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KingsX · Feb 20, 2009, 04:45 PM

My house has knob and tube, with only two circuits. One circuit runs all the lights on the main floor (bungalow). The second one is for all the outlets on the main floor, plus all the lights in the basement (maybe 5 fixtures), plus one only outlet in the basement.

When I moved in, there was two thirty amp fuses in those two circuits, which is obviously wrong and dangerous. I switched them back to 15 amp fuses each. Now I have to be careful not to run the microwave and the coffee machine at the same time, but shockingly, its working out.

My house was built in 1921 and I couldn't tell you when those thirty amp fuses went in, or if they have been swapped through time, or what. So my concern is, being that this wire is old, could the constant extra heat over that time have degraded the wire so bad, that even now that I have 15 amp fuses in there, I have a serious fire risk? I have a 16 month old daughter and another on the way, and I all of a sudden got very paranoid. I plan on replacing the electrical, but its going to take some time. What do you guys think?

EPMiller · Feb 20, 2009, 04:59 PM

If the K&T wiring was severely overloaded, it could be degraded. However, correctly done K&T is pretty safe if you don't continue to overload it. Don't change any devices or move any wires if you can help it. Flexing could cause insulation to fall off and then you have to go to shrink tubing and all that to save it. Possibly your house is wired with #12 wire which would be rated at 20 amps, which would be better than #14, but don't go upping the fuse rating without being CERTAIN it ALL is #12 on a circuit. Don't lose any sleep, but get it changed when you can afford it. I've lived with it almost all my life.

KingsX · Feb 20, 2009, 05:02 PM

We've managed with 15 amp circuits, so I don't see a point anyway in changing it. We do have a sub panel with updated wiring for the stove, fridge, some more outlets in the basement, and garage etc. So thankfully I don't have to worry about those. But, still all bedroom outlets, living room etc are on that original k&t. I did replace the outlet in my daughters room with a gfci. And I've had to replace the odd light switch, but didn't see any crumbling or damage inside the box.

EPMiller · Feb 20, 2009, 05:34 PM

If you didn't see any problems in device boxes, I doubt that there's too much damage elsewhere. Most junctions on the actual wires are soldered, so they are pretty immune from heating if done correctly. And since your heavy draw appliances are on modern wiring, you should be safe with the correct fuses.

Sleep well.

EPM