Older house wiring puzzle

Have a client with a house built in the '20s, originally knob and tube wired but (partly) converted to more modren wiring methods. Basement ceiling is exposed and where the majority of the house wiring is. Lots of strange, non-standard and some clearly improper wiring exists there: "flying" splices between K&T wiring and NM or armored cable (no junction box), and one place where someone just ran a single insulated wire (THHN or whatever) as a neutral from one place to another. Plus exposed K&T runs going everywhere, one right next to the hot-water shutoff valve.

So I've figured out pretty much what goes where and how to replace it (mostly with runs of Romex, since it's not an occupied space).

But there's one thing about the old wiring that's puzzling to me. Usually K&T runs are done with pairs of wires (Hot & neutral) running alongside each other, and in most cases that's followed here: a run up into a wall will have a pair of wires going up into the subfloor.

But there are a couple of places where a *single wire* is routed up out of the basement into the house above. In these cases, the wires are all hots. No corresponding single neutral wire anywhere nearby. Presumably the neutral side of the circuit is tied to the neutral of another pair of wires.

This, of course, makes it difficult to map these circuits, since I can only assume that the neutral connection is made to the neutral wire corresponding to the hot wire. That's my operating assumption, anyhow: my plan is to simply replace these single-wire runs with Romex, using only the black wire. (Hmm, wonder if they make 12-1 Romex w/o ground? Probably not.)

Anyone ever seen this situation in an older house?

Reply to
David Nebenzahl
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You need to ring it out and see where that conductor goes. It's probably going to a switch, who's return takes another path. Check outside lights, hall lights, or things like the oil burner , that may have an emergency switch in the main house

Reply to
RBM

I'm pretty sure you can't run a single wire.

"All conductors of the same circuit and, where used, the grounded conductor and all equipment-grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted"

If you google appropriate portions of the code quoted above you can learn more, including the rationale.

Reply to
Mike Paulsen

On 9/10/2009 5:09 PM Mike Paulsen spake thus:

I believe you. However, think about it: the only way to rectify the situation so as to bring it in line with the current code would be to rip out the existing wiring in the walls of the house and replace it.

I can tell you that ain't gonna happen in this case.

What I plan to do will make it safer than it is now and satisfy the client, plus make it possible for them to insulate under their floor (which can't be done now since K&T wiring cannot be embedded in insulation).

By the way, in answer to another respondent, I have figured out where that single hot wire goes: I cut it, and found that most of the lighting in the front part of the house quit working.

Reply to
David Nebenzahl

In the town I went to college in (long before they tore them all down to put up 4plexes for rich yuppie kid students), there were lots of older K&T era houses split up into student slum housing. Most common approach was to disconnect and abandon the K&T in place, and rewire the house with conduit and/or raceway on the walls.

Is this a viable temporary workaround in your situation? A conduit riser in the back of a closet to small subpanels, and then out like a spiderweb into the rooms? Not pretty, but livable, and a lot cheaper than opening walls.

Oh, and on that single wire? By any chance, was the house old enough that it originally had gas lights? I have seen once or twice, a cheapjack conversion, where they used the old gas lines as the return path....

-- aem sends...

Reply to
aemeijers

Typical "ring wiring" In the low current requirements of years gone by it was not uncommon. The first house my folks bought in 1958 only had

2 circuits. All K&T, and the "live" was connected to the fuse at both ends. There had been NO modifications made in over 50 years (house was 85 when we got it) and my dad, being an electrician, rewired EVERYTHING within the first 6 months to a year.
Reply to
clare

On 9/10/2009 7:34 PM snipped-for-privacy@snyder.on.ca spake thus:

Apparently this house has a couple of partial "ring" circuits in addition to more conventional (by U.S. standards) wiring.

Reply to
David Nebenzahl

What you soon learn working on old K&T houses is there is no such thing as "conventional"

Reply to
clare

does the clients homeowners insurance know they have K&T?

The home really needs a complete rewire bringing up to current code

once you muck with this a future fire can see you on the hook for damages and insurtance company can go after you.........

K&T is very obsolete and what of attic insulation? as you said you cant imbed K&T in insulation and the roof is the largest loss of heat in a home......

you say client, are you doing repairs there?

Reply to
bob haller

their insurance, like mine, probably couldn't care less.

Reply to
Steve Barker

GUARANTEED they will if theres a fire. you having been the last to work on the wiring will be on the hook. are you insured? liability if theres a fire? are you a registered electrician?

besides TODAY most insurance companies wouldnt take on new customers with K&T

insurance is risk adverse

Reply to
bob haller

The only links I remember on K&T (originally posted by Phil Munro) are:

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a report to the Illinois Department of Commerce and Community Affairs on adding building insulation around existing K&T wiring. No record of hazard was found in the large number of K&T installations that had insulation added around them. (Larry Seekon, whose comments are quoted, was head electrical inspector in Minneapolis.)

or

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the record of a complaint to the Maine state Bureau of Insurance by a homeowner against an insurance company. The insurance company denied renewal of a policy based on K&T wiring. The insurance company was ordered to renew the policy because the insurance company "provided no justification for its position that knob and tube wiring per se automatically provides grounds for nonrenewal".

In my opinion insurance rejection of K&T is the latest version of redlining.

And if I remember right, the electricians in this newsgroup think K&T is not significantly more hazardous than other wiring methods. If it has been abused it can be a problem, as can other wiring methods.

Reply to
bud--

The only singe-wire runs you *should* have are ground wires added later to an existing ungrounded circuit. I would recommend leaving any sound K&T wiring going to the bedrooms and such alone. Original wiring that was done right and not messed with. The mess that you're talking about, I'd replace it all with new NM cable; abandon in place the stuff that's hidden in the walls and tear out what's exposed in the basement. DO NOT do that black-wire-only thing you are talking about.

Last time I checked (which was in 1995) K&T was an acceptable wiring method in the electrical code, but not for new work. You could still make repairs to old K&T and the NEC gave some details about it.

Maybe you could just cut those single wires and see what goes dead? :-) (Probably switched lights or split outlets.)

Best regards, Bob (not an electrician)

Reply to
zxcvbob

On 9/11/2009 9:27 AM bud-- spake thus:

Thank you very much for those useful links, which are a good antidote to the previous poster's paranoia.

I must say, though, that as comforting as the findings there are (that insulating around K&T wiring poses no dire threat), I won't do it. When it comes to wiring I always like to err on the side of caution.

But yes, the previous poster's shrieks of alarm are unwarranted. Properly done K&T wiring in good condition (as the wiring in this particular house is) is no less safe than modren wiring methods.

Reply to
David Nebenzahl

On 9/11/2009 10:00 AM zxcvbob spake thus:

But I have to if I want to get rid of the K&T runs as the homeowner wants me to. Since I'll be replacing it with NM cable (which is what I proposed--*NOT* just running a single black wire, like the person before me who ran a single white wire several feet for a neutral conductor)--it'll be as safe or safer than what was there before.

I already did that, and I thought I posted that here. When I cut the single wire, all the lights in the front of the house--living room and front porch--went out. No outlets, just lights. So I know what's on that circuit. I just don't know exactly where neutral wire for that circuit comes out. But since it'll all be replaced by NM anyhow, doesn't really matter. I was hoping someone could comment authoritatively on that anomaly (the single-wire feeds), but I guess not.

Reply to
David Nebenzahl

David Nebenzahl wrote: ...

Indeed... :(

But, it's his personal vendetta it appears despite chastisement and demonstration that he's simply just generally wrong on numerous previous occasions as well...

--

Reply to
dpb

On 9/11/2009 10:48 AM dpb spake thus:

Plus he's one of the few posters here with the annoying habit of never quoting previous replies (small point, but not in his favor).

I will say that I think exercising due caution when doing electrical work is important. I cringe when I see the numerous news reports of houses burning down, just wondering whether it was an electrical fire that was responsible. I don't *ever* want to be the cause of such a fire.

But that doesn't mean one has to be a total Cassandra about it either ...

Reply to
David Nebenzahl

That's a fact jack. And covering it with insulation does nothing to it either. Well, it might keep the mice and squirrels off it. LOL! As for being a fire hazard, well a 14 ga wire on a 15a breaker is not going to get hot, and it is almost always at least 10" away from it's partner wire, so there's not much chance of a short, so I would go so far as to say the K&T wiring methods in many ways are much safer than the practices we use today.

Reply to
Steve Barker

I think the phrase "once you muck with this" is the key. It doesn't matter whether you (in theory) do or do not make it any worse than it is now. Once you touch it you may be held responsible for it.

Does local code/law require you to be a licensed electrician to do this work? Does your liability insurance cover electrical work you perform? Does the locale require permits? Will the owner's policy cover them if non-permitted or non-inspected work results in damage?

Reply to
Mike Paulsen

To trace the mystery wire get one of those AC circuit tester pen gizmos. If I recall these will sniff out an active circuit under the plaster. So what you do is kill all circuits except the mystery one and trace the wire runs.

Reply to
Roger Shoaf

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