Major Initiatives

Major Initiatives

Underground Direct Buried Distribution

Since 2007, we’ve been aggressively replacing all underground direct buried unjacketed cable - cable that was manufactured without an outer protective layer and was not enclosed in ducts before it was buried.  We estimate that problems with underground direct buried cable account for about half of our outages in the underground system.  More than 1,000 kilometres (km) of cable is scheduled for replacement over the next ten years.

Underground Distribution System Rehabilitation

Over the next ten years, we will concentrate on replacing underground cable in areas served by the Underground Distribution System. This project primarily targets areas within the downtown core. The work entails replacing underground cable that is in duct and demonstrating signs of degradation.

Overhead Distribution Project

We're continuing to invest in our aging overhead systems, particularly the 4.16 kilovolts (kV) and 13.8 kV plant. To accommodate the City’s load growth, we will begin rebuilding and converting these systems to 13.8 kV or 27.6 kV. Converting to a higher voltage reduces the amount of line loss and is intended to improve system performance which ultimately affects customer service.

Transformer Stations

We're making considerable investments at transformer stations where we receive electricity supply from Hydro One. We will be replacing the older vintage breakers with the intent of improving reliability.

Municipal Substations

We’re replacing the station class (large) transformers in our municipal substations. This replacement is on a prioritized basis that includes many factors such as age, physical condition, oil quality and past performance. Toronto Hydro proactively monitors the condition and performance of equipment to predict its remaining useful life.  This helps to ensure we maintain or replace equipment at the most optimum point.


Our standardization portfolio includes upgrading or replacing distribution system components and legacy assets that are no longer current.  This includes remedial work for contact voltage and the replacement of handwell lids.

Downtown Reliability

Outside of the former City of Toronto area, the distribution system is an open loop design.  This design incorporates many ties between feeders, including feeders coming from different stations.  We’re adopting this design downtown to allow one substation area to pull supply from an adjoining substation area. This investment provides an alternative supply to the customer. 

Feeder Reliability

The intent of the Feeder Reliability program is to help improve system reliability by making immediate adjustments to feeders that are experiencing a higher than average number of outages.

Secondary Upgrades

Secondary distribution system assets endure wide temperature variations as well as water and contamination.  These elements can lead to the corrosion and eventual degradation of these assets. Over time, this degradation can cause electrical connections to become loose or exposed.  This is why we’re investing in secondary asset installations, repairs and/or upgrades to help ensure that functional and operational performance is maintained.

Rear Lot Rebuild

Backyard distribution equipment has provided reliable service to customers for many years.  Today this equipment is nearing its end-of-life criteria and it’s becoming more difficult to maintain, repair and replace these assets.  The most challenging issue is the accessibility to customer backyards which makes repairs inefficient, costly and unsafe.

Lead Cable

Within the Toronto Hydro distribution system, there's approximately 1,300 circuit km of paper insulated lead-covered underground cables.  This investment is required to replace lead cable primarily in the downtown core to improve safety and environmental conditions and help reduce maintenance costs.  These cables are being phased out globally.

Overhead System Rebuild

There are approximately 400 km of overhead circuits within the Toronto Hydro distribution system.  It's assumed that approximately 75 per cent of these circuits have a box construction design which is obsolete and difficult to maintain.  We’re modernizing and upgrading the existing system with the intent to improve safety and reduce maintenance costs.