1.
What are the salient differences between Copper and
Aluminum conductor?
Copper
is the commonly used conductor. It has higher conductivity
and heavier compared to Aluminum, and usually costs
more. Although Aluminum has lower cost, greater size
or cables of Aluminum is needed to match the conductivity
offered by copper. Either way the cost offsets.
2.
Do solid conductors have better conductivity than the
stranded ones?
Yes
to a certain extent, although the variation is considered
to be negligible.
The choice would depend on the level of flexibility
needed in the application of wires and cables. Stranded
conductors are more flexible and are more preferred
when applied to winding installation. Due to its lower
flexibility, solid conductors are usually produced
in smaller sizes, e.g. 8 AWG sizes and lower.
3.
What is the importance of insulation in wires and cables?
The
electrical properties of the wires are significantly
influenced by the insulation. High-frequency communication
cables, for example, would have Polyethylene (PE)
as insulation because the capacitance and attenuation
are minimal if this type of thermoplastic were used.
On top of the wire and cable application, factors
such us heat and flame resistance; moisture resistance;
mechanical toughness; resistance to ionization; flexibility;
and the usage life determine the insulation. The other
insulation can be XLPE (chemically cross-linked PE
Compound), Polyvinyl Chloride (PVC), and Ethylene-Propylene
(EP) Rubber.
4.
What are to be considered in selecting wires and cables?
In
selecting a wire, the following should be considered:
Installation
- the area of installation whether indoor, underground,
outdoor or aerial is critical in the choice of wire
because the exposures to various elements may affect
the performance and safety of the wire. This is where
the characteristics of insulation play an important
part.
Voltage
Rating - determines the size of the conductor,
and the thickness and type of insulation.
Conductor
Size – the current load, KVA load, and
kilowatt load are governed by voltage drop besides
the heating and power factors. These must be known
before the conductor size can be determined.
Ampacity
Limitation– the maximum current a wire
or cable can safely carry without exceeding the capacity
of the insulation or jacketed material.
External
Condition - the presence of other sources of
heat located in the installation, such as pipes, corrosive
agents, structural materials, and other cables can
cause increase in the temperature of wire.
5.
How to properly specify an order for wires and cables?
In
ordering wires and cables, the following should be
specified:
Type
of Wire
Size
Number of Conductor (for Multicore)
Voltage Rating
Type of Insulation
Insulation thickness (Insulation Level for Power
Cable)
Type of Protective Covering
Type of Conductor
a.) Copper/Aluminum
b.) Solid or Stranded
Total length/individual cutting length
6.
What are the commonly used lighting and fixtures wire
for residential, commercial, and industrial installation?
TW,
THW, THHN/THWN
wires are most commonly used for lighting and fixture
purposes.
7.
What is the importance of colored insulation?
The
color of the insulation serves as a guide in circuit
indentification and for easy wiring connection.
8.
What type of wire is used for extension purposes?
Duracord
and Duplex Cord (SPT)
are used for extension purposes.
9.
What is the recommended wire for outdoor wiring?
For
outdoor wiring, use PE insulated wire because of its
weather-resistant characteristics. On the other hand,
it is recommended to use PVC insulated wire for its
flame retardant properties for indoor wiring.
10.
What are the general characteristics of a safe wire?
A
safe wire must have the following characteristics:
- Right
conductor size
- Proper
thickness of insulation
- Virgin
copper with 99.9% conductivity for copper wiring
- Pure
plastic insulation
- Must
have passed stringent quality control
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