EXIN EXIN Certifications CDCP Questions & Answers

• Question 41:

  Which type of copper wire is used for grounding the racks to the SRG?

  A. Thin copper cable to keep the cost low for grounding.

  B. Thick copper cable to create better grounding.

  C. Braided copper wire or flat copper strip.

  D. Copper cable with plastic insulation (isolation).

  Correct Answer: C

  The type of copper wire that is used for grounding the racks to the SRG (signal reference grid) in a data centre is braided copper wire or flat copper strip, according to the CDCP Preparation Guide1 and various web sources234. Braided copper wire or flat copper strip are preferred over thin or thick copper cable for grounding purposes, because they havelower impedance and higher surface area, which allow better dissipation of electrical noise and interference. Moreover, braided copper wire or flat copper strip are more flexible and durable than copper cable, which make them easier to install and maintain. Braided copper wire or flat copper strip should be connected to the SRG using exothermic welding or other code-compliant methods, and should follow the relevant standards and codes, such as ANSI/TIA/EIA-607 and NFPA 70.

• Question 42:

  Which Class of Fires involves cooking appliances?

  A. Class A

  B. Class B

  C. Class C

  D. Class K

  Correct Answer: D

  According to the EPI Data Centre Professional (CDCP? Preparation Guide, Class K fires involve cooking appliances that use combustible cooking media such as vegetable or animal oils and fats (page 28). Class K fires require special extinguishing agents that can suppress the high-temperature flames and prevent re-ignition. Class K fires are different from Class B fires, which involve flammable liquids such as gasoline, oil, or paint.

• Question 43:

  Starting from which Rating does the requirement of Concurrently Maintainability becomes relevant?

  A. Rated-4

  B. Rated-3

  C. Rated-2

  D. Rated-1

  Correct Answer: B

  The requirement of Concurrently Maintainability becomes relevant starting from Rated-3, according to the Uptime Institute Tier Classification System1. Concurrently Maintainability means that any component or system in the data centre can be maintained or replaced without affecting the availability of the IT equipment. This requires having redundant capacity components and multiple independent distribution paths serving the IT equipment. Rated-3 data centres are designed to achieve Concurrently Maintainability and have a minimum uptime of 99.982%. Rated-4 data centres also have Concurrently Maintainability, but they also have Fault Tolerance, which means that they can withstand any single unplanned event without affecting the availability of the IT equipment. Rated-4 data centres have a minimum uptime of 99.995%. Rated-1 and Rated-2 data centres do not have Concurrently Maintainability, as they have only one distribution path serving the IT equipment and no redundant capacity components. Rated-1 data centres have a minimum uptime of 99.671% and Rated-2 data centres have a minimum uptime of 99.741%.

• Question 44:

  Which type of Fire Detection Device is recommended for protecting a Data Center?

  A. Heat detector

  B. Smoke detector

  C. Flame detector

  D. None of the above

  Correct Answer: B

  According to the CDCP?Preparation Guide, smoke detectors are the most common type of fire detection devices used in data centers, as they can detect a fire in its early stages and provide early warning to the occupants and authorities. Smoke detectors can be either spot-type or air-aspirating, depending on the design and goals of the data center. Spot-type detectors are inexpensive and simple, but may cause activation delay and false alarms. Air-aspirating detectors are more sensitive and reliable, but may require more maintenance and installation costs. Both types of detectors should be installed in accordance with the relevant standards and codes, such as NFPA 72 and EN 54.

• Question 45:

  Which Class of Fires involves energized electrical equipment?

  A. Class A

  B. Class B

  C. Class C

  D. Class K

  Correct Answer: C

  Class C fires involve energized electrical equipment, such as computers, servers, switches, cables, and wiring. These fires require the use of non-conductive extinguishing agents, such as carbon dioxide, dry chemical, or clean agent, to prevent electrical shock and damage to the equipment. Water-based extinguishers, such as Class A or K, are not suitable for Class C fires, as water can conduct electricity and cause electrocution or short circuits.

• Question 46:

  When having two non-synchronized power sources, the ATS / STS need to be of the type:

  A. Break before make.

  B. Make before break.

  C. Both make before break or break before make can be used.

  D. Both an ATS and STS can never handle two non-synchronized sources.

  Correct Answer: A

  When having two non-synchronized power sources, the ATS / STS need to be of the type break before make, which means that the switch disconnects from one source before connecting to the other source. This prevents any short circuit, back feed, or phase mismatch that could occur if the two sources were connected simultaneously. Break before make switches are also known as open transition switches, because they create a brief interruption in the power supply during the switching process. This interruption is usually acceptable for most ICT equipment, as they have internal power supplies or batteries that can handle the transient. However, if the interruption is not acceptable, then the two power sources need to be synchronized before switching, which requires a make before break switch, also known as a closed transition switch. Make before break switches connect to the second source before disconnecting from the first source, which ensures a seamless transfer of power without any interruption. However, make before break switches require that the two sources have the same voltage, frequency, and phase, which can be achieved by using a synchronization module or a phase-locked loop.

• Question 47:

  Which one of the following is a core objective of a Business Value in an organization?

  A. Reducing Costs

  B. Reducing the Deficit

  C. Increasing Sales

  D. None of the above

  Correct Answer: D

  According to the EPI Data Centre Professional (CDCP? Reference Materials, a core objective of a Business Value in an organization is to create value for customers and stakeholders. This means delivering products or services that meet or exceed customer expectations, while also generating profits or benefits for the organization and its shareholders. Reducing costs, reducing the deficit, and increasing sales are possible ways to achieve this objective, but they are not the core objective itself.

• Question 48:

  What is a requirement for both CCTV cameras and recording equipment?

  A. They must be of the same brand.

  B. Both must be placed inside the Computer room.

  C. Both must be connected to a UPS.

  D. CCTV cameras can only be used to cover the outside of the building, where as the recording equipment needs to be located in a secure area.

  Correct Answer: C

  A UPS (Uninterruptible Power Supply) is a device that provides backup power to electrical equipment in case of a power outage or fluctuation. A UPS is essential for both CCTV cameras and recording equipment, as it ensures that the surveillance system can continue to operate and record without interruption or data loss. A UPS can also protect the CCTV cameras and recording equipment from damage caused by power surges or spikes. Connecting both CCTV cameras and recording equipment to a UPS is a requirement for data centres, as it enhances the security and reliability of the surveillance system.

  References: Technical Specification - GeM, [What is a UPS? | Uninterruptible Power Supply | APC by Schneider Electric], [Why You Need a UPS for Your CCTV System - CCTV Camera World].

• Question 49:

  What is the most preferred unit of measure for cooling capacity?

  A. Ton

  B. Watt

  C. BTU

  D. Horsepower

  Correct Answer: B

  Cooling capacity is the measure of a cooling system's ability to remove heat from a space. The most preferred unit of measure for cooling capacity is watt (W), which is the SI unit for power. Watt is defined as the amount of energy transferred or converted per unit time. One watt is equal to one joule of energy per second. Using watt as the unit of measure for cooling capacity allows for easy comparison and calculation of the cooling performance and efficiency of different cooling systems.

  Other units of measure for cooling capacity are ton, BTU, and horsepower, but they are less common and less convenient than watt. Ton is a unit of measure that describes how much water at freezing temperature can be frozen in 24 hours, equivalent to 3.5 kW or 12,000 BTU/h. BTU (British Thermal Unit) is a unit of measure that describes the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit, equivalent to 0.293 W. Horsepower is a unit of measure that describes the rate at which work is done, equivalent to 746 W.

• Question 50:

  is the degree to which a system or component is operational and accessibility when required for use.

  A. Scalability

  B. Agility

  C. Reliability

  D. Availability

  Correct Answer: D

  Availability is the degree to which a system, product or component is operational and accessible when required for use. It is one of the attributes of reliability, which is the ability of a system or component to perform its required functions under stated conditions for a specified period of time. Availability can be calculated as the ratio of the expected value of the uptime (the time when the system is functional) to the total time (uptime plus downtime) of a system or component. Availability can also be influenced by factors such as maintainability, fault tolerance, redundancy, diagnostics, and logistics.

  References: EPI Data Centre Professional (CDCP? Preparation Guide, page 8; Availability - Wikipedia; Reliability - ISO 25000.