Panel upgrade on house with K&T wiring...

1278 Views 4 Replies 3 Participants Last post by AllanJ, Dec 19, 2012

theatretch85

Discussion Starter · Dec 18, 2012

What's generally the best practice when upgrading a fuse panel in a house that has Knob and Tube wiring to a circuit breaker panel? Do all the knob and tube circuits need to be upgraded and replaced with modern wiring or can they be left alone and connected to 15 amp circuit breakers in the new panel?

Or would the best option be to leave the fuse box in place for the older circuits and feed the fuse box from a circuit out of the new panel?

Several of the circuits appear to have 30 amp fuses on them (when they should probably have the adapter screwed in to limit the fuse size).

Also, currently the main panel, a sub panel, and the meter are all located in the basement on an interior wall, right behind the water heater (obstructed access). The UN-fused meter cable runs through conduit from the outside to the meter inside approx 5-6 feet, of course with the meter and the panels being blocked, the obvious solution here would be to move it to a new location.

I would of course involve the power company regarding moving the meter (and upgrading it) once a new location for the main panel has been determined, but trying to get an idea of the size of the project before diving in head first.

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joed

· #2 · Dec 18, 2012

Sounds like the circuits are overloaded. In most places you are not required to update wiring when a panel is replaced. I would proceed with the panel replacement.
If money and time permits also update the K&T but there is no reason it can't be left for later project. You may find issues when those circuits are put back on 15 amp fuses however.

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AllanJ

· #3 · Dec 18, 2012 (Edited)

It is not necessary to upgrade the knob and tube circuits forthwith or on any time schedule, except to satisfy an insurance company or a prospective buyer of the house.

(Nothing may be appended to the existing K&T circuits; you would need to run new circuits for new lights, additional receptacles, etc.)

Immediately replace all the 20, 25, and 30 amp fuses with 15 amp fuses for circuits containing 14 gauge wiring. You can use 20 amp fuses for circuits with all 12 or larger gauge wiring and with regular receptacles and/or light fixtures.

Usually the easiest method is to leave the old fuse panel in place and run a feed to a double wide double breaker with handles tied together in the new panel. (Single breaker if the old panel is so old as not to have 240 volts.)

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theatretch85

Discussion Starter · #4 · Dec 19, 2012

I have seen in at least two places, existing wiring (appears to be aluminum) has been extended with newer copper wiring and there does not appear to be any anti-oxidant or even proper connectors for the purpose. I have no intentions of extending the existing circuits (will certainly be looking into fixing the two additions) but will be looking at fixing the circuits after the panel upgrade and as time/money allow.

I wondered if there would be issues with the 30amp to 15amp downgrade on the circuit protection; I think the easiest thing might be to map out each fuse and see what it controls and then take off some of the high load items and re-wire those parts first, leaving the remainder of the circuit on a 15 amp fuse or breaker.

Ideally would like to remove the old fuse panel as replacing fuses can be a pain and the fact it is blocked by the water heater making it somewhat difficult to get to.

Thanks for the information, knowing now that the old circuits don't need to be upgraded due to a panel replacement is a big help in the matter of pushing this project forward.

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AllanJ

· #5 · Dec 19, 2012 (Edited)

The wiring is probably tinned copper, which is a little easier to solder than plain copper, and does not have the problems of aluminum.

You will have issues (danger of fire) if you do not downgrade all the fuses to 15 amps (20 amp for circuits with all wiring 12 gauge or fatter).

When knob and tube wiring has soldered joints, it is actually very safe provided that the wires are not so slack as to be able to droop and touch each other and you do not overload the circuits.

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