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27 Cards in this Set
- Front
- Back
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What is the ANSI grounding code?
(8-1) |
ANSI 607 B |
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What are the two NFPA standards that discuss grounding and bonding?
(8-1) |
NFPA 70, National Electrical Code
NFPA 780, Lightning Protection Code |
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As it pertains to grounding, what is a primary responsibility of the ITS systems designer?
(8-2) |
Safeguarding personnel, property, and equipment from foreign electrical voltages and currents |
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What are the consequences of improper grounding?
(8-2) |
1. Death or injury due to electrical shock
2. Destruction of electronic equipment due to fire
3. Component malfunction or degradation
4. Work or process disruption |
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When designing grounding systems, the ITS designer must consider the following:
(8-2) |
1. Lightning
2. Ground potential rise
3. contact with electrical circuits
4. EMI
5. RFI
6. EMC |
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True or False: ITS designer are responsible for engineering the portions of the electrical system pertaining to AC electrical ground faults, lightning protection systems, or surge protection.
(8-3) |
False |
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When is the best time to design a bonding, grounding and protection scheme for a structure?
(8-3) |
During the initial planning and construction phases of a project |
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The ITS designer must recognize that the following three subsystems of the grounding and bonding system should be at every site:
(8-4) |
1. AC ground electrode system
2. Equipment grounding system
3. Telecommunications Bonding system |
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What does not provide adequate electrical protection for people and equipment in the event of electrical faults within the premise wiring system?
(8-5) |
AC grounding electrode system |
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Where must the ITS designer specify that the telecommunications busbar be located if the building steel is used as the AC grounding electrode?
(8-6) |
On or as close to a structural steel member as practical within a TR or EF |
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In new construction, who provides facilities to access the grounding electrode system?
(8-6) |
Electrical Contractor |
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What is the recommended maximum current value on a bonding conductor?
(8-7) |
Less than 1.0 ampere for AC, less than 500 milliamperes for DC |
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What is the recommended maximum value for bonding resistance between an available grounding electrode and a busbar in the EF or TR?
(8-7) |
0.1 ohms |
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The impedance of the telecommunications equipment grounding conductor should be as low as possible. IEEE 1100 suggests a maximum value for 120 volt and 277 volt circuits. What are these values?
(8-7) |
1 ohm and 0.8 ohms |
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What is used to measure the impedance telecommunications equipment grounding conductor?
(8-10) |
ground impedance tester |
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What equipment grounding topology reduces the effects of RFI, and EMI on the equipment grounding system?
(8-11) |
Isolated ground (IG) |
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What should be grounded in a raised floor system?
(8-12) |
Every 4th pedestal of the raised floor should be grounded |
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What is the overall purpose of the telecommunications bonding infrastructure?
(8-13) |
to equalize potential differences between metallic surfaces predominantly in event of lighning; AC system faults; EMI induction; or ESD |
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Why are telecommunications bonding conductors installed?
(8-13) |
They are intended to equalize the voltages when a lightning strike or AC ground fault occurs |
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What is the common dimension for a TMGB?
(8-18) |
4" x 1/4" x Variable length; predrilled copper, listed by a NRTL |
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Where should the TMGB be located?
(8-19) |
As near as possible to the telecommunications cable EF |
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The BCT should be as short as possible and never exceed the following length:
(8-19) |
30 feet; there is no reason for this value in the NEC or ANSI |
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Where should the TGB ground reference be?
(8-20) |
to the telecommunications equipment ground terminal of the nearest electrical panelboard to equalize potential between them. |
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What is a TBB?
(8-21) |
A telecommunications bonding backbone conductor is intended to equalize potential between TR on multiple floors with an ultimate connection to the EF TMGB |
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If the bonding conductor does not exceed 100 feet, what size of cable can be used?
(8-22) |
#6AWG; there is no logic to this and is not referenced in NEC or ANSI |
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What is a GE?
(8-22) |
A grounding equalizer conductor is intended to equalize potential between TR on the same floor |
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What is the maximum voltage drop for a bonding conductor along its entire length?
(8-23) |
40 volts |
