Ch. 9 * (Bonding & Grounding) Flashcards
Safeguard against ___ due to electrical shock
Death or injury
Device used to test the impedance of the equipment grounding conductor
Ground impedance tester
Ground every ___ floor pedestal
4th
Commercial building grounding and bonding standard
607-A
TMGB
Telecommunications Main Grounding Busbar
Minimum dimension of TMGB
.25” X 4”
Ground wire
6 AWG
BCT
30’
Bonding in the EF
Not cold water pipe
TGB dimensions
.25” X 2”
Consider the TBB for a large site may be ___
Costly to achieve
Typical bonding connections
Compression-type
Exothermic welding
Clamps
Visual inspection
Loose connections Corrosion Physical damage System modifications Except "impedance"
Direct-buried cable collects ground strikes within a distance of ___
6.5’ - 20’ determined by soil resistance
Lightning Protection Institute
Based on NFPA 780
NFPA 70
NEC (national electric code)
Standard for installation of lightning protection systems
NFPA 780
Lightning exposure exceptions
Metropolitan
140’ or less
Five or fewer thunderstorms per year
Earth resistivity less than 100 ohm-meters
Distance limitation for 6 AWG
100’
Purpose of grounding
Equalize potentials
SRG
Raised floor (grounding and bonding)
IG
Isolated Ground
IG receptacle
Orange triangle
Bonding
Two metallic items
Water pipes ___ be used as a ground
Should never
IEEE standard for power and grounding
1100
Max DC current on bonding conductor
500 mA
Impedance of the equipment grounding conductor
As low as possible
A primary responsibility of the ITS designer
Safeguarding personnel, property and equipment
