Sometimes it seems like half the people I run into are electricians, and the other half are kin to an electrician. Of course, the local definition of "electrician" is just about as loose as the local definition of "songwriter." In either craft, anybody who ever thought about the work for five minutes feels free to claim the title; and the good ones are hard to find.
In the course of a day's home-inspection work, I'm likely to get into an argument about wiring, especially knob-and-tube wiring. For the few folks who aren't electricians, let me explain knob-and-tube: It dates back to the earliest days of residential wiring, around the turn of the century, and it was common until the 1930s. Each circuit has two wires (a hot and a neutral). The individual wires are anchored to the house framing by way of little porcelain knobs. Where the wires pass through beams or studs, they're run through little porcelain tubes. Throughout most of the run, the hot and neutral wires are kept about a foot apart. The wires only get close together where they go into a fixture, a switch, or a receptacle. The wire itself is wrapped with a rubber-and-cloth insulation, which is called loom.
Back when this stuff was in common use, a house would have a 30- or 60-amp electrical service-just enough for a few lights and maybe a radio. These were the days of iceboxes, wood or gas stoves, coal heat, and no air-conditioning. Wiring houses was a new trade, with hardly any rules.
The first house-wiring rules appeared around the turn of the century, when Terrell Croft wrote the American Electrician's Handbook. According to Redwood Kardon, a consultant at the CodeCheck Web site (www.codecheck.com), Croft's books defined early wiring practice. One of Croft's rules was that knob-and-tube wiring should always be run through-never over-the house framing. The problem with running wiring over the framing is that it can get bumped, snagged, and damaged. According to Kardon, wiring run over framing (think guitar strings stretched across the top of the guitar neck) is a sign of amateur, cobbled-together work, and it never conformed to any electrical code.
Wouldn't you know it: Every knob-and-tube installation I've seen is run in the bootleg, guitar-string mode. Not only that, but the rubber-and-cloth insulation is usually brittle and crumbling, leaving little patches of bare naked hot wires exposed. In basements (and a few tall attics), the wires often attach to exposed screws on the light fixtures. The screws are hot. Touch 'em and die. All the knob-and-tube installations I've ever seen have been mangled by a parade of handymen, desperate homeowners, and unskilled tradesfolk. Even if old knob-and-tube wiring were in mint condition, it would still be an obsolete, non-grounded system, not really suitable for today's appliances, gizmos, and gadgets.
But even with all that, there are plenty of people-including a lot of electricians, and even a few of my home-inspection colleagues-who'll tell you knob-and-tube wiring is just fine.
For instance, several months back, my able associate and I saw a house that had knob-and-tube wiring run through the attic and through the attic insulation. Covering knob-and-tube with insulation is a known fire hazard, and it's specifically condemned in the National Electrical Code, in Section 324-4, to be exact.
We explained the fire hazard and recommended that the wiring be removed. That night, the seller's electrician called. He proceeded to tell me that knob-and-tube is "still legal." (Technically, this is true.) He told me that there was no reason to replace the wiring. Of course, he didn't know that I was looking at my caller-ID box, which told me he was calling from his real job, at a fast-food joint. (OK, I know, theoretically he could've been there wiring the building. But I paid close attention to the background noises, and I'm pretty sure this guy was working the drive-through window.)
So if you've got old knob-and-tube wiring in your house, I say rip it out as soon as you get a chance. If an electrician-or anybody else-tells you it's OK, ask him to put that in writing, on his company's stationery, over the company president's signature.