Return to Answer

added 44 characters in body

Source Link

edited Nov 16, 2018 at 21:07

The "air gap" theory is a myth. The size of wire used for K&T is the same as for modern wire, plus the joints are better.

The real issues are that most knob and tube circuits are undersized for the modern need, so many peoplehomeowners (and some electricians) upsized the fuses. Rest assured if you have 12 gauge wire and a 20 amp fuse, you're fine. If you have 14 gauge wire and a 15 amp fuse you're fine.

From Home Energy Magazine 'Knob and Tube Not a Fire Hazard':

Legislation was enacted in Washington state to allow insulating over knob-and-tube wiring per Bonneville Power Administration (BPA) specifications. This resulted because there were no documented cases of a fire being caused by knob-and-tube wiring, whether insulation covered it or not.

K&T has huge advantages when it comes to driven staples and nails, and fire. It has theoretical downsides if blown in insulation gets wet. K&T wire insulation varies in quality from great to really bad -- but fortunately the K&T system does not require wire insulation.

The "air gap" theory is a myth. The size of wire used for K&T is the same as for modern wire, plus the joints are better.

The real issues are that most knob and tube are undersized for the need, so many people upsized the fuses. Rest assured if you have 12 gauge wire and a 20 amp fuse, you're fine. If you have 14 gauge wire and a 15 amp fuse you're fine.

From Home Energy Magazine 'Knob and Tube Not a Fire Hazard':

Legislation was enacted in Washington state to allow insulating over knob-and-tube wiring per Bonneville Power Administration (BPA) specifications. This resulted because there were no documented cases of a fire being caused by knob-and-tube wiring, whether insulation covered it or not.

The "air gap" theory is a myth. The size of wire used for K&T is the same as for modern wire, plus the joints are better.

The real issues are that most knob and tube circuits are undersized for the modern need, so many homeowners (and some electricians) upsized the fuses. Rest assured if you have 12 gauge wire and a 20 amp fuse, you're fine. If you have 14 gauge wire and a 15 amp fuse you're fine.

From Home Energy Magazine 'Knob and Tube Not a Fire Hazard':

Legislation was enacted in Washington state to allow insulating over knob-and-tube wiring per Bonneville Power Administration (BPA) specifications. This resulted because there were no documented cases of a fire being caused by knob-and-tube wiring, whether insulation covered it or not.

Source Link

created Nov 16, 2018 at 21:01

Bryce

The "air gap" theory is a myth. The size of wire used for K&T is the same as for modern wire, plus the joints are better.

From Home Energy Magazine 'Knob and Tube Not a Fire Hazard':

Legislation was enacted in Washington state to allow insulating over knob-and-tube wiring per Bonneville Power Administration (BPA) specifications. This resulted because there were no documented cases of a fire being caused by knob-and-tube wiring, whether insulation covered it or not.