The Seaward Halo Hook on Ammeter for overhead lines is for measuring current flow on overhead line systems up to 40 kV. The sensing unit is encased in moulded plastic and is fully screened against the effects of electrostatic fields. The RMS reading digital display is mounted in the fibre glass tubing body of the instrument and has a measurement range of 0A - 2000A.
Using operator rods the Seaward Halo is hooked over the conductor, after 5 seconds the reading is stored and the instrument can be returned to ground level for the result to be recorded. Typical applications include spot load surveys, phase balancing on primary and secondary circuits, and monitoring of current flow through high voltage fuses to establish their integrity.