Knob-and-tube
Replacing knob-and-tube wiring in Philadelphia rowhouses
Replaced, not spliced: new cable from the panel to every box.
Knob-and-tube was the wiring in many Philadelphia houses built before about 1930. It has no ground, and over a century it has been cut into, covered with insulation and added to. We trace it, show you where it is, and replace it room by room.
Same-week appointments
Plain-language explanations
How to tell what you have
Where to look in your own house
In the attic
Single wires on porcelain knobs and tubes through the joists.
In the basement
Cloth-covered cable stapled to the underside of the floor.
At the outlets
Two slots and no round hole for a ground.
At the panel
A fuse box, or a breaker panel with a few circuits and no room for more.
What the visit includes
From the survey to the last patch
- 01
Trace
We follow each circuit on the survey sheet and mark what is live and what isn't.
- 02
Plan
In writing, with the order of rooms.
- 03
Replace
New cable, boxes and grounded outlets. Old conductors are removed where we can reach them.
- 04
Inspect
The city inspector looks at it before the walls are patched.
Questions about knob-and-tube
Is knob-and-tube wiring dangerous?
Not by itself. It becomes a problem when it has been cut into, covered with insulation, overloaded or spliced to newer cable. We look at what you have and tell you what we found, room by room.
Will my insurer care about my wiring?
Some insurers do, especially with knob-and-tube or a fuse box. Ask yours. We can give you the written survey sheet and, afterward, the record of what was replaced. We don't promise what any insurer will do.
Do I have to move out?
Usually not. Power is off to the circuits we are working on, and we plan the order of rooms with you so you can keep a kitchen and a bathroom running. Some houses need a day with the power off at the panel, and we tell you which day ahead of time.
Find out what you have
The survey sheet shows every circuit and what is on it.