EXIN CDCS Dumps Questions [2025] Pass for CDCS Exam
Updated EXIN Study Guide CDCS Dumps Questions
EXIN CDCS Exam Syllabus Topics:
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NEW QUESTION # 72
A data center requires an audit to find out whether it conforms with ANSI/TIA-942 Rated-3 (concurrently maintainable).
Will the network architecture be part of this audit?
- A. Yes, amongst other aspects, the network architecture should be Rated-3 compliant with the requirements of ANSI/TIA-942.
- B. No, only the type of cabling used will be audited.
- C. No, as concurrently maintainable only applies to electrical and mechanical (power and cooling).
- D. Yes, but only if the network administration does not comply with ANSI/TIA-606.
Answer: A
Explanation:
For a Rated-3 data center, network architecture is indeed a key component of the audit under ANSI/TIA-942. This rating requires concurrent maintainability across all systems, including telecommunications infrastructure. The network architecture must therefore meet specific redundancy and reliability standards to ensure uninterrupted operations during maintenance or failure of any single component.
Detailed Explanation:
Rated-3 requirements extend beyond electrical and mechanical systems to include network architecture. This ensures that telecommunications systems are also designed for concurrent maintainability, thus contributing to overall uptime and resilience.
EPI Data Center Specialist References:
EPI endorses comprehensive assessments for Rated-3 facilities, emphasizing that network systems must meet standards for redundancy and concurrent maintainability, which align with ANSI/TIA-942's holistic approach to data center reliability.
NEW QUESTION # 73
A new network storage device in a non-standard size rack of approximately 600 kg/1,300 lbs is going to be installed in the data center.
Are new floor loading calculations required?
- A. Yes, a structural engineer, approved/endorsed by the building owner, should carry out new floor loading calculations.
- B. No, as long as the equipment is less than 700 kg/1,500 lbs it will be within the limits.
- C. No, specifications of equipment brought into the data center will already be known during the design of the data center, and therefore the floor will be able to handle it.
- D. Yes, additional floor loading calculations need to be done by the floor manager, which should be verified by the safety engineer.
Answer: A
Explanation:
For heavy equipment, such as a network storage device weighing approximately 600 kg/1,300 lbs, new floor loading calculations are indeed required, particularly since the rack is non-standard. A structural engineer, approved by the building owner, should conduct these calculations to ensure the floor can safely support the new load without risking structural integrity.
Detailed Explanation:
Data centers are designed with specific floor load ratings, which are determined during the design phase based on anticipated equipment. When adding or replacing equipment that is significantly heavy or non-standard, reassessing the floor's capacity is essential to avoid overloading. A structural engineer has the expertise to verify if the existing floor can accommodate the weight and, if not, can recommend reinforcement measures.
This step ensures compliance with safety standards and helps prevent damage to the infrastructure, which could lead to costly repairs or even catastrophic failure in extreme cases.
EPI Data Center Specialist References:
EPI Data Center Specialist training advises that any changes in the data center load, particularly involving non-standard and heavy equipment, warrant a structural assessment. Ensuring compliance with floor load capacity is a critical safety and operational concern, as underscoring data center infrastructure reliability and safety is a priority in EPI's best practices.
NEW QUESTION # 74
You are working on the design of a new facility. The electrical riser of the building with high current power is located close to the area where sensitive IT equipment in the computer room will be located.
What should you recommend to reduce the amount of EMF coming from the electrical riser?
- A. Install three-phase power cabling based on three individual core wires
- B. Install three-phase power cabling based on a combined cable (e.g. XLPE etc.)
- C. Install bus bar trunking
- D. Install single-phase power cabling
Answer: B
Explanation:
To reduce Electromagnetic Fields (EMF) emanating from the electrical riser near sensitive IT equipment, three-phase power cabling in a combined cable (such as XLPE) is effective. Combined cabling helps reduce EMF by keeping the conductors tightly packed, which minimizes magnetic fields generated by current flow.
Cables like XLPE (cross-linked polyethylene) also offer better insulation, which helps mitigate EMF interference with nearby IT equipment.
Detailed Explanation:
Using a combined three-phase cable reduces EMF because the magnetic fields generated by each phase tend to cancel each other out when in close proximity. This arrangement helps reduce the overall magnetic field strength. In addition, XLPE and similar materials provide good insulation, making them a preferred choice for reducing EMF emissions around sensitive equipment.
EPI Data Center Specialist References:
EPI data center best practices recommend mitigating EMF interference through combined cabling arrangements, especially near areas where sensitive IT equipment is located. Reducing EMF is crucial to maintaining equipment reliability and ensuring compliance with safety standards.
NEW QUESTION # 75
What is the risk of high levels of hydrogen sulfide (H#S) in the computer room?
- A. H#S impacts gas-based fire suppression system operation
- B. H#S impacts the static properties of the floor
- C. H#S can cause corrosion which impacts reliability of equipment
- D. There is no risk
Answer: C
Explanation:
Hydrogen sulfide (H#S) is a corrosive gas that readily reacts with metals, especially copper and silver found in circuit boards, connectors, and power supply components. Even at concentrations below human detection thresholds, H#S can cause sulfidation corrosion leading to intermittent connections, failure of solder joints, and increased failure rates of electronic equipment.
ASHRAE Technical Committee 9.9 has documented multiple failures in data centers due to corrosive gases (notably sulfur-bearing compounds). Therefore, high humidity combined with H#S presence accelerates this risk.
H#S does not affect static flooring properties (B) or fire suppression agent chemistry (D). Option A is clearly incorrect as the risk is well-documented.
References: ASHRAE TC 9.9 "Particulate and Gaseous Contamination Guidelines" (2011), IEC 60721-3 (Environmental Classification).
NEW QUESTION # 76
Should aerosol cleaning solutions be used in the computer room?
- A. Yes, if not connected to power
- B. No, unless leak detection installed
- C. No, it will contaminate the room
- D. Yes, only if room smells bad
Answer: C
Explanation:
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.
References: ASHRAE TC 9.9 "Contamination Guidelines," NFPA 75 §8.4.
NEW QUESTION # 77
Which formula is correct for a three-phase system?
- A. Phase-to-Phase Voltage = Phase-to-Neutral Voltage ÷ 1.732
- B. Phase-to-Phase Voltage = Phase-to-Neutral Voltage × 1.732
- C. Phase-to-Phase Voltage = 1 # (Phase-to-Neutral Voltage × 1.732)
- D. Phase-to-Phase Voltage = 1 # (Phase-to-Neutral Voltage ÷ 1.732)
Answer: B
Explanation:
For balanced three-phase systems: where .
References: IEC 60038 (standard voltages), any power systems fundamentals text.
NEW QUESTION # 78
Management requests a 15-minute battery bank at full UPS load. UPS specs:
* 30 kVA, PF 0.8
* Battery 384 V (192 cells), end discharge 308 V
* Inverter PF 0.8, 400 V output
What information is missing to perform the calculation?
- A. Inverter efficiency / output PF
- B. UPS efficiency
- C. Available battery charging current
- D. Load imbalance
Answer: B
Explanation:
Battery sizing requires determining the real power demand of the UPS. With 30 kVA at 0.8 PF, the real load is 24 kW. To calculate required ampere-hours for 15 minutes of runtime, we need:
Where P = load, t = runtime, V = battery voltage, and # = UPS efficiency.
Without UPS efficiency, we cannot know actual DC load on the batteries. A UPS with 90% efficiency will require more battery capacity than one with 95%. None of the other listed parameters (PF, imbalance, charging current) are critical for runtime capacity calculation.
References: IEEE Std 1188 (VRLA Batteries), IEC 62040-3 (UPS performance), ANSI/TIA-942-B §6.2.
NEW QUESTION # 79
What is the redundancy setup shown in the diagram?
- A. 2+N+1
- B. 2(N+1)
- C. N+N+N
- D. N+2
Answer: D
Explanation:
The diagram shows three UPS modules, each 100 kW, connected in parallel to support a 100 kW IT load.
That means:
* One module (100 kW) can support the load (N).
* Two additional modules are installed as redundancy.
This equals N+2 redundancy.
* 2+N+1 and 2(N+1) imply dual active paths not shown.
* N+N+N is not an industry term.
Thus, the correct redundancy level is N+2.
References: ANSI/TIA-942-B §6.2 (UPS Redundancy Models), IEC 62040-3.
NEW QUESTION # 80
You want to make cooling more effective by setting cold aisle temperature to 4 °C (39 °F). Is this acceptable?
- A. No, intake air must be exactly 20 °C (68 °F)
- B. Yes, as long as dewpoint doesn't go below -9 °C (16 °F)
- C. Yes, but only if cooling systems can maintain this continuously
- D. No, 4 °C (39 °F) is below the allowable ASHRAE range
Answer: D
Explanation:
According to ASHRAE TC 9.9 Thermal Guidelines (2016), the recommended intake temperature range for Class A1 ICT equipment is 18-27 °C (64-81 °F). The allowable lower limit is 15 °C (59 °F). Setting supply to 4 °C (39 °F) falls far below these limits.
Operating at such low temperatures would:
* Cause condensation risk when surfaces drop below dew point.
* Create severe energy inefficiency, as chillers would run at extremely low setpoints.
* Possibly damage hardware due to thermal shock.
Options A and B are misleading-system capability or dew point alone does not override ASHRAE guidelines. Option D is incorrect since 20 °C is a common design target, not a requirement.
Thus, supplying 4 °C is not acceptable.
References: ASHRAE TC 9.9 "Thermal Guidelines for Data Processing Environments," ANSI/TIA-942-B §6.
5.
NEW QUESTION # 81
A data center is in an area where utility power is highly available-only a few outages per year, typically <1 hour per event and <50 hours/year not available. What type of generators should be installed?
- A. Continuous generators in at least N+1
- B. Standby generators, ideally in an N+1 configuration
- C. Standby generators; no N+1 needed as the risk of a failure to start is negligible
- D. A combination of standby, prime, and continuous sized to 500% of the load
Answer: B
Explanation:
With infrequent/short outages, Standby (Emergency Standby Power, ESP) generators are appropriate; N+1 mitigates failure-to-start risk and supports concurrently maintainable designs.
References: ISO 8528-1 (generator rating definitions: ESP/PRP/Continuous), ANSI/TIA-942-B §6.2 (electrical redundancy).
NEW QUESTION # 82
What should be implemented when an Inergen-based fire suppression system is installed in the computer room?
- A. Gas tanks need to be within or close to the data center
- B. Proper water leak detection system
- C. Drainage system under raised floor
- D. Pressure release valves in the data center
Answer: D
Explanation:
Inert gas systems (Inergen, Argonite, Nitrogen) extinguish fires by reducing oxygen concentration through massive gas discharge. This rapid release causes a significant pressure rise inside the room. To avoid structural damage to walls, ceilings, or raised floors, pressure relief vents (pressure release valves) must be installed.
* A (drainage) applies to water suppression.
* B (tank location) is logistical but not mandatory; remote storage with piping is acceptable.
* D (water leak detection) is unrelated to inert gas suppression.
Therefore, the critical safety requirement is pressure relief.
References: NFPA 2001 §5.2.1.2 (Pressure Relief), ISO 14520-1 §5.2.
NEW QUESTION # 83
A computer room with raised floor and hot/cold aisles is designed. What is the minimum required distance between the air-conditioner outlet and the first rack?
- A. None
- B. 60 cm (2 ft)
- C. 120 cm (4 ft)
- D. 180 cm (6 ft)
Answer: C
Explanation:
To ensure uniform air distribution, there must be a buffer zone between CRAC/CRAH discharge and the first row of racks. Industry best practice (ASHRAE & TIA-942) specifies at least 1.2 m (4 ft).
* Less than 1.2 m risks air velocity hotspots and turbulence, disrupting cold aisle containment.
* More than 1.8 m wastes valuable floor space without added benefit.
Thus, 120 cm is the recommended minimum.
References: ANSI/TIA-942-B §6.5.3 (CRAC placement), ASHRAE TC 9.9 Thermal Guidelines.
NEW QUESTION # 84
When are the wet bulb and dry bulb temperatures identical?
- A. When the relative humidity is at the best practice value for relative humidity, being 50% RH
- B. When the relative humidity is 100%
- C. When the dry bulb's temperature is at the lowest allowable temperature for IT equipment as per ASHRAE
- D. When the dry bulb's temperature is at the highest allowable temperature for IT equipment as per ASHRAE
Answer: B
Explanation:
The wet bulb and dry bulb temperatures become identical when the relative humidity reaches 100%. At this point, the air is fully saturated with moisture, meaning it can no longer absorb additional water vapor. As a result, the rate of evaporation decreases, and there is no difference between the dry bulb and wet bulb temperatures.
Detailed Explanation:
The dry bulb temperature measures the air temperature, while the wet bulb temperature takes into account the cooling effect of evaporation. When relative humidity is at 100%, the air has reached its saturation point, and no further evaporation occurs. This causes both the wet bulb and dry bulb thermometers to display the same temperature reading. This condition is critical in understanding environmental conditions, particularly in HVAC and data center environments, where humidity control is essential to avoid equipment overheating or corrosion.
EPI Data Center Specialist References:
The EPI Data Center Specialist training includes understanding humidity levels and their impact on data center environments. Knowing when wet bulb and dry bulb temperatures align helps data center operators manage moisture levels effectively, which is essential for preventing issues related to high humidity, such as condensation on IT equipment.
NEW QUESTION # 85
The 'maximum exposed area' of the fire-rated glass is defined by the supplier as 3 sqm/32 sqft. The window area is 4 sqm/43 sqft.
What would be the best option?
- A. Split the window in two equal parts fitted together with transparent silicon glue.
- B. Do not use fire-rated glass due to the size limit and replace it with normal glass.
- C. Split the window into parts smaller than specified as the maximum exposed area and ensure fire-rated frames are used.
- D. Split the window in two equal parts using an aluminum frame.
Answer: C
Explanation:
When the window area exceeds the maximum exposed area specified for fire-rated glass, it is necessary to split the window into sections that comply with the fire rating requirements. This means creating smaller sections that are each within the 3 sqm/32 sqft limit and using fire-rated frames to ensure that the entire assembly meets fire safety standards. This approach maintains the fire-rated integrity of the glass, while allowing for larger window areas.
Detailed Explanation:
Fire-rated glass is designed to contain fire and prevent it from spreading. If the window exceeds the maximum exposed area defined by the supplier, the integrity of the fire-rated glass could be compromised. By dividing the window into compliant sections with fire-rated frames, you ensure that each pane performs as intended in the event of a fire. Fire-rated frames help maintain the fire resistance across the entire assembly, making this option the best for safety and compliance.
EPI Data Center Specialist References:
EPI recommends adhering strictly to fire safety standards, especially when using materials like fire-rated glass. The guidelines emphasize that modifications should always respect the manufacturer's specifications to ensure the system remains effective in containing and preventing the spread of fire.
NEW QUESTION # 86
What is the main disadvantage of using a ToR (Top of Rack) design?
- A. A single ToR (Top of Rack) switch is more expensive than an EoR (End of Row) switch.
- B. A ToR (Top of Rack) switch has only optical interfaces.
- C. You need a separate rack to install all your ToR (Top of Rack) switches.
- D. There will be more switches to manage.
Answer: D
Explanation:
A Top of Rack (ToR) design typically requires more switches because each rack has its own switch to manage network connections, as opposed to End of Row (EoR) or centralized designs, which consolidate switches. While ToR designs improve cabling efficiency and reduce latency, they also increase the number of switches, thus raising management complexity and potentially increasing capital and operational costs.
Detailed Explanation:
In a ToR setup, each rack's individual switch allows for quick access and streamlined cabling within the rack. However, this setup means more devices to configure, monitor, and maintain, which can increase administrative overhead and network management complexity.
EPI Data Center Specialist References:
EPI documentation notes that ToR designs can improve performance but also lead to increased management needs due to the higher switch count, making them less ideal in environments where simplified network management is prioritized.
NEW QUESTION # 87
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