200-Amp Service Change? St. Louis Won't Let You Permit It
Revised October 21, 2026
Is knob and tube wiring still safe?
Original knob-and-tube can keep working, but it was built for a house with toasters and irons, not a modern load. According to home inspectors at InterNACHI, its dangers come from its age, improper modifications, and building insulation that envelops the wires, and it has no ground wire. Have a qualified electrician evaluate it, and replace any wire that is brittle or cracked.
Keep reading ↓The basement light is a bare bulb on a pull chain, and when you yank it the bulb hums before it settles. Over the washer, two separate wires run side by side through white porcelain knobs nailed to the joists, a few inches apart. Upstairs the window unit kicks on, and the bulb dips. The air smells like damp brick and old dust.
You follow the wires with a flashlight to a splice wrapped in masking tape gone brown and brittle. Your thumb is already on the hardware store app.
Stop there, and read the City of St. Louis permit page before you buy anything. What you can’t permit yourself: “You may not apply for permits for service changes, rehab, or new construction.” If the electrician’s quote says service change, that permit is not yours to pull, and the page says those jobs need to be performed by a licensed contractor. What you can: pass a short test from the Building Division’s Electrical Section, and you can get a permit for a room addition, repair or modification to an existing system on an owner-occupied single-family home. An extra outlet on the bedroom circuit? Possibly yours, after the test. A service change at the panel is a permit no homeowner may apply for. Read that twice before you text the brother-in-law with the voltage tester. The Electrical Section is at 1200 Market, Room 425, at 314-622-3313.
Upstairs, the warning signs are things your hand and nose catch first. Put the back of your hand on the outlet cover that feeds the power strip, the phone charger and the space heater. A plate that feels warm, a lamp that dips when something big kicks on, a whiff of hot plastic near a switch: those are the things to write down and show an electrician.
In this city, those signs live in very old houses. When University of Missouri-St. Louis researchers studied older homeowners in St. Louis, the average age of their homes was 97 years. Over 80% had an electrical outlet used for more than two devices, which the researchers flagged as a fire risk, and the most common needed repairs they found were installing electrical plugs and weatherization. Tell that to the neighbor with the extension cord snaking under the rug: one of the repairs these houses need most is simply more outlets.
The City’s side of the bill is small. Every electrical permit carries a $25 application fee; a residential repair or modification inspection is $60, and $100 when it comes with a new service. The real money is the electrician: HomeAdvisor’s national cost data puts a 200-amp panel upgrade at $1,300 to $2,000. The rest of this page is how to know what you are paying for.
Is knob and tube wiring still safe?
Original knob-and-tube can keep working, but it was built for a house with toasters and irons, not a modern load. According to home inspectors at InterNACHI, its dangers come from its age, improper modifications, and building insulation that envelops the wires, and it has no ground wire. Have a qualified electrician evaluate it, and replace any wire that is brittle or cracked.
Here is the surprise. The original work is often better than what came after it: inspectors write that the original installation of knob-and-tube is often superior to modern Romex, and the porcelain lasts almost forever. The trouble is everything people did to it later, in the damp basements of brick houses that have outlived three owners.
Knob-and-tube runs the hot and neutral wires separately, usually 4 to 6 inches apart, so the wires can shed heat into free air. Blow insulation into that attic and the heat has nowhere to go, which is why the 2008 National Electrical Code requires that this wiring not be covered by insulation. Then come the decades of handiwork. It is not uncommon to find connections wrapped with masking tape or Scotch tape instead of electrical tape, and that many homeowners installed fuses rated too high for the wiring so they would blow less often, which let the wire itself take the heat.
Think of beige masking tape gone brown and brittle on a splice above the basement stairs. That is the realistic hazard: not the old copper, but the tape, the oversized fuse and the insulation someone packed around it without knowing.
How to tell what is in your walls, without touching anything
Take a flashlight to the unfinished basement or attic and look up at the joists. Knob-and-tube is insulated copper wire passing through porcelain tubes where it crosses the framing, supported along its length by nailed-down porcelain knobs. You will see two separate wires running parallel, inches apart, instead of one flat modern cable. Where the wires enter a device, they are wrapped in a flexible cloth or rubber sleeve called “loom.” Two-prong outlets everywhere are the other giveaway, since the system has no ground wire to serve three-pronged appliances.
If your house is newer, look for a different metal. InterNACHI writes that between approximately 1965 and 1973, single-strand aluminum wiring was sometimes substituted for copper branch-circuit wiring because of the sudden escalating price of copper. It quotes the Consumer Product Safety Commission: homes wired with aluminum wire manufactured before 1972 are 55 times more likely to have one or more connections reach “Fire Hazard Conditions” than a home wired with copper.
Either way, read the label on the outside of the panel and leave the cover on. What is behind it is the electrician’s job.
People are asking
What does a 200-amp electrical panel upgrade cost in St. Louis?
HomeAdvisor’s national cost data puts a 200-amp panel upgrade at $1,300 to $2,000, with a new power supply and meter adding $100 to $650 and permits and drywall repair adding $150 to $300. In the City of St. Louis, every electrical permit carries a $25 application fee, and the inspection fee for a residential service-only job is $60. Homeowners may not apply for City permits for service changes, so a licensed contractor has to do the job. Replacing a fuse box with a breaker box costs $1,500 to $2,000 in the same national data, and up to $4,500 if the wiring needs a complete overhaul.
The sounds and smells that mean call today
Old wiring rarely fails silently, and the warnings are things you can hear and smell. HomeAdvisor’s list of signs that a panel needs an upgrade includes an age of over 25 years, persistent flickering lights, overheating appliances, electric shocks upon contact, unusual hissing or crackling sounds, burn marks around the panel, and frequent breaker trips with high-load devices. Add the warm face plate and the whiff of hot plastic from the top of this page, and you have a checklist you can run with a flashlight and your nose.
Stand in the basement and listen while someone upstairs runs the microwave and the hair dryer at once. A faint buzz from the panel, a click and a dark room, a brown scorch mark on the panel door: none of those are “just an old house.” Write down what you saw and heard, and when. An electrician can diagnose a pattern far faster than a vague “the lights act funny.”
And a word about the way these houses got this way. InterNACHI’s inspectors note that when knob-and-tube was first introduced, common household appliances were limited to little more than toasters, tea kettles, coffee percolators and clothes irons, and that existing systems are notorious for modifications made to keep up with televisions, refrigerators and everything after. Many of those changes were made by insufficiently trained handymen rather than experienced electricians. Every owner of a century-old St. Louis house inherits a few of them.
Do you actually need 200 amps?
Not always. HomeAdvisor notes that most homes have electrical service between 100 and 200 amps. Amperage is how much your whole house can draw at once, so the question is what you plan to run. An electric range and dryer, central air added to a crowded panel, a heat pump, a hot tub, an EV charger: each one is more for the panel to carry. A gas house with one air conditioner often does fine.
Ask the electrician for a load calculation before you sign anything. A contractor who skips that step and quotes a bigger service anyway is guessing with your money.
Buying a house that sat empty? Read this first
If the house you love sat dark for a while, the meter cold and the basement smelling of damp plaster, know this rule before you set a move-in date. The City charges a re-inspection fee for structures whose electrical service has not been in use for six months or more, and if the re-inspection isn’t applied for, the power company can be ordered to keep the service disconnected until the City says otherwise. Ask the seller how long the power has been off, and budget for an electrician’s walk-through before the inspector’s.
Power’s off for the panel swap and the stove is dead? Eat in Glendale, Missouri tonight.
Fixing aluminum wiring the right way
The danger with aluminum lives at the connections, where outlets and switches meet the wire. According to InterNACHI, the CPSC recommends two methods for correction: rewire the home with copper wire, or use COPALUM crimps. Pigtailing with an ordinary twist-on connector is not one of them, and InterNACHI says that method is only effective if the connections between the aluminum wires and the copper pigtails are extremely reliable. That is worth knowing when a quote looks suspiciously cheap.
COPALUM is not a weekend fix. InterNACHI describes a specially designed metal sleeve and powered crimping tool that can be properly installed only with the matching AMP tool, typically around $50 per outlet, switch or light fixture. It also warns that not all licensed electricians are properly trained to deal with defective aluminum wiring, so ask how many aluminum jobs a contractor has done.
Fuse boxes, Federal Pacific and Zinsco
A fuse box is not automatically dangerous. The hazard is the one InterNACHI describes: a fuse rated too high for the wire, screwed in so the nuisance stops. A fuse protects the wire, so the wrong one turns the wire inside your wall into the weakest link. If you are replacing the whole thing, HomeAdvisor puts replacing a fuse box with a breaker box at $1,500 to $2,000, up to $4,500 if the wiring needs a complete overhaul, and replacing a Federal Pacific or Zinsco panel at $1,500 to $4,000.
Checking that your electrician is real
Because homeowners can’t permit a City service change or rehab, the license on the truck matters. Before you hand over a deposit, read our guide on how to check whether a contractor is licensed in Missouri, then get itemized bids that separate the electrical work from the plaster patching.
Warm outlet cover, flickering lamp, two-prong plugs everywhere? Get it looked at this week. Start with our guide to choosing an electrician, compare electricians working across the St. Louis metro, or browse every local pro on St Louis Near Me Directory.
If you’re the electrician who knows knob-and-tube by the smell of the basement, the homeowner with the warm outlet is searching for you tonight, so list your shop on St Louis Near Me Directory and get more customers.
Frequently Asked Questions
Is knob and tube wiring still legal?
Owning a house with it is not against the law, but working on it is regulated. The City of St. Louis has adopted the 2017 National Electrical Code, and homeowners may not apply for City permits for rehab or service changes, so those jobs need a licensed contractor. InterNACHI also notes that the 2008 National Electrical Code requires that this wiring not be covered by insulation.
Is it okay to buy a house with knob and tube wiring?
It can be, if you price it in before closing. Have a qualified electrician evaluate how much original wiring is still in use, whether insulation covers it, and what the panel is. If the house sat empty, ask about the City’s re-inspection rule for service unused for six months or more.
Can you get home insurance on a house with knob and tube wiring?
Sometimes. InterNACHI says many insurance companies refuse to insure houses that have knob-and-tube wiring due to the risk of fire, with exceptions sometimes made where an electrical contractor has deemed the system safe. Ask your own agent before you commit, and get that electrician’s assessment in writing.
Is 100 amp electric good?
For many houses, yes. Most homes have service between 100 and 200 amps, and what decides it is your load: a gas house with one air conditioner is very different from one with an electric range, a heat pump and an EV charger. Ask an electrician for a load calculation.
How do I know if I have aluminum wiring?
Check when the house or its additions were wired. InterNACHI says single-strand aluminum was sometimes substituted for copper between approximately 1965 and 1973. Warm face plates, flickering lights and a hot-plastic smell at outlets are reasons to call an electrician.
Written by a dedicated team of St. Louis locals who live, work, and play right here in the St. Louis metro. Founder Lane Forman and team are committed to building the region’s most trusted directory by verifying listings and connecting local businesses with loyal customers across Missouri and Illinois.