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How to Replace Knob and Tube Wiring With Romex

My 100-year-old house had knob and tube wiring

In early 2018, I purchased a house "as is". It was a house sold through an estate and it had been lived in by three generations of one family. Both the good and the bad news was that it had not been updated. My biggest concern was that it had knob and tube wiring. Everywhere.

knob and tube wiring and an old push button switch.

The same wiring that always seems to be a big issue in many HGTV shows (Property Brothers, Love it or List it). In these HGTV shows, they always seemed surprised to find knob and tube wiring, but I sure wasn't. The sellers, including the real estate agent, were very upfront about some of the issues of the house. And then there was the 64-page inspection report ...

All the light switches looked like this.
old push button light switches

And there were a few DIY projects like the one behind the fridge.  I'm assuming they were DIY projects!    I'm sure an electrician wouldn't use a power bar to plug-in electrical appliances!

DIY electrical wiring behind my fridge

It sure looked a lot better once my electrician installed a proper electrical outlet!
fixed wiring with new outlet
I guess you can see why replacing all the electrical was a huge priority for me!

Why replacing knob and tube wiring system was a priority.

There were quite a few reasons.

  1. I was surprised my homeowner's insurance company didn't have an issue with the wiring.  I was told that although they didn't have an issue at that point, there was a potential insurance issue later.
  2. Did you know knob and tube wiring doesn't have a ground wire?  So, all those appliances etc., are not grounded when they are plugged in.  Just because you can plug in a plug with three prongs that doesn't always mean that outlet is grounded - it just looks like it is.  Seeing the three-prong outlets that weren't grounded made me not trust what was there.  The technical term is there is an absence of an electrical grounding conductor.
  3. There was some visible damage caused by rodents in my attic.  The live wires were touching the flammable insulation.  I would never have been able to sleep knowing my house had wiring that in certain areas was a fire hazard!
  4. My home inspector told me my knob and tube was properly installed and most of it was safe.  But, I needed to get a licensed electrician to do a thorough electrical inspection of all of it (some was in the ceiling and some in the walls!).
  5. When I purchased my home, I was happy to note it didn't have fuses in the electrical panel.  However, even though there were circuit breakers, it was felt that with modern use, the panel should be upgraded.
  6. There were a number of ground fault circuit interrupter (GFCI) electrical receptacles in my house.  Those are the outlets that can individually be tripped and have the little reset button on each outlet.   The number of those in my home made me uncomfortable.  Especially when some of them made buzzing sounds or did not reset.
  7. The electrical receptacles (outlets) in the bathrooms and kitchen were not grounded.   If I had chosen to keep the existing knob and tube wiring, they all would have had to be changed to GGFCI receptacles.

But, back to the knob and tube. This is what they look like.  The knob is on the left and then there are three tubes.
knob and tube for aluminum wiring plus sample wire insulation.

The porcelain knobs were nailed into the wood so that they could hold the wires away from the wood. This was so the aluminum wire would be exposed to air so it wouldn't get hot and start a fire. The knobs made sure the wires were kept safely in the hollow spaces of walls and did not touch anything flammable.

knob with aluminum wiring between the walls

In the picture below, take a look below the knob, and you will see how the tube is used.   The aluminum electrical wire is threaded through the 2 x 4 and the tube insulates the wood from making contact with the wire.

image of knob and tube with aluminum wiring

I had my electricians pull out all the old k&t wiring even though it was disconnected.  I didn't want anyone buying the house (years and years from now) seeing it and thinking there was still live knob and tube.  Sadly, I can't find the box where I had all the knob and tube stored!

a box with knob and tube components of knob and tube wiring

Rewiring the house was my number one priority when I purchased this house.  I even ended up firing my first electrician because he didn't seem to feel it was as important as I did.

I have a walk-up attic.  One day, when I win the lottery, this is going to be a really fun hang out room.  But not now.

There was a rough wooden floor in the attic but it was removed so that the electricians could replace the wiring in the second story.  I had the choice of taking down the second story ceiling or the attic floor.  So the floor went.   That's when we discovered that the insulation was not good and the wiring was touching it.

knob and tube wiring running through insulation between floorboards

The wiring had also been nibbled on by, I believe, some mice.  So there was exposed wire touching the flammable insulation.  So yes, I was glad I decided to rewire the whole house.  It gave me peace of mind knowing I made the right decision to replace everything especially once I saw what I could have potentially have left in the ceilings.

One of the most exciting things I did was remove a kitchen wall when I did a total kitchen gut and renovation.  If you want to see those details, take a look at my post called, My Kitchen Renovation, I bought a house without a kitchen!

The kitchen had flooded two weeks before someone else was supposed to buy it.  They backed out of the closing and I was able to buy it.

The dining room looked like this!  Everything from the kitchen, laundry room, and a powder room was in the dining room because of the flood in the kitchen.

See the wall on the left side of the picture below?  That's the wall we took out.

The dining room with the contents of the kitchen, powder room and laundry room.

Here's the wall, down to the studs and the original electrical and plumbing.  Three generations of women in one family stared at a wall when they did the dishes.  I had the kitchen sink moved to under the kitchen window.  It wasn't cheap to do, but that's where it was supposed to be!

Looking through the wall from the kitchen to the dining room.

And when the rest of the wall was taken down, the original electrical wires were the last thing removed.

A removed wall with a new header beam.

This was a major remodel.  Do you see the new header in the picture above?  I know way more about the internal structure of my home than most people ever would!  Plus I have pictures!

The picture below is my favorite picture of the remodel.  It's a closeup of the light switches for the kitchen and dining room.  And they were still functioning at the time!

old knob and tube switch dangling where old wall was

Fortunately for me, I was able to buy new, safe reproductions of the push button switches and the inner workings of these lights.  My electrician insisted I replace the old switches because he didn't feel the old ones were safe.  But the new ones that were installed on the main floor look the same!  It was a splurge that I was glad I made.

Replacing the electrical in a house is a ton of work.  I also added a few outlets and they had to cut out big holes in the walls so they could figure out what was behind the lathe and plaster so they could put the outlets in the appropriate places.

I sure had a high drywalling bill as part of this project!

new electrical outlet installed

wall cut out for new electrial wiring

I'm so thankful that I had a great drywalling crew.  They did an amazing job patching up these holes.  You would never know there were holes like this all over my house.  Like over 40 of them!

It was a huge expense rewiring the house but it was the right time to do it.

I also had to gut the one full bathroom in the house and then added one right behind it.  That wall was taken down to allow the electricians and plumbers to do what they needed to do.  Here was the wall after the hall bathroom was removed.

The bathroom wall down to the 2 x 4 's

Then the picture below was with the new plumbing and new electrical.  For two bathrooms instead of just the one original.   I do have a post on renovating my hall bathroom if you are interested in reading it.  If you like bathroom remodeling details, take a look at that post.

wiring roughed in for bathroom

I found the new style of pipes amusing.  You don't need to be a genius to figure out the red pipes are for hot water and the blue for cold.  And of course, all that new electrical wiring!

Back to the kitchen!  The electricians installed a ton of wiring.

electrical wiring roughed in and hanging from kitchen ceiling

And I was able to install beautiful fixtures like this!

metal and glass hanging light fixture

And this.

modern metal and bubble glass kitchen light fixture

With reproductive outlets like below.  Because people have been asking, here is a link to the vintage reproduction switch and for the vintage switch plate covers.

reproduction push button switch

Ooops, I just noticed when I took this picture that the bottom screw was missing.  It isn't anymore!

Thanks for stopping by to read about updating my home from knob and tube wiring.  If you enjoyed seeing these detailed images of my knob and tube electrical renovation, please take a look at a few of my other posts showing detailed images of the renovations/remodel.

***Please note that I am not an electrician and I used a licensed electrician to do all the electrical work in my home.   I'm just an interested homeowner, with a very detailed inspection report who likes to share information on my blog.***

My kitchen remodel.  I bought a house without a kitchen.

My 5 x 8 bathroom remodel - it was a total gut!

Vintage Picture Rails - How they are used.

How to Replace Knob and Tube Wiring With Romex

Source: https://momcrieff.com/my-house-had-knob-and-tube-wiring-here-is-how-i-updated-it/