Union CountyPower Outage History
What this grade means
Better than average — fewer or shorter outages than most counties. This county's outage history is better than the national median: recorded outages are less frequent and/or shorter in duration than a typical US county experienced over the same 12-year period. It isn't in the top tier nationally, but its track record points to lower-than-average outage risk.
Outages by year
Outages by month (seasonality)
Worst outage events on record
| Date | Duration | Customers affected | Cause |
|---|---|---|---|
| Sep 27, 2024 | 250 hrs | 3,866 (10%) | Thunderstorm Wind |
| Oct 4, 2025 | 2 hrs | 1,822 (5%) | Unnamed event |
| Aug 30, 2025 | 11 hrs | 1,820 (5%) | Unnamed event |
| Aug 5, 2025 | 2 hrs | 1,669 (4%) | Unnamed event |
| Jan 7, 2018 | 1 hrs | 1,421 (4%) | Unnamed event |
Was There an Outage on a Specific Date?
Pick a date to see whether a power outage was recorded for Union County, South Carolina that day.
Over the 11 years from 2015 to 2025, Union County recorded 155 distinct power outage events, averaging 4.0 hours per event.
The single worst outage on record in Union County started September 27, 2024 (Thunderstorm Wind), lasting 250 hours and leaving up to 3,866 customers without power (10% of the county) at its peak.
June has historically been the worst month for outages in Union County, with 23 events recorded during that month across the dataset.
Based on this history, Union County earns a Reliability Grade of B, placing it in the 80th percentile nationally for grid reliability (higher percentile = more reliable).
Similar counties in South Carolina
Counties with the closest reliability grade and national percentile to Union County.
| County | Grade | National percentile |
|---|---|---|
| Orangeburg County | B | 80th |
| Richland County | B | 76th |
| Kershaw County | A | 83rd |
| Horry County | B | 76th |
| York County | A | 84th |
Most reliable counties nationally
The top 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | South Dakota | A | 100th |
| Clearwater County | Minnesota | A | 99th |
| Limestone County | Alabama | A | 99th |
Least reliable counties nationally
The bottom 3 counties nationally by reliability grade and percentile.
| County | State | Grade | National percentile |
|---|---|---|---|
| Clay County | West Virginia | F | 0th |
| Lincoln County | West Virginia | F | 0th |
| Cameron Parish | Louisiana | F | 0th |
FAQ
How often does power go out in Union County?
Between 2015 and 2025, Union County recorded 155 outage events, averaging 4.0 hours each.
What is Union County's reliability grade?
Union County has a Reliability Grade of B, in the 80th national percentile.
What was the worst power outage in Union County?
The worst outage on record started September 27, 2024 (Thunderstorm Wind), lasting 250 hours and affecting up to 3,866 customers.