Electrical Installations and Equipment
Core concepts
Understand selection and erection principles: equipment must be suitable for the environment, voltage, current and duty. Know the importance of IP ratings, enclosure selection, ventilation, and segregation of Band I and Band II circuits. Be familiar with isolation and switching requirements, emergency switching, and the need for clear labelling and identification. Recognise that equipment must be installed per manufacturer instructions and that accessibility for maintenance is a design requirement.
Traps in questions
Questions often test whether equipment is suitable for the location (e.g. a standard socket in a wet area). Another trap is confusing functional switching with isolation, or omitting emergency switching where required. Watch for scenarios where Band I and Band II circuits share an enclosure without adequate segregation, and for equipment installed where it cannot be maintained.
Worked example / rule of thumb
When selecting an outdoor enclosure, match the IP rating to the exposure: IP44 for splashing, higher for jets or dust. Rule of thumb: if water or dust is present, never assume a basic IP20 accessory is acceptable; check the first digit (solids) and second digit (liquids) separately against the environment.