Underground wiring is widely implemented by drilling contractors all around the world for burying cables – as the name implies – under the ground. They are preferred in situations where overhead cables are not feasible to implement, especially in heavily populated areas. This document by We-Bore-It explains various advantages and disadvantages of underground wiring system and the different installation methods used for it.

1. Importance of
Underground Wiring
System

2. Importance of Underground Wiring System
Underground wiring has been in practice since several years – be it for traffic
control systems, relocations, or CCTV surveillance systems. Today, every
construction project prefers underground wiring solutions because of its
minimized impact on the environment, and the site looks neat and uncluttered
as well.
Underground wiring or undergrounding basically involves replacement of
overhead cables with underground cables. They are mainly used for
applications where using overhead cables is not feasible, especially in
factories and densely populated areas. There are different methods to carry
out underground wiring - all of them implemented by companies with
expertise in boring and drilling services.
Apart from the visual and environmental aids, there are other advantages of
underground wiring system that are highlighted below.
Advantages
• Transmission loss is highly reduced
• System can absorb emergency power loads
• Maintenance cost for underground system is comparatively less
• Re-engineering of the setup to emit lower electromagnetic field is
possible, thus, shielding the surrounding area

3. Importance of Underground Wiring System
• System does not emit electric fields
• Area of land required for installation is less
• Extreme weather conditions do not affect the wiring system, that is, it
is less prone to damage and destruction
• Possess no harm to wildlife or low-flying aircrafts
• Underground installation reduces the risk of theft, sabotage, or illegal
connections
• Environmental benefits, like growing trees on the sidewalk, can be
reaped by burying the utility lines
• Underground cables require a surrounding strip of around 1-10 m
whereas an overhead cable uses about 20-200 m for the same
Even though the advantages of an underground wiring system outweigh the
disadvantages, they need to be enlisted.
Disadvantages
• The cost of underground wiring is greater than overhead power lines.
Moreover, the overall lifecycle cost of underground is more than that of
overhead setup.
• Underground repairs sometimes may take weeks for accomplishment.
Overhead wiring system, on the other hand, are easy to track and repair
(within few hours).

4. Importance of Underground Wiring System
• Uprating of underground lines is not possible, whereas, overhead lines
can be modified easily.
• The location of underground cable is not easily identifiable, increasing
the risk of wiring damage and electrocution of the workers.
Types of Installation methods
1. Open-cut method
• Direct burial
As the name implies, direct burial involves digging up the
sidewalk or the first traffic lane; burying the cables in it; restoring
the surface. This method facilitates heat dissipation; hence, less
derating of cables. It is the quickest and cheapest approach, but the
system is prone to physical damage.
• Semi-direct burial
This technique is similar to direct burial but offers more protection
from physical damage. The cables run through HDPE conduits,
making it easier to replace or add cables.
2. No-dig method
• Horizontal Directional Drilling (HDD)
HDD is similar to semi-burial technique in terms of protection and

5. Importance of Underground Wiring System
cable requirement. However, the construction cost incurred is
more than other methods. HDD technique involves usage of a
drilling machine which is placed at one end of the area to be dug.
A conduit is used to pull cables through the hole.
• Pipe Jacking
A hydraulic pipe jacking machine is used to push a steel pipe
through the other end of the stretch to be dug. Next, conduits are
pulled through the pipe and the remaining empty space is filled
with mortar. At last, cables are pulled through the conduit. Pipe
jacking offers maximum protection, but is also the most expensive
technique for construction purpose.