Paragraph 1 Pre-heatingI1

The following tests shall not be carried out until the voltage circuits of meters under test and the voltage circuit of working standard integrating meters have been energised for a period of one hour or half an hour if a current of not less than either 10% of basic current or 5% of marked current is applied to the current circuit of the meters, save that the non-registration and starting current tests may be carried out during the pre-heating period.

Sub-paragraph (1) shall not apply to a meter which the examiner is satisfied is capable of full operation as soon as it is energised.