2. 2
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
3. 3
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
4. 4
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
5. 5
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
6. 6
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
7. 7
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
8. 8
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
9. 9
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
10. 10
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
11. 11
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
12. 12
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
13. 13
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
14. 14
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.
