Parallel circuit

A socket circuit wired as a loop, so load current shares two paths. The cable leaves the consumer unit, visits each socket in turn and returns to the same protective device. A UK signature design, it serves a large floor area from modest cable — and demands its own three-step continuity test, because a broken ring keeps working silently as two overloaded radials.

A series circuit has components along one current path, so the same current passes through each. Two resistors in series add to the total resistance, while the supply voltage is shared between them. An opening anywhere in that path interrupts current through both. Series describes the electrical connections, not whether the components look lined up on a drawing.

Voltage is the electrical potential difference between two points, measured in volts (V). It describes energy transferred per unit of charge, rather than how much charge is flowing. A battery can have voltage across its terminals even when no complete circuit exists and no current flows. Voltage and current are different quantities.

Current is the rate at which electric charge flows, measured in amperes (A), often called amps. In a simple closed circuit, the supply drives current through the load and back to the source. Current is not used up by a lamp: energy is transferred there. A cable current rating describes how much current it can carry in stated conditions, not how much it always carries.