A Message from Toronto Hydro:
Dear Toronto Hydro Customer
This is to notify you of an upcoming voltage reduction test planned by the Independent Electricity System Operator (IESO). The test will take place on Tuesday, February 3, 2015 and involves two province-wide voltage reduction exercises. Please see the schedule below:
- A voltage reduction of 3 per cent will occur from 9 a.m. to 10 a.m. EST*.
- A voltage reduction of 5 per cent will occur from 1 p.m. to 2 p.m. EST*.
*EST = Eastern Standard Time
If system conditions are unfavourable on Tuesday, February 3, 2015, this activity will be postponed to Thursday, February 5, 2015.
Under provincial rules, the IESO is required to conduct regular tests of its emergency procedures in order to help ensure staff familiarity and to identify and address any deficiencies. Voltage reduction tests are usually scheduled every 18 months. The most recent system-wide test was performed on July 23, 2013.
Please be aware that some equipment may be sensitive to voltage reductions. It’s important to understand these impacts during a planned test in order to prepare for an actual emergency event. Consider how a voltage reduction might affect escalators, elevators, sensitive electronic equipment, etc.
This exercise will determine the total amount of load reduction attainable in the Toronto area and ensure that the IESO can continue to rely on voltage reductions to manage future emergencies. We encourage customers to use this opportunity to identify and resolve any operational difficulties that they experience as a result of the IESO voltage reductions.
Further information on voltage reductions is available on the IESO website at:
http://www.ieso.ca/Pages/Ontario%27s-Power-System/Reliability/Voltage-Reduction- Tests.aspx.
If you have any questions or concerns, please contact Christine Woon, Customer Care at 416-542-3598 or email This email address is being protected from spambots. You need JavaScript enabled to view it. .