over the region of the three coils affects the scs and ic in different directions causing a large change in s 1 s 3 and s 2 s 3 fig4 shows electronic circuitry constituting a read out system for a three coil configuration such as that of fig4 and 44 the circuitry may be similar to that shown in fig4 5 with potentially multiple ratios s 1 s 2 s 2 s 3 and s 1 s 3 being calculated and used for interference detection the meters disclosed herein may be used for current sensing in other types of electrical cables such as lamp cords and round cables in the case of the one coil and two x coil meters a second smaller and deeper groove may be used to locate the lamp cord and in the case of the two y coil meter the lamp cord could be positioned approximately at the center of the gap 44 in both cases the wire separation must be known a selector switch may be used to switch between use with lamp cords and other cables such as nm measuring the current in a round cable is complicated by the constantly changing cross sectional relationship of the twisted together conductors 12 one general approach is for the meter to be capable of latching a maximum reading occurring over a short period of time e g several seconds and to move the meter relative to the cable or vice versa to ensure movement through the maximum flux position of fig1 3 for example the meter may be rotated by at least 90 u00b0 around the cable axis to find the maximum reading alternatively the meter can be moved along.