# How Does Knob and Tube Replacement Work?

> How knob and tube replacement works in a Minneapolis house: tracing, the scope, the permit, new cable, inspections, switch-over and the record. See each step.

URL: https://northloomminneapolisknobandtube.com/guide/how-knob-and-tube-replacement-works/

You've decided the old wiring has to go, and you want to know what happens next. Here's each step, from the first circuit we trace to the final inspection, and what it means for you.

New cable travels through the spaces the house already has.

Key takeaways

- We start by tracing every circuit, then give you a written scope listing circuits, openings and patching.
- The permit request is filed at or before the start of work: with the state in Minneapolis, with the city in St. Paul.
- We fish new cable from the attic and basement through the cavities your house already has; walls open only where framing blocks it or a new box goes.
- The new wiring is inspected before anything covers it; we switch circuits over one at a time, then comes a final inspection and your written record.

You’ve decided the knob and tube has to go, and now you’re picturing torn-open walls and weeks without power. It’s rarely like that. In most houses the job follows the same order: we trace every circuit, write a scope, get the permit in place, run new grounded cable through the spaces your house already has, have it inspected before anything is covered, switch circuits over one at a time, and finish with a final inspection and a written record.

At [Northloom Minneapolis Knob and Tube](https://northloomminneapolisknobandtube.com/), we replace knob and tube across Minneapolis and St. Paul. The details change with each house, but the order doesn’t, and this guide walks you through each step so you know what’s coming.

## What are the steps, start to finish?

The sequence: map circuits, file the permit, route new cable, rough-in inspection, switch over and test the old circuits dead, final inspection.

| Step | What happens | What it means for you |
| --- | --- | --- |
| 1. Trace | Every circuit matched to its rooms and identified | Walls stay closed; a short visit |
| 2. Scope | Circuits to replace, openings, patching and panel work, in writing | You approve the plan and the price |
| 3. Permit | Request for inspection filed | Nothing for you to do |
| 4. Route and rough-in | New cable run, boxes set | The rooms you’re using shift day by day |
| 5. Rough-in inspection | Inspector sees the new wiring before it’s covered | Openings stay open until then |
| 6. Close up | Openings patched to the agreed finish | Dust contained, rooms handed back |
| 7. Switch-over | Devices installed, circuits brought live one at a time | Short, planned outages |
| 8. Final and record | Final inspection; written record and panel directory | You keep the record |

You’ll be living with steps 4 through 7. The rest happens mostly out of your way.

## How do you figure out what needs replacing?

We trace. We switch each fuse or breaker off in turn and write down everything that goes dark. We identify the wire on each circuit as original, cloth-covered or modern, follow the exposed runs in your attic and basement, note every splice, and test the original circuits. Nothing gets opened. The [guide to whether knob and tube is still active](https://northloomminneapolisknobandtube.com/guide/active-vs-abandoned-knob-and-tube/) explains this step in detail.

## What will the written scope tell me?

It turns your circuit list into a plan you can approve.

- **Circuits**: Which original circuits we replace, and the new circuits laid out for each room.
- **Openings**: Where walls will be opened, room by room, and why.
- **Patching**: The finish each opening is closed to.
- **Panel**: Whether your panel or service changes.
- **Schedule**: Working days, and when the inspections fall.

## Who handles the permit?

Getting the permit in place is part of the job, and there’s nothing for you to file. In Minneapolis, the Minnesota Department of Labor and Industry issues the permit and inspects; in St. Paul, the city’s Department of Safety and Inspections does. The request is filed at or before the start of work. A typical Minneapolis rewire of 15 to 30 circuits in a one-family home carries a $191 state fee. The [permit guide](https://northloomminneapolisknobandtube.com/guide/minneapolis-electrical-permits-for-rewiring/) has the details.

## How does new cable get into finished walls?

Through the hollow spaces your house already has.

- **From the attic**: We drill down through the top plate into each stud bay on the top floor.
- **From the basement**: We drill up through the bottom plate into the first-floor walls.
- **Between floors**: Through closets, chases and walls that stack one above the other.
- **Openings**: Where a fire block, brace or header stops the cable, and where a new box goes.

We set new boxes sized for the new cable and devices, since original boxes are often too shallow. [Plaster-wall rewiring](https://northloomminneapolisknobandtube.com/plaster-wall-rewiring/) shows how we cut and patch openings in plaster.

## Why do the holes stay open for a while?

Because the inspector has to see the new wiring first. Before any opening is closed or insulation added, the inspector looks at the new cable, boxes and connections. Minnesota’s rules require wiring that will be concealed to be inspected first. So the openings stay open until that visit, and we group the work to keep that window short.

## When do the walls get closed up?

Once the rough-in passes. We close openings to the finish you agreed: patched and ready for paint, or left clean for your plasterer. Floors stay covered throughout, and we close or protect openings at the end of each day.

## Will I lose power while you switch things over?

Only briefly, and you’ll know when. We install devices and fixtures, then bring new circuits live one at a time. Your house keeps running on its old wiring until each circuit is switched, so outages are short and planned, and your furnace or boiler stays on a working circuit. If the panel is being replaced, it’s usually changed at the end, with the new circuits landing on it directly.

## What happens to the old wiring?

We disconnect each original circuit we replace at its source, not just at a switch, and test it dead wire by wire, since hot and neutral often travel separately. We can pull exposed runs from the attic and basement; runs sealed in finished walls stay in place, dead.

## What do I get at the end?

The final inspection covers the devices, the panel and the finished work. Then you get your record: a circuit list, a typed panel directory, what was disconnected and how it was tested, and the permit and inspection dates. Your insurer, a future buyer and any insulation contractor will all ask for it.

## Does my kind of house change the process?

The order stays the same, but the details shift.

| Your house | What changes |
| --- | --- |
| Story-and-a-half with an open attic and basement | Most routing from above and below; few openings; a quick switch-over |
| Two or three stories with radiators | No duct chases; closets and stacked walls carry cable; more openings between floors |
| Duplex or triplex | Each unit traced and scheduled separately; per-unit permit fees; common areas on a house panel |
| Finished basement | Fewer basement routes; more openings in first-floor walls |
| Vermiculite in the attic | Attic work waits for testing; routes avoid disturbing it |

## What do I need to do?

Not much, but a few things help.

- **Before tracing**: Clear paths to the panel, the attic hatch and the basement ceiling; pull together any reports, letters and past records.
- **Before work**: Approve the scope; tell residents or household members the schedule.
- **During work**: Move small items off the walls being opened each day; keep pets away from work areas.
- **After**: Keep the record with your house papers and send copies to anyone who asked for it.

## Will my outlets and circuits be laid out differently?

Yes. A rewire replaces your circuits, and it also redraws them. Kitchens get at least two 20-amp small-appliance circuits for the counters, bathrooms a 20-amp circuit with ground-fault protection, laundry its own circuit, and bedrooms and living areas arc-fault protection. We add outlets where your furniture and appliances actually sit. The layout is part of the scope, so you see it before work starts.

## How long will all of this take?

The working days depend on your floors, access and circuit count, and the inspections add their own scheduling. The [guide to how long a rewire takes](https://northloomminneapolisknobandtube.com/guide/how-long-does-it-take-to-rewire-a-house/) explains each factor, and the [guide to living at home during a rewire](https://northloomminneapolisknobandtube.com/guide/living-at-home-during-rewiring/) describes what each stage feels like. Questions about your house: [(612) 509-6597](tel:+16125096597).

## Questions about this guide

### Does replacing knob and tube mean tearing out all the walls?

No. We fish new cable through the hollow spaces your house already has, from the attic above, the basement below, and through closets between floors. A wall opens where a fire block or brace stops the cable, or where a new box goes. Your scope lists the expected openings room by room.

### Is the old knob and tube pulled out of the walls?

Usually not from finished walls. We disconnect each original circuit at its source and test it dead; runs sealed inside plaster stay where they are, because pulling them out means opening every wall they pass through. We often pull exposed runs from the attic and basement, and your record says which is which.

### Who patches the openings after a rewire?

That's settled in the written scope before work starts. Openings can be closed and left ready for paint, or left clean and square for your own plasterer or painter. Painting and decorative plaster usually sit outside an electrical scope, and the scope should name them either way.

## The service behind this guide

- [**Whole-House Rewiring** Most rooms still on the original wiring? We replace every branch circuit with new grounded cable, the knob and tube and everything spliced into it since, under one permit and its inspections.](https://northloomminneapolisknobandtube.com/whole-house-rewiring/)

## More guides

- [**How Long Does It Take to Rewire a House?** You need to plan your life around a rewire, and you want a number. Your house decides it more than anything else. Here's what sets the schedule, and how to read the one in a quote.](https://northloomminneapolisknobandtube.com/guide/how-long-does-it-take-to-rewire-a-house/)
- [**Can You Live at Home During a Rewire in a Minnesota Winter?** Most people do. We move through your house room by room, outages are short and planned, and your heat stays on.](https://northloomminneapolisknobandtube.com/guide/living-at-home-during-rewiring/)
- [**Who Issues the Electrical Permit for a Minneapolis Rewire?** You call the city for most permits, but not this one. Here's who inspects your rewire in Minneapolis, St. Paul and the suburbs, what it costs you and when the inspector comes.](https://northloomminneapolisknobandtube.com/guide/minneapolis-electrical-permits-for-rewiring/)
- [**What Replaces Knob and Tube Wiring?** Grounded cable is the short answer. The longer one covers the boxes, the protection, the wire sizes and a circuit layout drawn for how you live in the house now.](https://northloomminneapolisknobandtube.com/guide/what-replaces-knob-and-tube-wiring/)
- [**How to Compare Knob and Tube Rewiring Quotes** You have two quotes for the same house, and they're thousands apart. Usually that's because they cover different work. Line them up on the same points before you compare totals.](https://northloomminneapolisknobandtube.com/guide/comparing-knob-and-tube-rewiring-quotes/)