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Quality Grounding

The Cell Site A Brief Overview

Developed by Ted J. Pappas

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National Electric Code (NEC) National Fire Protection Association (NFPA 70)

The NEC is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. The NEC, while having no legally binding regulation as written, can be and often is adopted by states, municipalities and cities in an effort to standardize their enforcement of safe electrical practices within their respective jurisdiction. The Law………. In some cases, the NEC is amended, altered and may even be rejected in lieu of regional regulations as voted on by the governing bodies of any given locale.

“Code Compliance”

Ted J. Pappas

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A Ground, or Earth, is the reference point in an electrical circuit from which voltages are measured and is a common return path for electric current as well as a direct physical connection to the Earth.

What is a GROUND?

Effects of a poor ground connection

Indictors (alarms) not operating properly

Motor issues

Cooling fans not turning to speed resulting in

improper design cooling

Increased power consumption on site Electrical shock Hazard-----Death

Ted J. Pappas

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Ground Rings

• The ring ground will usually encircle the entire cell

site / building that it is trying to protect.

• The ring ground is used as the base of the entire cell

site’s / building's ground system, and all components

of the building's ground system, including the cell site

/ building structure, are connected to the ground ring.

• The National Electrical Code specifies that ring

grounds must be constructed from #2 or thicker wire,

must be buried at least 2 1/2 feet underground, and

must have at least 20 feet of exposed copper to

ensure good electrical contact with the earth

Ted J. Pappas

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Halo Grounds

• A halo ground is a type of ring ground that, instead of

being installed outside and underground, is installed

inside, near the top of a building or structure.

• The ground reference for all equipment inside the

area being protected is separate from the halo. The

halo is connected to the main building ground, which

may include an underground ring ground outside the

building, with vertical conductors especially in the

corners of the building.

• The halo may be connected to structural metallic

elements such as door frames, building steel, window

frames, and air conditioning vents.

• A typical halo ground is constructed of #2 insulated

copper wire and is installed six inches below the

ceiling, and entirely encircles the area that it is

protecting.

Ted J. Pappas

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Exothermic Welding is known by several naming conventions such

as CADWELD , Exothermic bonding, and thermite welding (TW).

It is a welding process for joining materials that employs molten

metal to permanently join the conductors.

The process employs an exothermic reaction of

a thermite composition to heat the metal, and requires no external

source of heat or current.

Exothermic Welding CADWELD is a Registered Trademark

The Graphite Mold

Ted J. Pappas

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Do I Have The Correct Exothermic Mold?

Inspect the mold ID tag to ensure that it

corresponds to the application, indicated

by the:

1. mold part number

2. conductor size

3. welding material required

4. other materials required

The mold must be correct for the

conductor size and application. DO NOT

MODIFY MOLDS.

Ted J. Pappas

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Cold Welds, also know as “Correct

Compaction” or the Number of

Crimps, are required to prevent

overheating and joint failure.

The FIRST crimp for lugs requiring

multiple crimps MUST be applied at

the “Palm” end of the lug working

towards the end of the Barrel. As it is

crimped the barrel lengthens and is

known as Cold Flow. On a lug that requires only one (1)

crimp the die is centered on the

Barrel

Cold Welds and Lugs

Incorrect Compaction also can result in “shiners”

Ted J. Pappas

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Under and Over Crimping

The cut cross-section of a properly crimped lug to the

left illustrates that all the “Air Voids” have been

removed to form one (1) Mass of Material.

Correct Compaction

The cut cross-section of an Over Crimped lug, also

known as Winging or Flashing, is illustrated to the left.

The common cause of this problem is using a “Die”

that is too small

The resultant is overheating and terminal equipment

failure (under crimping also has the same resultant)

Ted J. Pappas

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An Accurate Crimp?

The ONLY way to truly identify whether a crimp is accurate is to

employ a Vernier Caliper

The measurement is done across the Flats of the Hexagonal Crimp

Note---If the measurement

does not match the

requirement when employing

the correct Die---the crimper

may require calibration

Ted J. Pappas

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Proper Cable Lugging

Step One

Strip the Insulation carefully

not to nick of cut conductors.

Ensure the exact amount of

insulator material is striped

based upon the Lug being

employed

Note a depth gauge tool may be employed

Ted J. Pappas

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Proper Cable Lugging

Step Two

Determine the proper Color-

Keyed Connector for the cable

size being used.

• Connectors marked with just cable size or CU should be used on copper conductors only. • Connectors marked “AL9”* with the cable size should be used on aluminum conductors only. • Connectors marked “AL9CU” with the cable size

may be used on the aluminum or copper conductors

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Proper Cable Lugging

Step Three

Select the proper installation die and appropriate tool

Connectors have colored bands or colored dots that correspond

to color markings on the dies.

Connectors and dies also have a die code number marked or stamped

on them. Dies have a code number engraved in the crimp surface.

Ted J. Pappas

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Proper Cable Lugging Step Four

Locate tool with correct die in proper position on connector and activate

tool.

Remember when making multiple crimps, make the first crimp nearest the

tongue and work towards the barrel end.

When properly crimped, the die code number will be embossed on the

connector for easy inspection to determine if correct die and connector

combination were used.

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Thank You