To determine the correct phase-rotation relationship, this portableinstrument features construction similar to Phasing Tester H1876-1. Anadditional grounding circuit on the Phase Rotation Tester sets it apartfor the specific purpose named.The probe fittings couple with a high-impedance component encased in each pole. A 22-foot length of insulatedcable stores on the reel affixed to one pole and connects to thevoltmeter on the other pole.