Serving North Texas Since 1937

Attention, animals: Please stay out of our substations!

Attention, animals: Please stay out of our substations!


CoServ is always seeking ways to prevent power outages. And it’s not just lightning, high winds and  ice storms that we have to worry about.

Something as simple as a chicken snake slithering up substation equipment can cause an electrical short that knocks out power for thousands of CoServ Electric Members.

“If it got up on top, it’s definitely going to burn up a bushing or something and cause a big outage,” said Perry Ancell, CoServ’s Systems Operations Superintendent. “More than likely, if it’s just one bay, you’re going to have probably 2,000 to 3,000 people off and if the whole transformer goes bad, we could have 6,000 to 8,000 people out.”

You read correctly: One snake could trigger an outage affecting you and thousands of your neighbors.

This  is why CoServ – with the assistance of our generation and transmission provider, Brazos Electric – has committed to installing “snake fences” at all 29 of our substations. Officially known as animal deterrent systems, these electrified structures will be installed this year at seven substations, with the other 22 phased in over the next few years.

The barriers surround the equipment at the substation and deliver a mild, electrical shock that discourages animals – especially squirrels, raccoons and snakes – from scaling it.

Four gates allow CoServ or Brazos Employees safe access to equipment without deactivating the electrical fence. The modular fence can also be deactivated and a section of it taken down so workers can get a truck, crane or large equipment inside the substation for maintenance.

For more on snake fences, check out CoServ's new podcast, As a Meter of Fact, where we talk to experts about why we need barriers around substation equipment. 


Greg WardSenior Vice President of Field Operations, explains why the snake fence is important and the impact it could have on CoServ’s reliability rating.

Why are these new snake fences a good value?

“Relative to the amount of money that we invest in a substation, it’s a small investment. It’s pennies on the dollar for what we’re after to mitigate that outage or to prevent a potential outage. So, 2020 we could absolutely see a positive impact on our SAIDI score.”

Why are animals such an issue for our electrical infrastructure?

“We’re starting to clear open space land and build homes, which moves all of this wildlife from their current homes and their nesting areas. It disturbs where they’re living.”

Why are snakes attracted to electrical substations?

“It’s the energy in that substation. It’s the heat, it’s the actual vibration of the equipment within the substation that attracts that snake. Also, they’re after birds. So, nesting that occurs from birds in our substation, the snakes are after something to eat.”

Why don’t all utilities install snake fences?

“These are measures in our maintenance program that a lot of for-profit energy companies don’t spend a lot of dollars on. We’re constantly looking for areas to improve with low cost associated with them.”


  1. Weather
  2. Animals
  3. Equipment malfunction
  4. Vehicles hit equipment
  5. Planned outage (for maintenance)


  • Bay - describes a circuit breaker with its associated disconnectors, earth switches, instrument transformers and protection equipment.
  • Bushing - an insulated device that allows an electrical conductor to pass safely through a grounded conducting barrier, such as the case of a transformer or circuit breaker
  • SAIDI - System Average Interruption Duration Index, which measures outage time divided by the number of meters served. For 2019, CoServ had among the best SAIDI scores in Texas at 32.5, meaning the average outage lasted about 32 minutes. 
  • Substation – a crucial part of an electrical generation, transmission and distribution system, used to convert high voltage to low and vice versa
  • Transformer - a passive electrical device that transfers electrical energy from one electrical circuit to one or more circuits


Learn more about these new fences in Episode 1 of our new podcast, As A Meter Of Fact.


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