I've seen old houses where all circuits enter the breaker box as cables, but some rooms still have knob-and-tube wiring. (A homeowner who needed to upgrade wiring for his kitchen may have found the old wiring adequate in a bedroom.)
That leads to a question that didn't occur to me before. Was there a proper way to connect K & T to a cable?
On 5/31/2010 1:50 PM J Burns spake thus:
There was, and I *think*(TM)(R) it simply involved making splices using approved methods (like Western Union splices) and covering them with insulating tape. I don't think such connections had to be inside a junction box, as they would today.
But I could be wrong.
Originally, the K&T would have entered the fuse panel through screw in ceramic insulators. When that panel was replaced they probably ran a piece of BX cable to a junction box, and ran the K&T insulators into knockouts in the J box, then either spliced with wire nuts or solder depending upon when it was done. Here is a picture of an old K&T fuse box. Notice the fused neutrals:
When I was 12 years old we lived in an old (1900) house. It had K & T wiring and screw fuses. One day a damper motor on the furnace overheated and set the ceiling on fire. I called fire department. Parents were both at work trying to exist in the depression. Fire Chief asked where the fuse box was. I showed him and which fuse was on that circuit. He said here is the problem, there is a 15 amp fuse and it should have been a 30 amp. Hello... I knew better than that. Later years I worked on trouble shooting for a utility company. Had a call on an old house that dining room light would not work. Found screw fuse bad. Replaced fuse to check and it blew. The owner said the room had just been painted and painter remove the overhead fixture but he replaced it when paint was dry. I pulled the fixture and found all 4 wires, hot and ground twisted together with one wire nut. Corrected that. On fuse panels on all calls I always removed all fuses to check for any arching on center contact. On this house one fuse had an Indian head penny under it. Lucky it was not the circuit that the fixture was on. Who knows how long that had been there. WW
The 30 amp fuse on the 15 amp circuit, and the penny under the fuse, may not have been exactly improper. Those old panels had fuses on the neutrals, which can be very dangerous. Ultimately those fuses were replaced with solid brass fuse plugs, but I'm sure penny's worked just as well.
>*You are better off not touching the K&T wiring. If it works, leave it alone. If you want to add outlets run new home runs.
Thanks. Comments by others are interesting, too.
In the 1980s, my parents moved into a house where they wanted grounded outlets, more outlets, and fluorescent lights. Cables went from the breaker box to junction boxes in the attic, but much of the lighting was on K&T.
Instead of making connections to K&T, I was removing it. I wasn't aware that the insulation was unreliable, so I didn't think about how the electrician who had installed the junction boxes had made safe connections to existing K&T.
Hmmm. So one of the left "feeders" is hot, and the other neutral, and the right-hand wires are pairs of hots and neutral, all fused? That's interesting. I'll assume that this is a property you worked on and that this is what you found.
Just looking at the picture, I'd have guessed that two feeders were two hot legs of a 240/120 supply, feeding three pairs of fuses, with the fused wires going out on the right. The other side of the circuits would likely run back to the service entrance, unfused, and go nowhere near the box.
What really stands out for me, whichever it is, is that each of the left-hand wires are each feeding (or being fed by) three fused legs but aren't noticeably heavier gauge. If they're feeding three 20-A circuits (orange fuses) they ought to be, by our standards, 8 ga or heavier. Was this in fact the case?
Chip C Toronto
neutrals:
Just looking at the picture, I'd have guessed that two feeders were two hot legs of a 240/120 supply, feeding three pairs of fuses, with the fused wires going out on the right. The other side of the circuits would likely run back to the service entrance, unfused, and go nowhere near the box.
What really stands out for me, whichever it is, is that each of the left-hand wires are each feeding (or being fed by) three fused legs but aren't noticeably heavier gauge. If they're feeding three 20-A circuits (orange fuses) they ought to be, by our standards, 8 ga or heavier. Was this in fact the case?
Chip C Toronto
The two wires on the left are feeding the panel. They're #10 conductors, they're sleeved through loom, one is neutral and one is hot. The six wires on the right are #14 conductors sleeved through loom as well. Each circuit has a fuse on both hot and neutral. All of those fused neutrals should have been corrected with solid brass fuse plugs at some later date. The entire house was fed by a 30 amp 120 volt service. This is the service panel. It and the main disconnect panel, which I'll link to are located in the attic, which was also very typical.
CALL some home owner insurance companies ASK if they will insure a new customer with K&T. Please report back here your findings.
if they wouldnt sell new policies you might as well replace ALL the K&T since its impossible to get a mortage without homeowners insurance
neutrals:
neutrals:
It most certainly is. Both boxes are lined with 1/4" asbestos panels
>On 6/1/2010 2:09 PM RBM spake thus:
My friend has exactly the same setup in his ca.-1920 house: 4 pairs of fuses, hot & neutral, inside an asbestos-lined wooden box.
He solved the problem neatly by simply overfusing the neutrals: I think he has 30 amp fuses on that side, and he put 15-amp circuit breaker replacement fuses on the hot side. The lower-current breakers will always trip before the higher-current fuses blow.
Geez my grandfather had a box like that in his workshop but his was slate lined.
Jimmie
Why should I do that? Do you think no homes with K&T are insured? I've gotten policies from three companies for homes with K&T.
Cable became popular in the 1940s to save labor, but I'll bet K&T was safer.
I believe the NEC requires an inspection after loose insulation is put into a space with K&T. CA and WA dropped that requirement because not a single fire had resulted from insulation on K&T.
I'm afraid you might have just pushed Hallerb over the edge
Insurance companies don't generally ask what kind of wiring you have.
I have friends wqho attempted to sell homes with K&T no buyers could get a new homeowners policy. one person never did sell.
my best friend found he could get a big savings by combining homeowners with car insurance.
State Farm refused to sell him a policy. Not only over K&T but his highly detoriated and patched front steps. the steps are different heights thanks to the patching.
hey its your money and your hassle when you cant get a buyer. so enjoy your K&T.
incidently several years ago my buddy with K&T smeled something hot, and found a connection frying in the cieling.
Yes, and i've got 4 rentals with K&T in them. I even asked my agent about it. He said they could care less. It's not a hazard. And yes, there's blown cellulose on top of it in the attic and down the walls.
I've NEVER had one ask. I had to ask them. And they said no problem.
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