# Cloth Wiring Replacement in Boston > Cloth wiring replacement for older Boston-area homes: rubber and cloth cable judged circuit by circuit, replaced with grounded cable, BX and splices sorted out. URL: https://deckerbostonknobandtube.com/cloth-wiring-replacement/ [Decker Boston Knob and Tube](https://deckerbostonknobandtube.com/) arranges cloth wiring replacement across Boston, Cambridge, Somerville and nearby cities, carried out by licensed and insured electricians. Cloth wiring here means cable whose conductors are insulated with rubber and wrapped in woven fabric, usually two wires bundled in a cloth jacket and stapled to the framing, from the decades after knob and tube. It is judged run by run on condition. Some of it needs replacing now, some can wait for a planned project, and in an older house it may sit alongside knob and tube and early armored cable. When most of the house is old wiring of one kind or another, a [whole house rewire](https://deckerbostonknobandtube.com/whole-house-rewiring/) replaces every type in one pass. ## What happens on the first visit The first visit finds out where the cloth cable is, what it connects to and what shape it is in. Those are three separate questions, and the answers differ from room to room. ### Where it is and what it joins The electrician traces each circuit from the panel and records what it is made of. Cloth-sheathed cable may be spliced onto knob and tube where a mid-century owner extended a circuit, or onto later cable where a remodel stopped. Each junction is a potential weak point and a scope boundary, and the [guide to knob and tube mixed with newer cable](https://deckerbostonknobandtube.com/guide/knob-and-tube-mixed-with-romex/) explains why they matter. ### What condition it’s in Then comes condition, read where the cable can be seen without disturbing it: in the basement and attic, at the panel and at a sample of boxes. Where condition is in doubt, a de-energized circuit can be tested with an insulation resistance tester. Closed walls hide the middle of each run, and the written findings say which runs were seen, which were tested and which could only be inferred. ### What you get back You get a priority list. Runs with brittle insulation, damage or risky splices go first; intact runs that feed rooms due for renovation can be folded into that work; the rest are recorded. The [knob and tube vs cloth wiring guide](https://deckerbostonknobandtube.com/guide/knob-and-tube-vs-cloth-wiring/) shows how the two types are told apart. ## How rubber and cloth insulation fails The conductor inside is usually fine. The insulation around it is what ages, and it ages fastest where it is hot, bent or disturbed. ### Heat hardens the rubber Rubber insulation stays flexible only as long as it isn’t cooked. Decades of heat from light fixtures, a hot attic in summer, or an overloaded circuit harden it, and hardened rubber cracks when it is moved. The cloth over it was there for abrasion, not insulation, and it frays and sheds once the rubber under it is gone. ### Bends and terminations take the stress The tightest bends are where the cable enters a box and where the conductors wrap around device screws. Every outlet swap or fixture change flexes those few inches again. Damage tends to show there first, and an exposed bare conductor inside a box is how a working circuit turns into an arcing one. ### Later work and insulation over it Cable stapled to framing was moved and nicked by every later trade that worked nearby. Where blown-in insulation was later packed around it, the cable has less ability to shed heat. The Massachusetts text of the code rates new cable run through thermal insulation at its 60°C value, a sign of how much insulation changes the heat picture even for modern wire. ## Early armored cable and the ground question Houses with cloth cable may also have early armored cable, often called BX, from the same period. Its conductors are the same rubber-and-cloth type, inside a spiral metal jacket. ### Why the jacket matters On circuits with no ground wire, that metal jacket was sometimes the only path for fault current back to the panel. The path depends on every joint and box connector staying tight, and old armor can be rusted, loose or broken along its length. Sharp jacket ends at boxes can also cut into the insulation they were supposed to protect. ### How it is handled The electrician tests whether the jacket carries fault current at each box before treating the circuit as grounded. Where it can’t be shown to, the circuit is treated as ungrounded, and the [ungrounded outlet upgrade](https://deckerbostonknobandtube.com/ungrounded-outlet-upgrade/) page covers the choices for it. Where cloth cable and old armored cable share a circuit, the scope normally replaces both, so the circuit ends up on one kind of wire. Cloth cable, BX and knob and tube in one house? Start with a circuit-by-circuit map. It shows what to replace first and what can wait. Get an Estimate (617) 405-3599 ## What replacement involves Cloth-sheathed cable was installed like modern cable, along the framing and into boxes, so its routes are often reusable. ### Following the old routes Where the old cable ran through bored joists and straight into boxes, new grounded cable can often take the same path, entering through the same box openings. That keeps the number of new openings down compared with knob and tube, which took separate routes for each wire. Where a run can’t be followed, the Massachusetts text allows new cable to be fished between access points in finished buildings, and the [plaster wall rewiring](https://deckerbostonknobandtube.com/plaster-wall-rewiring/) page covers how openings are cut and closed. ### Boxes, devices and protection Old boxes are often too shallow to hold a grounded device and its wires without crowding, so they are replaced where needed. Every new 120 volt branch circuit gets arc-fault protection, which Massachusetts requires throughout a dwelling, and receptacles near sinks get ground-fault protection. That can mean panel spaces the house doesn’t have, which the [fuse box and panel upgrade](https://deckerbostonknobandtube.com/electrical-panel-upgrade/) page covers. ### Old wire left in walls Cloth cable sealed inside finished plaster is usually disconnected at both ends, confirmed dead and left in place, while runs in the attic and basement are pulled out. In a house built before 1978, opening more than six square feet of painted surface in a room makes the job lead-safe renovation work under the state’s Department of Labor Standards rules. The [asbestos and lead paint guide](https://deckerbostonknobandtube.com/guide/asbestos-and-lead-paint-during-rewiring/) covers both materials. ## Insurance, Mass Save and price Cloth cable is not knob and tube, and the difference can matter for both programs and insurers. ### Mass Save and insurers Mass Save’s assessment standards name knob and tube as the barrier to insulation, so correctly identifying a run as cloth-sheathed cable can change what an energy assessment allows. Insurers use the terms loosely; ask for a request in writing that says which wiring types it covers, then check the scope against it. The [Massachusetts insurance guide](https://deckerbostonknobandtube.com/guide/knob-and-tube-insurance-massachusetts/) explains what to ask. ### Code and price Massachusetts doesn’t require old wiring to be replaced because new work is added. Rule 3 of 527 CMR 12.00 lets an installation be modified without bringing the rest of it up to code, as long as the work creates or worsens no violation. Replacement is a decision about condition and plans. The [signs guide](https://deckerbostonknobandtube.com/guide/signs-your-house-needs-rewiring/) covers which symptoms call for a prompt look, and the [cost estimator](https://deckerbostonknobandtube.com/tools/knob-and-tube-cost-estimator/) gives a starting range without a phone call. ## What's included - Tracing every circuit and recording which runs are cloth-sheathed cable, knob and tube, early armored cable or later cable - Checking the insulation at boxes, fixtures and accessible runs, and testing circuits where condition is in doubt - A written order of priority: runs to replace now, runs that can wait for a planned rewire, and why - New grounded cable along the old routes where they can be reused, with new routes where they can't - Deeper boxes where old ones are too small for grounded devices - Arc-fault protection on every new 120 volt branch circuit, and ground-fault protection where Massachusetts requires it - Old armored cable assessed as a ground path and replaced where it can't be shown to carry fault current - Old circuits disconnected and confirmed dead, with reachable runs removed - A labeled panel schedule and a written summary of every old wiring type left in service, if any ## Replace now, replace with the next project, or keep and watch | | Replace now | Replace with the next project | Keep and watch | | --- | --- | --- | --- | | Fits a run that | Has crumbling insulation, scorched boxes, splices into knob and tube or sits under insulation | Is intact but feeds rooms you plan to renovate or rewire soon | Is intact, unmodified, lightly loaded and away from heat | | What happens | The circuit is replaced with grounded cable | Recorded now and replaced while walls are open later | Recorded, protected at the right fuse or breaker size and checked again | | Openings | Fishing and access holes, often along the old route | Folded into the renovation's own openings | None | | Grounding | A real ground to every outlet on the circuit | Ungrounded until then | Stays ungrounded | | Main risk | Cost and access now | Plans slip and the run stays in service longer | Conditions change if the run is disturbed, extended or insulated over | ## Related resources Learn What is the difference between knob and tube and cloth wiring? Four generations of wiring can share one Boston-area house. Here is how each one is put together, what it lacks, and why an electrician treats them differently. Learn What happens when knob and tube is mixed with Romex? Decades of kitchen remodels and added outlets can leave an old house with new cable spliced onto its original circuits. The cable isn't the weak point. The places where it meets the old wiring are. Decision Guide What are the signs your house needs rewiring? Old houses rarely announce bad wiring with one clear symptom. Sorting what you notice into urgent, worth planning for and not a symptom at all tells you what to do next. Learn Does knob and tube wiring have asbestos? Three old-house materials can sit right where a rewire goes: the wire's own covering, the paint on the plaster, and the fill in the attic. Here is what is known, what has to be tested, and how each changes the job. Cost Guide How much does knob and tube replacement cost in Boston? The range Boston-area owners budget with, the handful of things that push a house toward either end, and the public figures sitting inside every price. ## How a knob and tube job runs from first call to sign-off 1. First call Tell us what prompted the call, the town and type of building, how many units it has, and any deadline from an insurer, a sale or an insulation contractor. Photos, an inspection report or a Mass Save assessment help route the job to the right licensed electrician. 2. Assessment The electrician reviews the panel and the accessible attic and basement wiring, traces circuits, and notes which knob and tube is active, abandoned or mixed. You receive written findings and a scope, with access, patching and permit items listed separately. 3. The work The licensed contractor files the permit, then works area by area so the rest of the house keeps power. New cable is fished or run through open framing, the rough-in is inspected before walls close, and old circuits are disconnected and removed where reachable. 4. Completion Circuits are tested and labeled at the panel, the final inspection closes the permit, and you get the records: what was replaced, what was abandoned in place, and any knob and tube that remains. Those papers answer insurers, buyers and Mass Save. ## What this work looks like Old cloth-jacketed cable entering an old outlet box beside a new outlet with a new cable on a basement wall Coil of removed cloth-jacketed cable beside a coil of new white cable on a basement bench Find out which cloth runs need to go first Not every old cable has to be replaced at once. Tracing and checking the circuits sorts them into now, later and fine for now. Get an Estimate (617) 405-3599 ## Cloth Wiring Replacement questions ### Does cloth wiring need to be replaced if it still works? Not automatically. Working is not the test, because insulation can be cracked at a box while the circuit still carries power perfectly well. The test is condition: whether the rubber is still flexible, whether the run has been disturbed, spliced or buried in insulation, and whether its fuse or breaker matches the wire. Intact, unmodified runs away from heat can often wait for a planned rewire. ### Is there a test that shows whether cloth wiring is still sound? Partly. An electrician can test a de-energized circuit's insulation with an insulation resistance tester, which applies a test voltage and measures leakage between conductors, and can look at the wire wherever it is exposed. Neither shows every inch inside a closed wall. Results are read together with what the boxes and accessible runs show, and the written findings should say which parts were tested and which could not be seen. ### Why does cloth wiring look worst at ceiling light boxes? Heat. For decades, incandescent bulbs heated the top of the fixture and the box above it, and rubber insulation hardens faster with heat. The wires in a ceiling box are also bent tightly and moved every time a fixture is changed. So the ceiling box is often where brittle, cracked insulation first shows, even when the same cable looks sound a few feet away inside the ceiling. ### Can a new LED fixture go on old cloth-insulated wiring? An LED fixture runs cooler, but installing one means handling the old wires in the box, which is exactly where they are most brittle. If the insulation cracks as the wires are moved, the problem is now in your ceiling. Have an electrician look at the box before a fixture swap, and treat what they find there as a sample of the circuit's condition. ### What does cloth wiring replacement cost in the Boston area? It depends on how much of the house it covers. A few runs replaced along existing routes cost far less than a whole house, and when every old circuit is replaced, a typical Boston-area budgeting range is $8,000 to $25,000 or more. Within that, the price follows the number of live circuits, attic and basement access, plaster, how many boxes need replacing, panel space for new breakers and the patching scope. ## Related services ### Whole-House Rewiring → Every branch circuit replaced with new grounded cable, for houses where knob and tube, cloth cable and old splices are mixed through the walls. ### Ungrounded Outlet Upgrades → Two-prong and false three-prong outlets tested at the box and the panel, then fixed with grounded circuits, ground-fault protection or a wider rewire. ### Partial Replacement → The circuits still on knob and tube replaced from the panel to the last device, with a written record of anything left for a later phase.