CDCS Exam Dumps : EXIN EPI Certified Data Centre Specialist

Electromagnetic field (EMF) strength around cables is primarily influenced by current, not voltage. In a single-phase system, the live and neutral conductors are separated, creating a larger magnetic loop area. This produces stronger stray EMF when current increases.

In a balanced three-phase system, the magnetic fields from the three conductors largely cancel each other out, resulting in much lower net EMF, even at higher currents.

Therefore, the correct statement is that increasing current in single-phase cables produces higher EMF compared to three-phase cables. Options B, C, and D incorrectly link EMF to voltage or incorrect current behavior.

Aerosol sprays release particulates and residues into the environment, which can contaminate sensitive ICT equipment. Such contamination accelerates corrosion, interferes with airflow, and increases particulate levels beyond ASHRAE recommended limits.

Proper cleaning should use HEPA-filtered vacuum systems or dry wipes, not aerosols. Even odor control aerosols are disallowed in critical rooms.

Therefore, aerosol cleaning solutions must never be used.

Residual current protection has evolved:

ELCB (Earth Leakage Circuit Breaker): Older type; voltage-operated. It trips when voltage develops between earth and exposed metal.

RCD/RCCB (Residual Current Device/Circuit Breaker): Current-operated. It detects imbalance between live and neutral conductors (indicating leakage current to earth).

Modern data centers use RCDs/RCCBs exclusively, since ELCBs are obsolete and unreliable if multiple earth connections exist. Thermal-magnetic breakers (D) provide overcurrent protection, not earth leakage.

Thus, not all residual current devices are based on the same principle.