1. Some generators even when working at high voltage are factory set to sense at lower voltages. Remember to set the DIP SW 2 to the sensing voltage not the working voltage of the generator even do sometimes it can be the same. 2. If you have a 480/277V generator but you have the sensing wires C and A connected to 240 Volts move DIP SW 2 to ON Another example are rental units with multi-voltage output with a switches for Y, YY, & ZZ output, but sensing is always at 240V from T7 and T9 even though the generator is running sometimes at 480/277V. 3. All voltage readings are to be taken with an average-reading voltmeter Meggers and high-potential test equipment must not be used. Use of such equipment could damage the AVR. 4. Improper setting of under-frequency protection could cause the output voltage of the un Colour:As Shown Material:Metal + Plastic Package Contents: 3 x Automatic Voltage Regulator Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.