standards and guidelines for communication sites - Radio And ...

standards and guidelines for communication sites - Radio And ... standards and guidelines for communication sites - Radio And ...

radioandtrunking.com
from radioandtrunking.com More from this publisher
24.12.2012 Views

MINIMUM SITE GROUNDING (EARTHING) REQUIREMENTS CHAPTER 4: EXTERNAL GROUNDING (EARTHING) • Each leg of a self-supporting tower shall be bonded to the tower ground ring using grounding conductors of 35 mm2 csa (#2 AWG) or coarser, bare, solid, tinned, copper conductor. See Figure 4-33. • The tower grounding conductors shall be exothermically bonded to the tower unless specifically directed otherwise by the tower manufacturer. • The tower's support piers (concrete footings) should have the rebar electrically connected to the tower holding bolts (ANSI T1.313-2003, section 10.3.1). • Install radial grounding conductors if needed. See “Radial (Counterpoise) Grounding Conductors” on page 4-24. GROUND RODS EXOTHERMIC WELD OR MECHANICAL CLAMP FLEXIBLE NONMETALLIC CONDUIT MIN. 762 mm (30 in.) FIGURE 4-33 EXAMPLE OF SELF-SUPPORTING TOWER GROUNDING GROUND ROD CONCRETE FIGURE 4-34 EXAMPLE OF MONOPOLE TOWER GROUNDING EXOTHERMIC WELD OR OTHER SUITABLE MEANS GROUND RING EXOTHERMIC WELD OR IRREVERSIBLE HIGH COMPRESSION FITTING 4-52 68P81089E50-B 9/1/05

STANDARDS AND GUIDELINES FOR COMMUNICATION SITES MINIMUM SITE GROUNDING (EARTHING) REQUIREMENTS 4.7.6.2 GUYED TOWERS Guyed towers shall minimally be grounded (earthed) as follows: • The tower shall be encircled by a ground ring (ANSI T1.334-2002, section 5 and MIL-HDBK- 419A). • The tower ground ring shall be installed at least 610 mm (2 ft.) from the tower structure base or footing (ANSI T1.334-2002, section 5.3.1). • The tower ground ring shall be installed in accordance with “External Building and Tower Ground Ring” on page 4-22. • The tower ground ring shall be bonded to the building ground ring in at least two points using a 35 mm 2 csa (#2 AWG) or coarser, bare, solid, tinned or un-tinned, copper conductor (ANSI T1.334-2002, figure 1, and MIL-STD-188-124B). See “External Building and Tower Ground Ring” on page 4-22. • The tower ground ring shall consist of at least two ground rods installed on opposite (diametrically opposed) sides (ANSI T1.313-2003, section 10.3.1; ANSI T1.334-2002, section 5.2; and ANSI/ TIA/EIA-222-F-R2003, section 12). • Ground rods shall meet the specifications and be installed in accordance with “Ground Rods” on page 4-11. • The bottom plate of a guyed tower shall be bonded to the tower ground ring using three equally spaced grounding conductors, or each leg shall be bonded to the tower ground ring using grounding conductors of 35 mm2 csa (#2 AWG) or coarser, bare, solid, tinned copper conductor. SeeFigure4-35. • The tower grounding conductors shall be exothermically bonded to the tower unless specifically directed otherwise by the tower manufacturer. • The tower's support piers (concrete footings) should have the rebar electrically connected to the tower holding bolts (ANSI T1.313-2003, section 10.3.1). • Install radial grounding conductors if needed. See “Radial (Counterpoise) Grounding Conductors” on page 4-24. EXOTHERMIC WELD OR 12-TON MECHANICAL CRIMP GROUND ROD FIGURE 4-35 EXAMPLE OF GUYED TOWER GROUNDING CONCRETE GROUND RING EXOTHERMIC WELD OR IRREVERSIBLE HIGH COMPRESSION FITTING 68P81089E50-B 9/1/05 4-53

MINIMUM SITE GROUNDING (EARTHING) REQUIREMENTS CHAPTER 4: EXTERNAL GROUNDING (EARTHING)<br />

• Each leg of a self-supporting tower shall be bonded to the tower ground ring using grounding<br />

conductors of 35 mm2 csa (#2 AWG) or coarser, bare, solid, tinned, copper conductor. See<br />

Figure 4-33.<br />

• The tower grounding conductors shall be exothermically bonded to the tower unless specifically<br />

directed otherwise by the tower manufacturer.<br />

• The tower's support piers (concrete footings) should have the rebar electrically connected to the<br />

tower holding bolts (ANSI T1.313-2003, section 10.3.1).<br />

• Install radial grounding conductors if needed. See “Radial (Counterpoise) Grounding<br />

Conductors” on page 4-24.<br />

GROUND RODS<br />

EXOTHERMIC WELD<br />

OR MECHANICAL CLAMP<br />

FLEXIBLE NONMETALLIC CONDUIT<br />

MIN. 762 mm (30 in.)<br />

FIGURE 4-33 EXAMPLE OF SELF-SUPPORTING TOWER GROUNDING<br />

GROUND ROD<br />

CONCRETE<br />

FIGURE 4-34 EXAMPLE OF MONOPOLE TOWER GROUNDING<br />

EXOTHERMIC<br />

WELD OR<br />

OTHER SUITABLE<br />

MEANS<br />

GROUND RING<br />

EXOTHERMIC<br />

WELD OR<br />

IRREVERSIBLE HIGH<br />

COMPRESSION FITTING<br />

4-52 68P81089E50-B 9/1/05

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!