Which is better, overhead power lines or underground cables?

The electric grid is a generic term for the network in which power is generated, transmitted and distributed to consumers. It is broadly made up of three key components, which are discussed below. To make things a bit easier, we have simpliflied these!

1. Generation: Electricity is produced within generating plants. The Australian Energy Market Commission (AEMC) is a useful resource in locating the plants in which we consumer our electricity within Sydney.
2. Transmission and Distribution: This is the infrastructure which enables electricity to be transported. This is where overhead power lines and underground cables come in typically through power substations, transformer boxes and consumer mains.
3. Consumption: This is the household or commercial consumption of electricity which is then stored at the properties switchboard. 

The electrical grid is an important element in weighing up the benefits between the two, as it determines accessibility. For instance, if there are large natural elements between certain areas, such as mountains and lakes. The transmission and distribution component becomes more complex.

Overhead power lines are the large electrical private power poles you see on pretty much most streets. They come in two types which are timber and galvanised steel poles. From an electrician’s perspective, they are easier to modify and rerouted as the faults are easily identifiable. However, they are subjected to a lot more environmental hazards than their counterparts. Some typical examples that we encounter daily include: tree branches falling onto powerlines, vehicles driving into poles (A Sydney special), storm and wind activity, erosion and animal interference (poor birds and possums). As an overhead power line reaches maturity and the end of its running lifetime, they need to be upgraded and evaluated. This is where the decision to either transition to underground or stay overhead comes into question.

Private Power Pole Defects

A defective overhead power pole will eventually result in you receiving an electrical defect notice.  The main reasons for you receiving this notice is that your electricity connection to the main network has been deemed unsafe by Ausgrid, Essential Energy and Endeavour Energy. You have up to 21-30 days to resolve your defect notice by contacting a private Level 2 ASP electrician, otherwise risk having power being turned off at your property. Specific defect issues that potentially may go wrong with a private power poles include:

• Point of attachment bracket defects 
• Consumer main issues
• Private power pole replacement, repairs or installs
• Upgrading to 3 phase switchboards

Underground cables have become more popular and will continue to take over most streets and suburbs. We have already started to see this push in Sydney. Their aesthetic and their large elimination of environmental hazards makes them safer and attractive. These cables are self-contained underground and are barely noticeable. They are often better suited for highly populated areas, such as major CBDs and residential zones where congestion is a problem. The saved space can be better used for pedestrian crossings and public infrastructure. As well as adding to overall real estate attractiveness of an area.

However, like anything in life, there are drawbacks. Some major limitations of underground cables are the higher upfront costs of installs as they have to be electrically insulated underground. This offers the underground cables protection against moisture and corrosions. There can also be difficulty in locating faults. As the cables are embedded underground, if there is a major problem they may have to be resurfaced. However, this is unlikely as these cables are often brand new. Although they do have a relatively shorter life compared to overhead cables.