Home & Garden Columns
I confess to some iconoclastic tendencies. I’m probably more geek than rebel but I certainly don’t like to run with the pack. One way in which this is true is that I’m a big fan of antique wiring. It might seem obvious that very old wiring systems are inherently dangerous but it ain’t necessarily the case. Some of these are in great shape and can serve your need handsomely and some are either inherently inadequate by design or have been ruined by any of the armies of despoilers that roam the country.
If you’re buying or living in a 50- to 100-year-old home, you might want to know a little more about how these sysems work and what they look like, so let’s take a look at what’s good about these and what’s not and when and how to make this call.
I was out inspecting with a bright young homebuyer named Neil last week when we got to the roof and I noticed the main electrical service drop. Neil had told me that he had done a little wiring and I like to play games so I asked him what he noticed about the twisted set of fat wires that swung in from the street to grasp the house along one side of a front dormer. He looked and wasn’t sure.
I asked him to count the wires and then he got it. There were only two of these big wires, unlike the three that typically come to a modern house. This was all I needed to know to say that he would be needing a major electrical upgrade.
Now, there is plenty I still had to learn but what I knew at that point was that the house was only receiving 120 volts from the street because there was only a single hot (or energized) wire as well as a single netural wire. Modern systems, some going all the way back to the 1920s but generally around 1940, have two hot wires and one neutral wire or a three-wire service drop.
The main electrical panel was also quite a sight and I got to see Neil’s eyes get really big in response. It was found at the very front of the narrow crawlspace just behind a slatted, wooden, ventilation grill behind the camelias at the front of the house. The grill had to be pulled out to see it and when we removed the grill, this is what we saw:
A wooden board had been nailed to a pair of slender boards that attached to the floor joist so that the board hung down below the floor and faced forward to the crawlspace opening much like a control panel. Screwed on to the panel were several separate parts, mostly made of beautiful highly-glazed porcelain.
First was a fuse mount with just two fuses. These were the main fuses and were rated at 30 amperes or amps, a measurement of power; and was probably about right given the wire size, which determines the maximum safe current levels, and fuses (or breakers) should be set according to this. The wires from the roof had run down to these fuse mounts and, after running through these little safety devices, ran, by exposed, but insulated wires, to an ancient electrical meter that was hung on this board. The lettering on the meter clearly showed its age, which was about 85 years old.
The style of having visible wires between all these components is one signature of this as, essentially, a prototype. A system in early development.
After traveling through the meter, the wires carried the power to several more exposed porcelain fuse mounts, also screwed onto this wooden board and then onward to the rest of the house.
Oops. I forgot one thing. There was a switch. An open knife switch was installed between the first pair of fuses and the meter. This was one of those Dr. Frankenstein switches that has a wooden handle and two long blades that hinge upward and then snug into a pair of prongs to close the circuit. Unlike modern switches, this one has lots of bare metal parts that, if touched, can shock or kill and, like many electrical devices of this time, was forsaken, in favor of safer designs in the years that followed. Nevertheless, there it stood in all its science-fiction glory for Neil to scratch his head at.
One important notion to get about this system is that it is fused on both sides of the circuit. That is, the hot wires and the neutral wires both travel through fuses. This means that there were twice as many fuses as circuits. When we run our neutral wires through a fuse, which we never do today, having arrested the method in 1928 (80 years ago!), we set up a condition in which a neutral fuse might blow from excessive current, leaving power running all the way though a circuit (and a lamp or a TV or whatever) with no way to get home to the earth. This means that the device (TV, lamp, microwave) doesn’t come on and the circuit appears to be dead. This is bad for multiple reasons but, in my never-humble opinon, the most important is that one might start to fiddle with the equipment, not realize that it’s still energized, and get shocked. Also, when we are the only viable path to ground, shocks can be much worse. This is why I will always recommend that any fused-neutral condition be eliminated in favor of equpiment that is in constant contact the the earth (grounded).
The board under the house had four fuse holders on the outgoing side, and, as noted above, these were twice the number of circuits. So, this means that there were only two circuits feeding the house’s outlets and lights.
Now, this is a big issue. For any of you who remember growing up with fuse boxes, you might recall the common syndrome in which one fuse in the house seemed to bear the brunt of the electrical workload and would perenially blow at exactly the wrong time (Thankgiving. Twelve people in the house. First time Cousin Birdie has deigned to come to OUR house). That’s what we’re looking at for this entire house because two circuits is far too little for what will, inevitably, be run off of this system.
The truth is that people don’t tailor their electrical usage to the capacity of the system. They just plug things in, which is natural. If there are only one or two outlets in a room, they get those funny outlet covers that turn two outlets into four or six. Then they use a few extension cords to reach all the parts of the room and, voila, everything plugs in. End of story, right?
What happens when we overburden a system like this is that the wires can get much hotter than they should and, at the most vulnerable point, hidden somewhere in a wall where Uncle Richie stuffed in some newspaper to patch a hole, a fire begins. You know the rest.
Interestingly, many of the houses that have these wiring conditions also lack a compentent source of heat. This results in the use of electric heaters, devices that draw more power than just about anything else we might plug in and, in turn, fires. Oddly, this means that one of the best things any home owner can do for their fire safety is to fix (or replace) the furnace!
In short, (no pun intended) what many houses are begging for is a system of wider distribution; of many circuits, not just a few. A system of many circuits and many fuses (or breakers) is inherently safer because each part of it is far less challenged than the two at Neil’s house.
I guess I didn’t get to much of what I like about our early knob and tube systems but trust me, there is a lot to like and we’ll save that for another day.
Neil will be getting a lot of new wiring, I’m quite sure and I’ll bet he’ll do a lot of the work himself (with a bit of prudent professional oversight).
If you have an older house and the wiring hasn’t been looked at in a while, it might be a good idea. Maybe, that way you can avoid any unpleasant current events.
Sorry, I couldn’t help myself.