Shingles is the reactivation of a viral infection in the nerves to the skin that causes pain, burning, or a tingling sensation, along with an itch and blisters in the skin supplied by the affected nerve. It is caused by the varicella zoster virus[1] , or VZVâthe same virus that causes chickenpox.
Types of electrical circuits. There are three main types of circuits encountered in a domestic situation. They are ring circuits, radial circuits and lighting circuits.
Class 1, 2 and 3 circuits are defined primarily in terms of the power supply to which they are connected. Power supplies are generally batteries, transformers or electronic power supplies. When working on an existing installation, it is a simple matter of identifying the power source and checking its marking.