
Very few would take on the expense of replacement if they weren't having troubles to begin with.
JAP>
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
I never see it anymore, but I'm in an industrial setting for the most part. From what I remember what I have seen that was undisturbed was fine. But 90% of it was hacked up by some home remodeler in like the 60's or 70's. Sometimes even spliced into with aluminum NM cable.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
You realize you're talking about tearing out walls and ceilings, right? Wiring doesn't usually get fully replaced until there's a remodel. My own house most of it didn't get removed (or decommissioned) until we did a remodel, and there's still three switch legs that didn't get replaced because those walls weren't redone.
I see a lot more K&T than I see fuses. But I still see fuses now and then, often some little 'subpanel' with four fuses in a closet that's now fed by a breaker.
And yes some owners don't care, or know. And some can't afford to do anything about it.
zbang
Senior Member
- Location
- Roughly 5346 miles from Earls Court
Single (usually) insulated conductors supported by porcelain insulators (knobs) or cleats and protected by porcelain tubes where it passes through holes (usually in wood). The splices are soldered and taped to insulate. Use for building wiring before cable became common.
kwired
Electron manager
- Location
- NE Nebraska
If you ever been around corner grounded systems you might. Sometimes used as a slug for the grounded conductor in fused disconnects, which is sort of ok as you aren't supposed to use a fuse in a grounded conductor. Problem is when a non qualified get ahold of it and thinks it might be ok to replace that fuse that keeps blowing with the slug.
drcampbell
Senior Member
- Location
- The Motor City, Michigan USA
- Occupation
- Registered Professional Engineer
Prior to about 1940, wire was usually often insulated with natural rubber and wrapped with varnished cotton.
Because it wasn't very durable, it was strung in open air and protected/supported with ceramics.
When you find it today, the natural rubber has usually become so brittle that it promptly turns to dust when you touch it, if the varmints and insects haven't chewed through it first. The ceramics keep it safe (almost) even if the insulation disappears entirely and the bare copper is exposed. Problems occur at the terminations (the cut end of the cotton sleeve usually unravels) or when something changes, such as the aforementioned thermal insulation being retrofitted into the attic by a Bigfoot crew, or adding devices for which the amperage capacity doesn't exist.
To further confound things, American practice was to make 10, 15, 20, and 30-amp fuses all in the same interchangeable package. If the fuse kept blowing because you added devices, it was a trivial matter to put a higher-capacity fuse in its place.
(Canadians were a little smarter than this, making the diameter of the button on the base of their screw-in fuses proportional to the amperage rating, and putting non-metallic rejection washers into the fuseholders to make it impossible to put in a higher-capacity fuse)
Knob-and-tube wiring - Wikipedia
ptonsparky
Tom
- Occupation
- EC - retired
Hard cu pipe vs the soft tubbing is the preferred ag engineered solution.
For that we usually use 11kV or greater.
- Status