# Apartment building rewiring in San Francisco

> Apartment building rewiring in San Francisco: a DBI permit for every unit, phasing around tenants, common-area wiring rules, meters and the PG&E service.

URL: https://fogcitysfknobandtube.com/apartment-building-rewiring/

**Service**

Knob and tube replaced unit by unit or building-wide, with a permit for each dwelling unit and power-off windows announced to residents.

Last Updated: October 30, 2026

**Where**

San Francisco and the East Bay: Berkeley, Oakland, Alameda and Piedmont.

**Local rules**

- An electrical permit from DBI before new wiring goes in, then a pre-cover and a final inspection.San Francisco Electrical Code 89.127
- A separate permit for each dwelling unit, except in single-family (R-3) buildings.DBI fee schedule
- Only owner-occupants of a single-family home may pull their own electrical permit.SF Department of Building Inspection
- No insulation around concealed knob and tube without a licensed electrical contractor's certification.California Electrical Code 394.12
- Up to $2,000 toward active knob and tube for income-qualified PG&E customers in an EASE Home project.BayREN

[Fog City SF Knob and Tube](https://fogcitysfknobandtube.com/) manages knob and tube replacement in apartment buildings and flats across San Francisco and the East Bay, from a two-flat Edwardian to a six-unit Romeo flat building. The electrical work is carried out by licensed and insured electrical contractors holding California C-10 licenses, under a separate DBI permit for every dwelling unit.

A building of flats is not a large house. Each unit is its own permit, its own set of inspections and, most of the time, its own household paying rent. Census figures show that 57.4% of San Francisco’s occupied homes built before 1940 are rented, against 49.3% statewide, and more than 52,000 of those rented pre-1940 homes sit in buildings of two to nineteen units. The permit record reflects it: of 2,023 DBI electrical permits filed since 2016 whose descriptions name knob and tube, 196 name a unit or apartment, with wording such as “rewire of apartment to remove knob and tube. subpanel in unit.”

## What happens on the first visit

The first visit tests every circuit in each unit in scope and records what it runs on: knob and tube, cloth-insulated cable, later cable, or a mix joined by splices. In a stacked building the test also follows circuits between floors, because the ceiling of a lower flat often carries wiring that serves the flat above, and a hall or stair light may be fed from one tenant’s fuse box. Those crossings decide how far a single unit’s rewire can go without entering a neighbor’s home.

The visit then looks at the building as a whole: the meter bank or house panel, the common-area lighting, the garage or basement ceiling that most risers pass through, the roof form over the top unit, and whether the address appears on DBI’s soft-story list. The owner gets a written scope and price for each unit, listing every opening and who closes it, and a permit and phasing plan for the building. Where no work is planned yet, a [knob and tube inspection](https://fogcitysfknobandtube.com/knob-and-tube-inspection/) covers the testing half alone.

## Why flats are wired as one building

San Francisco’s flat buildings were built quickly and to a few repeated forms. SF Planning’s Inner Mission North context statement describes two- and three-flat buildings and Romeo flats of usually four or six units, built after 1906 as high-density rental housing, many with flat tar-and-gravel roofs. The Eureka Valley context statement traces the two-flat form across nearly eighty years of construction, often on high basements into which later owners inserted garages.

Both details matter to the wiring. A flat roof can mean no walkable attic over the top unit, so its ceiling circuits are fished from walls and closets or reached another way, while the lower units are reached from the garage ceiling. Stacked closets, bathrooms and kitchens line up from floor to floor and give the cleanest vertical routes, which is why a rewire in one unit is easier when the units above and below are planned with it. A [whole-house rewire](https://fogcitysfknobandtube.com/whole-house-rewiring/) of a single-family home has none of these crossings; a flat building has them on every floor.

## Permits, inspections and what each unit costs

DBI’s fee schedule requires a separate electrical permit for each existing dwelling unit, except in R-3 occupancies such as a single-family house, and separate permits for common areas. Each permit carries its own pre-cover inspection before any wall closes, its own final inspection and its own Certificate to Connect Current, the Green Tag. The [permit guide](https://fogcitysfknobandtube.com/guide/san-francisco-electrical-permit/) covers DBI’s process in detail.

Current DBI fees for residential wiring run $305 for up to 10 outlets and devices, $450 for 11 to 20, $580 for up to 40 including a service upgrade of up to 200 A, and $740 for more than 40. A unit rewire with new kitchen and bath circuits usually exceeds 40, so the permit side of a building multiplies predictably:

| Building (illustrative) | Units over 40 outlets and devices | DBI permit fees at $740 per unit |
| --- | --- | --- |
| Two-flat | 2 | $1,480 |
| Three-flat | 3 | $2,220 |
| Four-unit Romeo flat | 4 | $2,960 |
| Six-unit Romeo flat | 6 | $4,440 |

Those figures are illustrative arithmetic on DBI’s published fees, before any wiring, common-area or service permit, or reinspection at $259 per half hour. There is no published San Francisco price band for rewiring a single apartment. The typical San Francisco range of $20,000 to $50,000 or more describes the electrical scope of a single-family house, and it does not divide neatly by units, because a building shares its service, risers and common areas. Each unit’s wiring is priced after its circuits are tested, and the [San Francisco cost guide](https://fogcitysfknobandtube.com/guide/knob-and-tube-replacement-cost-san-francisco/) explains what moves the number.

## Common areas, meters and the building service

San Francisco’s own amendments to the electrical code shape the wiring outside the units. Nonmetallic sheathed cable is permitted in wood-frame multifamily buildings of Types III, IV and V up to six stories, but not in the common areas of R-1 and R-2 buildings of Type IIIA construction, and not in nonresidential spaces. Premises wiring less than 8 feet above a walking surface is treated as subject to physical damage, which matters in the garages under so many flat buildings, and metal-clad cable is not permitted where it is subject to physical damage either. Hall, stair and garage runs are therefore planned as their own scope.

At the service end, a load calculation for each unit and for the building decides whether the existing meters and service can carry the new circuits. Permit text shows both outcomes: one Sunset filing called for “new overhead electrical service for both units (125 amps each) and replacement of knob and tube wiring in existing locations for both units,” while others add a subpanel inside each unit and leave the service alone. Of San Francisco’s knob and tube permits filed since 2016, 27.9% mention a subpanel. When the service does change, PG&E’s tariff gives a residential allowance of $3,255 per meter or dwelling unit toward service work and bills its estimated installed cost above that, with full payment before construction. The [electrical panel upgrade](https://fogcitysfknobandtube.com/electrical-panel-upgrade/) page covers the PG&E side.

## Phasing the work around residents

Most apartment rewires happen with people at home. Work is sequenced by unit, by stack or by floor, and each power-off window is set in the schedule and announced to residents in advance. Circuits are cut over in groups, so a unit loses power only while its own runs are being connected, and rooms being worked are covered and closed off. The [living at home during a rewire guide](https://fogcitysfknobandtube.com/guide/living-at-home-during-rewiring/) describes what a day of that looks like from inside the unit.

Two sets of rules sit alongside the schedule. DBI presumes buildings built before 1979 contain lead paint unless a certified inspector proves otherwise, and its safety guide calls for at least three business days’ notice to neighbors, a posted 32 by 24 inch sign and dust containment before openings are cut; the [lead and asbestos guide](https://fogcitysfknobandtube.com/guide/lead-and-asbestos-during-rewiring/) covers the details. And if any tenant has to leave a unit during the work, San Francisco’s Rent Board rules on temporary relocation and capital improvement petitions apply. Those filings, deadlines and passthrough limits are explained in the [rental property rewiring guide](https://fogcitysfknobandtube.com/guide/rewiring-a-rental-property-san-francisco/). Condominium and TIC buildings add co-owner consent to the same per-unit permits, which the [condo and TIC guide](https://fogcitysfknobandtube.com/guide/condo-and-tic-rewiring-san-francisco/) covers.

East Bay buildings follow their own city’s rules. Oakland, for one, issues commercial (E) electrical permits for residential buildings with three or more units rather than its residential permits for houses and duplexes.

## Insurance, soft-story work and rebates

Insurance often starts an apartment rewire. The San Francisco Chronicle reported on the owner of a three-unit Castro building who, after a non-renewal, concluded he had to replace the knob and tube fully to get new coverage, which meant opening plaster and offering tenants temporary relocation. A unit-by-unit circuit record gives an underwriter specific answers, though the carrier still decides; an [electrical inspection for insurance](https://fogcitysfknobandtube.com/electrical-inspection-for-insurance/) documents the building before or after the work.

Wood-frame buildings of five or more units with a soft ground story are covered by DBI’s Mandatory Soft Story Program, and retrofit work opens the same garage ceilings and walls that carry wiring up into the units. The [soft-story retrofit and rewiring post](https://fogcitysfknobandtube.com/blog/soft-story-retrofit-and-rewiring/) explains how the two are coordinated. Smaller buildings may reach BayREN’s EASE Home program, which reimburses up to $2,000 toward fixing active knob and tube for income-qualified PG&E customers in homes of four or fewer units, as part of a weatherization project; tenant income counts where the unit is rented. The [BayREN rebate guide](https://fogcitysfknobandtube.com/guide/knob-and-tube-rebate-bayren/) has the conditions, and BayREN decides eligibility.

## What a building quote should separate

An apartment quote is easier to compare when it is written per unit and splits the shared work out: each unit’s wiring, the common areas, the service and meters, the PG&E side, the permits by count, and plaster patching for each unit as its own line. Two quotes for the same building can differ simply because one includes the hall and stair circuits and the other leaves them for later. The [rewiring quote checklist](https://fogcitysfknobandtube.com/guide/rewiring-quote-checklist/) lists what to ask for, and a [partial replacement](https://fogcitysfknobandtube.com/partial-knob-and-tube-replacement/) can finish a unit that an earlier remodel half rewired.

**Scope**

## What's included

- A test of every circuit in every unit in scope, plus the common-area and house circuits, recording which run on knob and tube and which pass through another unit
- A written scope and price for each unit, listing every opening and who closes it, with plaster patching as its own line
- A permit plan: one DBI electrical permit per dwelling unit, plus common-area and service permits where they apply
- A phasing schedule with power-off windows set and announced to residents before work starts
- A load calculation for each unit and for the building service, so meters, panels and subpanels are sized once
- New grounded branch circuits routed through garage, basement, attic and stacked closet paths before any wall is opened
- Old runs disconnected at both ends, removed where reachable, otherwise identified and terminated
- A written circuit record and a labeled panel directory for each unit

**Choosing the scope**

## Three ways to schedule the rewire of a building of flats

| Compare | Unit by unit at turnover | Building-wide project | Phased by floor or stack |
| --- | --- | --- | --- |
| How it runs | Each unit is rewired while it is vacant | Every unit, the common areas and the service in one planned project | One floor or vertical stack at a time, with residents at home |
| Permits | One per unit, filed as each unit comes up | One per unit plus common-area and service permits, filed together | One per unit in each phase |
| Resident impact | None for the vacant unit; little for the rest | Every unit has scheduled power-off windows | Only the units in the current phase |
| Wiring shared between units | Runs through occupied units may have to wait | Risers and common-area runs replaced once | Runs in a stack replaced together |
| Service and meters | Often deferred, so a later unit can force a second change | Sized once for the whole building | Planned at the start, installed with the first phase |
| Knob and tube left live | In every unit not yet done | None in scope | In later phases until they are reached |
| DBI permit fees | The per-unit fee, each time a unit comes up | The per-unit fee times the number of units | The per-unit fee times the units in each phase |

**Read next**

## Related resources

- [Decision GuideWhat does rewiring a rental property in San Francisco involve?The landlord's side of a knob and tube job: permits unit by unit, working around tenants, the Rent Board's relocation rules and what a capital improvement petition can and cannot do.](https://fogcitysfknobandtube.com/guide/rewiring-a-rental-property-san-francisco/)
- [Decision GuideWhat does rewiring a condo or TIC unit in San Francisco involve?Why one unit's wiring is rarely only one unit's business, what DBI requires per unit, and what to settle with the other owners before work starts.](https://fogcitysfknobandtube.com/guide/condo-and-tic-rewiring-san-francisco/)
- [Decision GuideCan you live in a house while rewiring is under way?How an occupied rewire is sequenced, what a day without power in some rooms looks like, and when it is better to be somewhere else.](https://fogcitysfknobandtube.com/guide/living-at-home-during-rewiring/)
- [LearnDoes knob and tube wiring have asbestos?What the wiring itself is made of, which materials around it deserve a test before anyone cuts, and how lead-safe rules change the way openings are made and patched.](https://fogcitysfknobandtube.com/guide/lead-and-asbestos-during-rewiring/)
- [LearnHow does a San Francisco electrical permit work for rewiring?Who can file, what DBI charges, what each inspection checks, and why a Green Tag on its own does not prove the knob and tube is gone.](https://fogcitysfknobandtube.com/guide/san-francisco-electrical-permit/)

**How a job runs**

## From the first call to the Green Tag.

### First call

Tell us what started this: an insurer's letter, an inspection report, a remodel, an attic you want to insulate.

The age of the house, the number of units and any deadline shape the next step.

### Walk-through

Circuits are tested to separate live knob and tube from abandoned runs, and attic, basement and garage access is checked.

Plaster, trim and finishes are noted, and you get a written scope and price.

### The work

The permit is filed with DBI. New cable is fished along the planned routes and openings are kept small.

The pre-cover inspection happens before anything is closed.

### Patching, inspection and the Green Tag

Once the pre-cover inspection passes, the openings are patched. Plaster patching is included and shown as its own line in the quote.

After the final inspection and the Green Tag, old runs are removed or terminated and the panel directory is updated.

**On the job**

## What this work looks like

A bank of four round electric meters in a row on the garage wall of a San Francisco flat building

The common stair hall of a San Francisco flat building with a canvas runner on the treads during rewiring

Six new white cables stapled along a garage ceiling joist and turning up to the units above

Two new gray breaker panels side by side on a plywood garage wall of a two-unit building

**Questions**

## Apartment building rewiring: questions

### How much does it cost to rewire an apartment in San Francisco?

No published San Francisco price band exists per apartment, so each unit's wiring is priced after its circuits are tested. The permit side is public: DBI charges $305 to $740 per dwelling unit for residential wiring, so a six-unit building whose units each exceed 40 outlets and devices pays $4,440 in permit fees before any wiring.

### Who can pull the electrical permits for a rental building rewire?

A licensed contractor registered with DBI's Central Permit Bureau. San Francisco's homeowner electrical permit covers only a stand-alone single-family home that is the owner's primary residence, and the owner must do the work personally, so it does not apply to a two-flat or larger building, or to an LLC owner.

### Do common hallways and stairs need different wiring from the apartments?

Sometimes. San Francisco allows nonmetallic sheathed cable in most wood-frame multifamily buildings up to six stories, but not in the common areas of R-1 and R-2 buildings of Type IIIA construction, and not in nonresidential spaces. Common-area work also takes its own DBI permit, separate from the units.

### Does the building's meter bank have to change when the flats are rewired?

Only when the load calculation says the existing service and meters cannot carry the new circuits. Some rewires add a subpanel in each unit and keep the service; others replace the meter bank, especially when units gain electric ranges or heat. PG&E's residential allowance toward service work is $3,255 per dwelling unit, with the rest billed by PG&E.

### How do residents find out when their power will be off?

Power-off windows are set in the phasing schedule and announced to residents before work starts, unit by unit, so nobody learns about an outage at the panel. Each window covers the circuits being cut over that day, and power returns between windows. Where a tenant has to leave the unit, Rent Board rules apply as well.

**Related services**

## Other work on the same wiring

### Mixed-use buildings

Knob and tube replaced in buildings with a shop below and flats above, with the storefront wired to commercial rules and the work planned around both.

### Whole-house rewiring

Every old branch circuit replaced, new circuits added where the house needs them, and the panel sized for the load.

### Electrical panel upgrade

A fuse box or undersized panel replaced, the service resized when the load calculation calls for it, and PG&E's side coordinated.