Israel Electrician Licensing Exam key terms

The relationship stating that current through a conductor equals the voltage across it divided by its resistance (I = U/R). It underpins nearly every load, voltage-drop, and fault-current calculation.

The total opposition to alternating current from resistance plus inductive and capacitive reactance, expressed in ohms. It determines actual current flow in AC circuits and is used in fault-loop and short-circuit calculations.

The ratio of real power in watts to apparent power in volt-amperes in an AC circuit, equal to the cosine of the phase angle. Low values increase current for the same useful power and raise losses.

The product of RMS voltage and RMS current in an AC circuit, measured in volt-amperes (VA). It sets the current-carrying and transformer-sizing requirement regardless of phase shift between voltage and current.

Power delivered by three phase conductors displaced 120 electrical degrees apart. Total power equals √3 × line voltage × line current × power factor for a balanced load.

The reduction in voltage along a conductor caused by current flowing through its resistance and reactance. Excessive drop causes dimming, overheating, and unreliable operation of equipment at the far end.

A multiplier applied when summing individual loads to reflect that not all loads operate at full demand simultaneously. It allows smaller, economical supply and protective device ratings while remaining safe.

The greatest load, averaged over a defined interval, that an installation or circuit is expected to draw. It is the basis for sizing the supply, main protective device, and distribution board.

A tabulated list of every circuit in an installation with its load, protective device rating, cable size, and length. It documents design decisions and supports later inspection and modification.

The nominal area of a conductor in square millimetres, chosen so it carries design current without exceeding its temperature limit and meets voltage-drop and fault-current requirements.

The maximum current a cable can carry continuously under stated installation conditions without exceeding its rated conductor temperature. It is adjusted by correction factors for ambient temperature and grouping.

A multiplier below 1 applied to a cable's tabulated current rating to account for adverse conditions such as high ambient temperature, grouped cables, or thermal insulation. It prevents conductor overheating.

A correction factor reducing a cable's current rating when several loaded cables are installed close together, because mutual heating restricts heat dissipation. Its value depends on the number and arrangement of cables.

A resettable automatic device that opens a circuit on overload using a thermal element and on short circuit using a magnetic element. Its rating must coordinate with the cable it protects.

A protective device that trips when the vector sum of currents in the monitored conductors exceeds a set residual threshold, detecting earth leakage. It protects people against electric shock and limits fire risk.

The maximum prospective short-circuit current a protective device can safely interrupt without damage or dangerous arcing. It must equal or exceed the fault current at its point of installation.

Connecting exposed conductive parts of equipment to earth through a protective conductor so that a fault creates a low-impedance path that causes rapid disconnection of the supply.

Deliberate electrical connection of conductive parts, such as pipes, structural metal, and earthing terminals, so they sit at substantially the same potential. It removes dangerous touch voltages during faults.

A conductive element buried in contact with the ground that provides an electrical connection to earth. Its resistance must be low enough to ensure protective devices operate within the required disconnection time.

The complete path taken by fault current from the source, through the fault to the protective conductor and back to the transformer neutral. Its impedance determines whether disconnection occurs fast enough.

The measured total impedance of the earth fault loop, used to verify that the protective device will trip within the permitted disconnection time. It is a key value recorded during periodic inspection.

The potential difference a person could bridge between simultaneously accessible conductive parts, for example a faulty appliance casing and a nearby pipe. Keeping it low is the aim of earthing and bonding.

The current that would flow if a short circuit occurred at a given point in an installation, calculated from source voltage and loop impedance. It is compared with device breaking capacity and trip settings.

A safety procedure in which the supply is isolated, locked, and tagged so it cannot be re-energized while work proceeds. Only the person who applied the lock removes it.

The verified process of disconnecting, locking off, and proving dead an electrical supply before work begins. Proving dead with a tested voltage indicator is the step that prevents electrocution.

Confirming that a circuit is de-energized by testing between all conductors and earth with a voltage indicator that was proven functional before and after the test.

A two-pole instrument used to verify the presence or absence of voltage on a conductor. It must be proven on a known live source before and after each use to confirm it works.

A formal written authorization specifying the work, its hazards, isolation points, and precautions, signed before work starts and closed out afterwards. It controls high-risk tasks on or near energised equipment.

Immediate response to a casualty of electric current: isolate the supply, call emergency services, check breathing and pulse, and start CPR or place in the recovery position as indicated.

A rapid release of energy caused by an arcing fault between conductors, producing intense heat, light, pressure, and molten metal. It can occur without direct contact and demands arc-rated clothing.

The Israeli standard for electrical installations of buildings, the national counterpart to international wiring rules. It sets requirements for design, conductors, protection, earthing, and inspection in Israel.

The Israeli standard for household and similar electrical appliances, covering safety requirements for domestic equipment. Electricians use it when assessing appliance safety and suitability for installation.

The credential issued under Israeli law authorizing a person to carry out electrical installation work. It is granted after qualifying experience and passing the licensing examination, and it is graded by scope.

A low-resistance measurement confirming that a conductor or protective bonding path is unbroken and has acceptably low resistance. It is performed with the supply isolated using a calibrated ohmmeter.

A measurement applying a DC test voltage between conductors and earth to verify insulation is sound and free of moisture or damage. Results are compared with the minimum values required by the standard.

A test confirming that a residual current device operates within its specified time at its rated residual current and at half that current. It verifies the device will protect people as intended.

A method of connecting a three-phase motor or transformer winding in star for starting and delta for running, reducing starting current. Changeover must occur only after the motor has accelerated.

Devices and settings that disconnect a motor on overload, phase loss, or excessive temperature to prevent winding damage. Correct selection matches the motor's service factor and duty cycle.

The ratio of primary to secondary turns, which determines the ratio of voltages and the inverse ratio of currents in an ideal transformer. It is fundamental to selecting and testing distribution transformers.