An EPS grid or plasma grid was a component of the electro-plasma distribution network on Starfleet vessels from the 22nd century onwards. In the event of an emergency, the grid may be shut down to avoid an overload. By the 24th century maintenance was performed on the grid at regular intervals.
In 2151, Lieutenant Malcolm Reed bypassed the EPS grid to receive power from Enterprise NX-01's impulse drive to get the phase cannon online, Trip Tucker denied this possibility, but later allowed it. (ENT: "Silent Enemy")
When the Enterprise crew were locked in their quarters by Suliban forces in 2152, Tucker rerouted the comm signal through the EPS grid, enabling him to talk to anyone on B Deck. (ENT: "Shockwave, Part II")
Not long after, the impact of a Romulan mine caused an overload in Enterprise's EPS grid. (ENT: "Minefield")
Days later, the automated repair station faked a situation in which Travis Mayweather appeared to have died trying to tap into the EPS grid in launch bay 1. (ENT: "Dead Stop")
In August of 2152, while under the influence of radiation emanating from a nearby singularity, Malcolm Reed requested Tucker's assistance in preparing an emergency shutdown procedure for the EPS grid. (ENT: "Singularity")
In 2153, the presence of dark matter caused a surge in the EPS grid aboard an Enterprise shuttlepod. (ENT: "First Flight")
In 2154, following severe damage to Enterprise as a result of a Xindi attack, a surge in the EPS grid on A Deck was reported to Captain Archer only moments before it exploded. (ENT: "Damage")
In 2370, Donald Kaplan jibed Geordi La Forge that by cleaning the USS Enterprise-D's plasma grid they might match the power conversion level aboard Kaplan's vessel, the USS Intrepid. (TNG: "Force of Nature")
In 2371, the magnetic wake produced by space-dwelling lifeforms caused a huge fluctuation in the USS Voyager's EPS grids as it was pulled along. (VOY: "Elogium")