EZSMART Corporation, ESA/ECRA #7012690 , North York , Ontario
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Daisy-chaining power strips — plugging one strip into another to extend the number of outlets available — is one of the most common electrical mistakes in Canadian homes and offices. It looks harmless because it works, at least initially. The failure is rarely immediate. It develops over weeks or months as the overloaded cord insulation degrades, until a failure occurs without warning. The Electrical Safety Authority (ESA) explicitly identifies daisy-chaining as a fire hazard and the Ontario Electrical Safety Code (OESC) prohibits it.
The core danger of daisy-chaining is current concentration: all the current drawn by every device connected to the second strip must pass through the first strip’s cord to reach the wall outlet. A cord rated for 15 amperes may be carrying 13 amperes of continuous load from a combination of devices — and when the first strip’s internal wiring is at or near its thermal limit, adding a second strip to the chain compounds the problem without triggering the wall circuit breaker. The fire starts in the cord or the first strip’s housing, not in the panel.
This is the most important thing to understand about daisy-chaining. The circuit breaker in your electrical panel is designed to protect the branch circuit wiring inside the walls — the 14 AWG or 12 AWG wire running from the panel to the outlet in the wall. It trips when the total load on the entire circuit exceeds its rating (typically 15A or 20A).
A power strip’s cord, however, is thinner than the wall wiring — typically 16 AWG or 14 AWG. A 16 AWG cord rated at 13 amperes in open air can carry that load without exceeding its rated temperature. But if the cord is pressed against a baseboard, coiled, run under furniture, or enclosed (as happens when a first strip is hidden behind a media cabinet), its ability to dissipate heat is reduced. The cord can reach dangerous temperatures while the wall circuit is drawing well under the 15A breaker threshold. The breaker trips when the circuit is overloaded — not when the cord is overheating. These are two different conditions, and only one of them triggers the protection you are relying on.
The Ontario Electrical Safety Code (OESC) prohibits daisy-chaining of flexible cords and extension devices. A power strip is a multi-outlet extension device, and plugging one into another creates a series of flexible cord runs carrying combined load — a configuration that does not meet the code’s requirements for installation and current capacity. The Electrical Safety Authority (ESA) reinforces this prohibition in its residential safety guidance, specifically naming daisy-chained power bars as one of the most common sources of preventable electrical fires.
This is not a technicality that affects only unusual setups. Home offices with multiple monitors, gaming setups with multiple consoles, and home entertainment systems with receivers, disc players, and streaming devices regularly use more outlets than a single power strip can provide — and the instinctive solution is to add a second strip. The instinctive solution is the prohibited one. See our guide on why power strips catch on fire for the detailed failure mechanisms that apply to both single strips and daisy-chained configurations.
The failure sequence in a daisy-chained strip configuration typically follows this pattern:
The result is a fire that starts behind furniture, inside a cable management box, or against a baseboard — locations where it burns undetected before anyone notices smoke. This is why investigations of electrical fires often find charred cord remnants in locations the homeowner assumed were low-risk.
Yes, and it may be higher. An extension cord used as a permanent connection from a wall outlet to a power strip is functionally identical to daisy-chaining in terms of current concentration — all devices draw through the extension cord’s wire gauge. Extension cord gauges are often lighter than power strip cords, and many extension cords sold at retail are rated for lower current than the power bar connected to them. The combination of a light-gauge extension cord and a fully-loaded power strip is a known fire scenario. Extension cords are intended for temporary use; they should not serve as permanent wiring for a media setup or home office.
The correct solution to a shortage of outlets is to add outlets — not to extend from existing outlets with strips and cords. An ESA-licensed electrician can add dedicated outlets in any location in the home that requires them. In a home office, this typically means two or three additional duplex receptacles on a dedicated circuit — a one-time cost that eliminates the need for power strips entirely and protects all connected devices from the overloading and arcing risks of chain configurations.
If a power strip is used, it should be a single strip — not chained — connected directly to a wall outlet, loaded to no more than 80% of its rated capacity, and used only for low-draw devices such as phone chargers, lamps, and computers. High-draw devices (space heaters, air conditioners, microwave ovens, coffee makers) should always be plugged directly into wall outlets on dedicated circuits. The surge protection provided by a surge-protected power strip is only as effective as the strip’s MOV components — a strip that has absorbed several large surges may no longer provide protection while still functioning as a power distribution point.
Homes with children face a compounded risk from daisy-chained strips. A setup with two or three strips chained together, with multiple cords running across a floor, creates both a cord accessibility hazard and a fire hazard from overloading. Children can pull on accessible cords, with multiple cords running across a floor, creates both a cord accessibility hazard and a fire hazard from overloading. Children can pull on accessible cords, dislodging the connection between strips and creating an arcing event at the disconnection point. See our guide on how to childproof electrical cords — the recommendation is the same: eliminate extension cords and power strips in high-traffic areas by installing outlets where they are needed.
The home office is the most common location we find daisy-chained strips — a monitor, desktop, docking station, printer, speakers, external drives, and a standing desk motor are all competing for outlets, and the instinctive solution is to add more strips. We typically find two strips chained together, often with the first strip pushed behind the desk where the cord is pinched against the wall and partially restricted. The cord of that first strip is carrying the full combined load of everything on both strips. In every case, the correct fix is to add a dedicated 20A circuit to the home office with four to six duplex receptacles placed at desk and floor level — removing every extension cord and strip from the room entirely. The cost of that installation is almost always less than the replacement cost of the equipment at risk from the fire or surge that would eventually result from the chained configuration. If you are running two or more power strips in any room, have an electrician assess your outlet layout before the strips do what overloaded strips do.
Need additional outlets to replace power strips and extension cords in your home or office? Our ESA-certified electricians serve the GTA. Call us at 416-838-9006 or visit our contact page — we will get back to you the same day.
Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp
