Knob-and-Tube Wiring: What It Is, Where You’ll Find It, and What to Do About It
A common surprise in older Colorado homes — and what it means for safety, insurance, and remodeling.
If your home was built before the 1950s — especially in neighborhoods like Old North End, Patty Jewett, Manitou Springs, or rural parts of El Paso County — there’s a chance knob-and-tube wiring (K&T) could still be hiding behind the walls.
You may have heard it’s outdated or unsafe, but what exactly is it? And does it need to be replaced?
Let’s break it down.
What Is Knob-and-Tube Wiring — and Why Was It Used?
Knob-and-tube wiring was the standard in American homes from the 1880s through the 1940s. It gets its name from the ceramic knobs that secured wires to wood framing and the ceramic tubes that protected wires as they passed through joists and studs. Unlike modern wiring, which bundles hot, neutral, and ground wires together, K&T runs the hot and neutral wires separately — and it includes no ground wire at all.
At the time, this system was considered safe and effective. Most homes didn’t use much electricity — just a few lights or small appliances. The installation method allowed wires to dissipate heat naturally in open air, and many electricians took pride in the craftsmanship involved.
But as homes became more power-hungry and better insulated, knob-and-tube’s limitations started to show. It wasn’t built to handle heavy appliance loads, it doesn’t support grounding (which protects people and electronics), and it can become dangerous when surrounded by modern insulation.
Where You Might Find It in Colorado Springs
Knob-and-tube wiring is most often found in homes built before 1950. In Colorado Springs, that includes historic neighborhoods like the Old North End and parts of Manitou, as well as older rural properties around El Paso County. You’re most likely to find it in attics, basements, or behind original plaster walls that haven’t been renovated.
In many homes, the system was only partially replaced over time — meaning the wiring could still be active in hidden areas, even if newer outlets or lights have been added elsewhere.
What Are the Real Concerns?
On its own, and in perfect condition, knob-and-tube isn’t necessarily dangerous. But after decades of use — plus DIY modifications, insulation changes, and general wear — most of it is no longer functioning the way it was intended.
The biggest safety issues come from the lack of grounding, the age of the insulation (which can crack or fall apart), and the risk of overheating if it’s surrounded by insulation. Over the years, it’s also common to find spliced connections, improper tie-ins to modern wiring, and overloaded circuits.
How This Affects Insurance and Real Estate
If your home still has active knob-and-tube wiring, your insurance options may be limited. Some carriers won’t offer coverage at all; others may require documentation from a licensed electrician or proof that the system has been fully replaced.
This can also come up during a real estate transaction. Buyers, lenders, and inspectors are often cautious about older wiring, and sellers may be asked to replace it or offer a credit for the work before closing.
Should You Replace It?
In most cases, yes. If your home still has active knob-and-tube, it’s a good idea to plan for an upgrade — especially if you’re remodeling, adding large appliances, or making other electrical changes. Even if it’s functioning, the lack of grounding and aging insulation make it a liability in modern homes.
The good news? Replacement doesn’t always mean tearing out walls. In many cases, new wiring can be installed through attics, basements, and crawlspaces — and upgrades can often be completed in phases if needed.
A Note from Gaddie Electric
We’ve inspected and upgraded knob-and-tube systems in homes all over Colorado Springs. Sometimes homeowners don’t even know it’s still active — until something trips, flickers, or fails inspection.
Our approach is simple: we help you figure out what’s in place, what condition it’s in, and what your options are. No pressure. Just straightforward guidance and honest pricing.
Call us or request a free quote if you’d like to schedule an inspection or talk about next steps.