Supply characteristics confirmed with the DNO or site records: voltage, frequency, phases, prospective fault current and external earth-loop impedance (Ze).

Earthing system identified (TN-S / TN-C-S / TT) and reflected consistently on drawings, schedules and labels.

Main earthing terminal, earthing conductor and main protective bonding sized and documented with the calculation or selection basis recorded.

Maximum demand assessed with a stated diversity basis; supply capacity and metering arrangements adequate.

Surge protection need assessed and the decision (fit / omit with justification) recorded.

Every circuit has overload and fault protection selected against its design current and the cable's characteristics, with device ratings recorded on the schedule.

Breaking capacity of every protective device meets or exceeds the prospective fault current at its point of installation.

Disconnection times verified for each final and distribution circuit (calculated Zs vs the device's requirement, from your licensed copy of the standard).

Additional protection by 30 mA RCD reviewed for socket-outlets, mobile equipment and locations requiring it; RCD types (AC/A/B) suit the connected loads.

Discrimination / selectivity between upstream and downstream devices considered and any non-selective pairs accepted knowingly.

Means of isolation and switching-off for mechanical maintenance provided, lockable where required, and labelled.

Cable sizes verified against installation method, grouping, ambient temperature and thermal insulation factors — the selection basis is recorded, not assumed.

Voltage drop within the agreed design limits for lighting and other circuits, calculated at design current.

Protective conductor / CPC sizes verified (adiabatic check or selection method recorded).

Cables selected for the environment: mechanical protection, UV, temperature, and fire performance where escape routes are affected.

Containment supports are non-combustible where required (no reliance on plastic-only supports on escape routes); segregation from data/other services maintained.

Identification: conductor colours, circuit references and warning labels consistent between drawings and installation.

Initial verification planned: schedule of inspections and schedule of test results prepared for the installation as designed.

Design information pack complete: schedules, calculations, assumptions register, drawings at the issue revision.

Electrical Installation Certificate (or minor works) signatories identified for design, construction and inspection & testing.

Departures or special measures (if any) documented and agreed with the client, with the engineering justification recorded.

Operation & maintenance information prepared: as-built drawings, device settings, RCD test intervals, recommended periodic inspection interval.

Supply disconnecting device provided, lockable in the OFF position, interlocked or shielded so live parts are protected when the door is open.

Emergency stop function reviewed: category (0/1), coverage, reset behaviour and device placement agreed and documented.

Control circuit supplies, protective bonding of the machine and door-mounted equipment checked; control transformer/PSU protection recorded.

Protection against automatic restart after power interruption where a restart could create a hazard.

Conductor identification, wire numbering and documentation match the schematic; technical file includes the electrical drawings.

Verification tests planned (continuity of the protective bonding circuit, insulation resistance, functional tests) with acceptance criteria from your licensed copy of the standard.

Assembly design verification route identified (testing, comparison or assessment) and the original manufacturer's verified design not exceeded.

Rated current, rated diversity factor, Icw / conditional short-circuit rating and IP rating stated and consistent with the application.

Temperature rise considered: enclosure size, ventilation or cooling matched to the installed heat dissipation.

Internal separation (form of separation) agreed with the client and reflected in the layout.

Creepage/clearance maintained around field-wiring terminals; incoming cable terminations sized with gland plate and bending space checked.

Rating plate / markings and routine verification records planned for the completed assembly.

Safety functions identified from the risk assessment (e-stop, guard interlocks, safe speed…) with a required performance level or SIL stated for each.

Safety-related parts of the control system separated from standard control; achieved PL/SIL evidenced (manufacturer data, architecture, diagnostics).

Validation of safety functions planned as distinct from general commissioning, with results to be recorded.

If the installation is a process-industry safety instrumented system, an IEC 61511 competent lead is engaged — outside the scope of this checklist.