CDCP Exam Dumps - Certified Data Centre Professional (CDCP)

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.

References:

1: CDCP Preparation Guide, page 23, section 2.4.2 2: Signal Reference Grid | Enterprise Data Center Design and Methodology5, page 1, section 1 3: Grounding System Ground Rod Stacking Installation - Rain Bird6, page 1, section 1 4: SmartRack Copper Bus Grounding Bar - Eaton Website7, page 1, section 1

Sprinkler heads used in computer rooms activate at 57 °C (135 °F), which is the standard temperature rating for ordinary sprinklers. This is the temperature at which the heat-sensitive element of the sprinkler head, such as a glass bulb or a fusible link, breaks or melts, allowing water to flow from the sprinkler. Sprinkler heads are designed to activate only when exposed to a fire, not to ambient temperature fluctuations. Therefore, sprinkler heads should be installed at a sufficient distance from the heat sources, such as servers, racks, or ducts, to avoid accidental activation. Sprinkler heads should also be selected and installed in accordance with the relevant standards and codes, such as NFPA 13 and NFPA 75.

References:

1: CDCP Preparation Guide, page 24, section 2.4.3 2: Sprinkler Systems in Data Centers3, page 1, section 1 4: Data Center Fire Protection5, page 1, section 2 6: Data Center Sprinkler System Design7, page 1, section 1

According to the CDCP Preparation Guide1, risk can be defined as the product of impact and probability. Impact is the measure of the negative consequences or losses that may result from a risk event, such as downtime, data loss, or damage to the data centre. Probability is the measure of the likelihood or frequency of a risk event occurring, based on historical data, expert judgment, or statistical analysis. By multiplying impact and probability, risk can be quantified and compared, which helps in prioritizing and mitigating the risks. For example, a risk event that has a high impact but a low probability may have the same risk level as a risk event that has a low impact but a high probability.

References:

1: CDCP Preparation Guide, page 25, section 2.5.1 2: Data center risk assessment: A decision-making tool3, page 1, section 1 4: Accounting for Risk in Your Data Center Design/Build Strategy5, page 1, section 1 6: A Novel Framework for Data Center Risk Assessment7, page 1, section 1

According to the CDCP® Preparation Guide, an audible signaling and notification device is a device that produces a sound to alert or notify the occupants of a data center of an event or condition. Sirens are examples of such devices, as they can emit loud and distinctive tones to warn of fire, emergency, or security incidents. Strobes, on the other hand, are visual signaling and notification devices that produce flashes of light to attract attention or convey information. Alarms and clocks are not specific types of devices, but rather general terms that can refer to various audible or visual devices.

References: CDCP® Preparation Guide, page 30. Audible Visual Notification | System Sensor | Honeywell. Audible-Visual Signaling Devices - AutomationDirect.

According to the CDCP Preparation Guide1, magnetic fields of the type ‘H’ or ‘B’ are created when an electric current flows through a conductor, such as a wire or a coil. The magnetic field strength ‘H’ is proportional to the current ‘I’ and the number of turns ‘N’ of the coil, and inversely proportional to the length ‘l’ of the coil. The magnetic flux density ‘B’ is proportional to the magnetic field strength ‘H’ and the permeability ‘μ’ of the medium in which the magnetic field exists. The greater the current, the stronger the magnetic field and the magnetic flux density. The relationship between ‘H’, ‘B’, ‘I’, ‘N’, ‘l’, and ‘μ’ can be expressed by the following equations:

H = N I / l

B =μH

References:

1: CDCP Preparation Guide, page 23, section 2.4.2.1 2: Difference between B and H in magnetic fields?3, page 1, section 1 4: Magnetic field | Definition & Facts5, page 1, section 1