Best outlet covers for plugs in use: the box that locks the plug in, for the outlets that are never empty

The gap every other cover leaves

A tamper-resistant outlet's shutters are open around a plug that is in. A sliding plate's shutter is held open by the plug. A plug insert has been removed to make room for the plug. So every outlet with something plugged in, which in a living room is most of them, is exactly as exposed as it was in 1990: a toddler pulls the plug halfway out, and the live blades are showing, at the height of a crawling hand. An in-use cover is a box or a shroud that screws to the outlet and encloses the plug behind a lid an adult can open and a child cannot. It is the one outlet product that a house full of TR receptacles still needs; the rest of that logic is in are outlet covers necessary.

Box or slim cover

A box (Wappa, Jool) stands off the wall an inch or two and has room inside for a phone charger's wall-wart or a game console's adapter; Wappa publishes its interior as 6.4 by 3.9 inches. The cords exit the bottom. Safety Innovations' Twin Door box goes further again, at 5.4 by 3.2 by 2.8 inches of usable interior, which is the one to buy when the thing in the outlet is a baby-monitor brick rather than a lamp plug; the trade is that it stands off the wall the most and is sold one to a box. Wappa's lid is a double lock; Jool's is press-to-open, which is faster for adults and easier for a two-year-old to work out; the Twin Door wants a button on each door at once. A power strip is its own problem, because the whole strip lies on the floor: Wappa's 13-inch box swallows a standard six-outlet strip with the cords out the sides, and it is covered with the cord question in how to babyproof cords.

How we ranked these

Bulk weighting. None of these states a UL listing on the pages we read, so standards is flat and the ranking turns on the lock (double beats single), the honesty of the install description (Wappa's three steps start with turning the power off), and room inside. Wappa's box gets an install bump on this page for shipping both plate styles and screws. Rubric on how we choose; the empty-outlet covers are in best outlet covers for babyproofing.

The install is electrical

An in-use box replaces the outlet's cover plate with the box's own plate: breaker off, old plate off, new plate and box on with the supplied screws, breaker on. The receptacle itself is not touched, but you are working at a live outlet with the plate off, so the breaker is not optional. If you cannot identify the breaker, use a plug-in tester before you unscrew anything. Ten minutes per outlet once you have done one.

Who should skip all of these