3. When any radio-frequency heating apparatus is used in the British Islands on or after the 21st October 1972 it shall comply with the following requirements for the purposes of section 10 of the Act:
(a)the field strength of electro-magnetic energy radiated in any direction from the apparatus, as measured and computed in accordance with Regulation 5 shall not exceed the limits specified in columns 1 and 2 of Schedule 1 at any frequency within the range from 150 kilohertz to 1000 megahertz, but if the apparatus causes undue interference with any wireless telegraphy used for the purposes of any safety of life service or for any purpose on which the safety of any person or of any vessel, aircraft or vehicle may depend, the limits specified in columns 1 and 4 of Schedule 1 shall apply, and
(b)the terminal voltage, as measured and computed in accordance with Regulation 5 shall not exceed the limits specified in columns 1 and 3 of Schedule 1 at any frequency within the range from 150 kilohertz to 30 megahertz but if the apparatus causes undue interference with any wireless telegraphy used for the purposes of any safety of life service, or for any purpose on which the safety of any person or of any vessel, aircraft or vehicle may depend, the limits specified in columns 1 and 5 of Schedule 1 shall apply.
4. Any radio-frequency heating apparatus which obtains its electric power from any supply to which dwelling houses are not also directly connected is exempt from the provisions of Schedule 1 Columns 3 and 5