Is it safe to use an extension cord permanently in an older home with limited outlets?

Short answer

Why people ask this

Older homes often have too few outlets, two‑prong receptacles, or knob‑and‑tube wiring, so people look to extension cords to bridge the gaps. They may want to avoid opening plaster walls or can’t make permanent changes in a rental. Others are trying to power space heaters, window ACs, or home office gear from a single 15A circuit. Cost, convenience, and the difficulty of adding outlets in lath-and-plaster walls drive the question. They also worry about overloading fragile, ungrounded circuits and need a safer workaround.

When it might be safe

There are no commonly accepted situations where this is considered safe.

When it is not safe

• Extension cords aren’t designed for continuous, fixed wiring and violate electrical code when used as permanent wiring.
• Older homes may have ungrounded two‑prong outlets and brittle insulation, increasing heat and shock hazards when cords carry ongoing loads.
• Common high-draw items in older homes (space heaters, window ACs) can overheat cords and old receptacles on 15A circuits.
• Daisy‑chaining cords or running them under rugs to reach distant outlets traps heat and can damage lath‑and‑plaster surfaces.
• Loose, worn receptacles typical in vintage boxes don’t grip plugs well, leading to arcing at the cord connection.

Possible risks

• Fire from overheating or arc faults at old outlets, brittle wiring, or compressed cords behind furniture.
• Shock risk on ungrounded circuits and metal‑cased appliances when using two‑to‑three‑prong adapters.
• Frequent nuisance trips or overfusing in fuse panels, masking dangerous overloads on aging branch circuits.
• Damage to historic plaster, baseboards, or cords from repeated pinching or tacking along walls.
• Insurance claim disputes if a fire involves a cord used as permanent wiring against code.

Safer alternatives

• Have a licensed electrician add properly grounded outlets or a new circuit; surface‑mount raceway can avoid opening plaster walls.
• Install GFCI/AFCI protection and replace worn two‑prong receptacles with grounded outlets where a grounding path exists, or GFCI (labeled No Equipment Ground) if it doesn’t.
• Create dedicated circuits for high‑load devices (space heaters, window ACs, microwaves) instead of sharing a single 15A vintage branch.
• Use lower‑wattage options (LED lighting, oil‑filled radiators with thermostats, or ceiling fans) to reduce circuit load while you plan upgrades.
• If a temporary stopgap is unavoidable, use a single heavy‑duty, short, 12‑ or 14‑gauge cord to one low‑wattage device only, fully uncoiled, visible, and not under rugs—then schedule a permanent fix.

Bottom line

In older homes with limited outlets, an extension cord shouldn’t be a permanent solution. Aging wiring, ungrounded receptacles, and higher loads make overheating and shock more likely. Plan a permanent, code‑compliant upgrade and use only minimal, short‑term cord use while you get it done.

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