Ask Robus: Still calling it “Sustained Emergency”? PSSST, you might be showing your age!Still calling it “Sustained Emergency”? PSSST, you might be showing your age You might still spot “sustained” on older drawings or in manufacturer literature. It once described fittings that ran on a mains supply and continued on battery during a power failure. Older sustained emergency fittings used two separate light sources—one for mains operation and ...The post Ask Robus: Still calling it “Sustained Emergency”? PSSST, you might be showing your age! appeared first on Professional Electrician.