Overhead vs. Underground Construction
When it comes to getting electric services to your development or build site, there are many factors to consider when deciding whether to construct distribution lines overhead or underground. Determining which type of construction is the better approach requires consideration of the development area, costs, appearance, reliability, maintenance, and future upgrades.
Overhead Construction
With this type of construction, utility poles are set, wires are strung and equipment such as transformers, fuses, and reclosers are installed.
Pros:
- Lower cost – less expensive to construct, repair and upgrade
- Quicker construction – since no trench is required construction can be done relatively quickly
- Easier to troubleshoot – when overhead, the entire line can be seen making it easier to spot potential problem areas or outages
- Shorter outages – when overhead, the outage can be identified easier and repairs can be made quicker
- Lower contributions for construction - if required at all
- Poles can be multi-purpose – street lighting and security lighting can be added to poles
Cons:
- More susceptible to outage events – bad weather, high winds, vehicle accidents, tree limbs, etc.
- Not as aesthetically pleasing – poles, wires, and equipment can be unattractive and obstructive to views
- More vulnerable to blinks – tree limbs, fallen limbs, and animals can cause temporary interruptions
- More vulnerable to damage – outage events can cause broken poles or downed lines
Underground Construction
Construction of lines underground requires digging a trench deep enough to keep lines away from the surface. Wires are placed in conduits for protection, laid in the trench, the trench is filled in and equipment such as padmount transformers are installed as needed.
Pros:
- Less vulnerable – no interruptions caused by tree branches and wind exposure
- Less susceptible to vehicle accidents – much fewer outages caused by vehicle collisions
- More aesthetically pleasing – infrastructure is out of sight and less obstructive to views
- Less vulnerable to blinks – there’s no exposure to tree branches and fewer interruptions are caused by animals
- Less exposure to energized parts – infrastructure is buried and access is limited
Cons:
- Higher cost – more expensive to construct, repair and upgrade
- Longer construction – trenching is required which could cause delays in construction
- Harder to troubleshoot – damage or faults are difficult to pinpoint
- Longer outages – repairs could take weeks to months to complete
- Contributions for construction – typically underground requires a financial contribution from the contractor or developer
- Susceptible to flooding – lines can become submerged in flood water or exposed from washout
- Vulnerable to excavation – dig-ins are the number one cause of infrastructure damage
- Incur additional fees – street lighting and security lighting can require additional fees
- Majority fed by overhead lines – at some point underground must be connected to overhead lines
