Lighting fixture wiring connected with Copper wires and AL branch circuit wires. Notice the pitting in these wires (the grooves in the shiny metal part of the wire). This is a serious condition especially if the wire has become “brittle”. Call Cullen Electric today if you need this inspected in your home! We have been updating AL wiring systems for 30 years.
Notice the pitting on the shiny part of the white wire? The deep grooves in it? That’s what happens over time as Aluminum wire breaks down in a process known as “oxidation”. As the metal oxidizes it becomes “pitted” and gaps form, at the termination points, between the wire and the screw. This “gap” causes resistance as the electrons try to “jump” across those gaps. That resistance causes heat which in turn causes fires. This is a SERIOUS condition and should be looked at by a professional.
This condition occurs when untrained personnel work on AL wiring systems. They attach Copper wires with Aluminum wires without the proper connecting devices. The subsequent chemical reaction between the two leads to “pitting” between the metals. The electrons “jump” across the barrier, creating resistance. This resistance causes heat which will burn your home down. The wires under the black wire nut “melted” the wirenut. This homeowner was lucky the breaker opened before the had a full fledge fire.
If you have AL wiring and someone who does not have the expertise to work on it…has….call a Pro IMMEDIATELY.