I often see missing junction box covers on my home inspections, but why is it important to cover our junction boxes?
First of all, the cover is a safety item which keeps people from being able to accidentally touch electrical wire unions. But also, when you splice one or more wires together, it actually creates resistance to electrical flow - which in turn creates heat. When you have multiple wires in a junction box (like in the picture to the left) Not only does the junction box cover protect humans and the wiring from accidental contact, it also would help prevent the spread of a fire should the wires overheat and cause combustion.
How common is this occurrence? According to a relatively recent study by John R. Hall Jr. for the National Fire Protection Association: In 2007 alone, there were an estimated 51,800 home or structure fires reported in the US that involved some type of electrical failure as a contributing factor to the fire. These electrically related fires accounted for approximately 450 civilian deaths, 1,640 civilian injuries, and $1.2 billion in direct property damage.
So before you pass by that junction box with the missing cover, be sure to buy some proper covers from the hardware store and hire a qualified electrician.
Mike McFadden, Certified Master Home Inspector in Orlando, FL