Journeyman Lineman (JL) Verbal Practice Test

In a typical 120/208V three-phase service, each hot leg to neutral is 120V, and the voltage between any two hot legs is 208V. The top-right position on a customer meter panel is conventionally one of the three hot legs, the leg that, when compared to the other two, provides 208V. This 208V between legs comes from the math of a three-phase wye connection: line-to-neutral is 120V, so line-to-line is 120 × sqrt(3) ≈ 208V. The other voltages refer to different systems or conditions—277V to neutral would appear in a 480Y/277V system, 240V is typical for 120/240 single-phase or delta services, and 120V is the leg-to-neutral voltage, not the leg-to-leg voltage. Thus the top-right leg is the 208V leg.