Can other circuits interfere with the hearing aid set on the ‘T’ position?
Hearing aid users (with hearing aid on the ‘T’ position) may hear magnetic interference from electrical equipment and wiring, such as fluorescent lights, light dimming circuits or 3 phase power cables. In extreme cases this manifests itself as a continuous loud hum or buzz. Clearly this is unacceptable for the hearing aid user. It is important that any site allocated for an induction loop system is checked for electro-magnetic background interference (in accordance with BS6083 Part 4). It is advisable that test is carried out before the equipment is fitted. A Field Strength Meter (FSM) is used for the purpose of testing for electro-magnetic background interference. An induction loop system must not be installed or be in use if the electro-magnetic background interference exceeds the critical level of -20dB across the majority of the loop area.
