The extension cord is a safety device people treat as stationery: the warm-cord law

The most overloaded circuit in the average Lagos compound is not behind the wall - it is the length of soft cable on the floor that everything gets added to, the cord that carries the freezer tonight and the iron next week because it was the one nearest the socket. A mains cord is a safety component with a rated capacity, and every habit this page questions is the household spending that rating like it was infinite. The rules below are one physics sentence - heat is the receipt of over-drawing - written out for the things the cord market never prints.

The warm-cord law

Current through a thin conductor makes heat; the cord's rating is how much it carries without cooking its own insulation, and the desk's field rule is the simplest one in the whole electrical shelf: a cord that gets genuinely warm in the hand under load is too thin, too long, too coiled, or too busy - and the answer is never the 'it's fine, it's just warm' that precedes every scorched socket the socket-burn page documents. The coil is the habit nobody names: a reeled cable feeding the compound's far end, its full length bundled on the reel, is a heater with a cord inside it - the same copper, the same amps, no air to shed the heat, and the trade's one-line law is to uncoil what is carrying real load.

The four failure modes, in the order of the household's habits

• The daisy-chain: the adapter block in the wall, its outlets full, one of its sockets carrying the socket strip with its own five plugs - every joint is resistance, every split is a bet that nobody upstream overheats, and the chain's arithmetic is the whole circuit's load through the wall's single point; the desk's line is the breaker's: one cord, one wall, one load family.
• The outdoor cord used indoors and the indoor cord used outdoors: the jackets are the rating the weather reads - the sun UV-kills an indoor sheath the year it lies by the gate, and the rain enters the seam that was never sealed for it, which is the gen-page's 'cable chosen, not inherited' sentence from the cord's side; the outdoor class exists, costs little more, and the label states its class plainly.
• Under the rug and through the doorway: the furniture leg and the heel crush the strands inside a cord that looks fine outside, and the broken strand is the joint that heats - the desk puts 'it works' here as the danger phrase it is, because a damaged conductor is intermittent until it is an arc; cords run along walls, in the open, where the eye can see them and no chair back bends them.
• The high-heat appliance on the general-purpose cord: the iron, the heater, the kettle, the freezer's compressor and the well pump are the load class that spends a thin cord's whole budget in one plug - the rating figure is on the cord's own moulding and the appliance's plate, and the appliance-cord's honest sizing is a question for the tradesman rather than the market-stall's 'strong cable'; the rule that needs no numbers: the heavy things plug into the wall, not into the extension.

The temporary in its name

The cord's purpose is the week, the party and the gen's hours - and the household whose layout needs six cords is telling the house a wiring truth: the answer is a real socket added to the room by the licensed hand, not a permanent cable's walk across the floor. The same paragraph buries the two plugs in a wire trick that the generator page has already prosecuted: the mains and the gen sharing a socket through a cord's ends is the backfeed that kills, and the changeover exists so the cord never becomes a wire of two meanings. Every temporary habit that outlives a season is the socket conversation.

The desk's standing rule

Uncoil the load, single-chain nothing, outdoor jackets outdoors, nothing heavy except from the wall, nothing pinched under the rug, and the warm cord retired rather than forgiven - the list is the whole discipline of the house's softest cable. The extension cord is the one wire in the compound a guest can hold in both hands while it carries the room's power; every rule above exists so the thing in their hands stays the temperature of the furniture it is.