Thousands of fires have been started due to “Crimp barrel” splicing over the last 50 years. Crimp splicing is an old, out-dated method of splicing wires together that for a long period of time replaced the traditional “Wire-nut”. This method of splicing was used all over the nation in millions of homes and businesses from the 1960’s through the early 1990’s.
The reason this method of splicing caught on in such a wide spread manner was simply because of the ease in installation. Rather than having to twist on wire-nuts with your fingers, electricians were now able to just slide a crimp barrel over the ends of the wires, crimp it with a crimping tool and wrap it up with electrical tape.
The reason these splices cause fires is because when the barrel is crimped, it doesn’t always make good contact with all the wires in the splice. When one of the wires in the crimp splice isn’t making a good connection and current (Wattage) is running through the splice, it begins arcing which creates heat. Once arcing starts, that’s when the fire hazard begins. Just like with rust, once the process begins it continues to get worse at an accelerated rate. Black carbon begins to form on all the copper or aluminum surfaces in the splice and as the current travels through the splice it now takes a bigger and hotter arc for the electricity to get through the splice.
Finally, the black electrical tape that was wrapped around the splice melts off and these carbon coated arcing connections are exposed becoming a fire hazard. Just like striking a piece of flint on a stone, if anything present is combustible, it could ignite. Fortunately, these splices are or should be in junction boxes and often do not ignite. It just breaks the circuit at that splice point and power is lost down stream of this point in your circuit. However, every so often the unfortunate occurs, something does ignite, either from a plastic junction box melting or something in the junction box com-busting and another electrical crimp splice fire goes down in the books.