When overloaded, power strips often become overly hot. Same situation occurs when the contacts become work or corroded, and their contact resistance increases substantially. Such effects accelerate the contact deterioration and the resistance (and therefore dissipated power) increases further, sometimes until the contacts heat so much they start a fire.
Such junction can be located in a junction box, or in a power strip. Wiring and power cords are also susceptible to overheating, but gross overload is usually required there.
Visual indication of heating, while it is still mild, could lower such risks significantly.
A thermochromic pigment was obtained from Middlesex University Teaching Resources webshop. It was mixed with an acrylic base, and used to coat a white plastic power strip.
The paint has color change threshold at about 30 °C, and changes color from orange to white.
The coating is not optimal, mainly due to the not-entirely-suitable acrylic base being used.
Acquire paint that goes from white to red. Apply over junction boxes in the walls, to provide visual indication of fixed installations deteriorating.
Use a microencapsulated smell agent in capsules that burst at set temperature, so an overheating contact causes a tracing smell way before a burning smell. (Especially important for junction boxes hidden behind furniture.)
New power strip
Disassembled power strip