# The Meters (Certification) Regulations 1998, Paragraph 10: Insulation property test

Extent: E+W+S

Each meter shall be tested to demonstrate that the insulation of the meter is of a sufficient standard to enable the meter to operate safely and correctly in the conditions in which it could reasonably be expected to be installed and operated.
TABLE 1
Influence quantities
Reference value
Tolerance
Ambient temperature
Reference temperature or, if not indicated, 23°C.
>15°C to <30°C
Meter position
Vertical
±3°
Voltage
Reference voltage
±1.5%
Frequency
Reference frequency of 50Hz
±0.5%
Voltage and current waveform
Sinusoidal form
Distortion factor <5%
External magnetic induction at the reference frequency (paragraph 5(4))
Zero
Induction value that does not produce a relative error variation of more than ±0.3%
TABLE 2
Test load in terms of marked current
Test number and load
Power factor
Basic/maximum
Maximum continuous
Long range
Short range
Meter type
Polyphase meter load
1 (high)
1
Imax
100%
100%–200% (Note 1)
100%–125% (Note 1)
Single and polyphase
Balanced
2 (intermediate)
1
Ib or 125%Ib
Any load between 25%–75% of the value specified for test number 1 (Note 1)
Single and polyphase
Balanced
3 (low)
1
5%Ib
1.67% (Note 2)
5%
5%
Single and polyphase
Balanced
4 (inductive)
0.5 (Note 3)
Ib or Imax
100%
The same value selected for test number 1
Single and polyphase
Balanced
5 (element)
1
Ib
100%
The same value selected for test number 1
Polyphase
One phase loaded in turn
6 (inductive) (element)
0.5 (Note 3)
Ib
100%
The same value selected for test number 1
Polyphase
One phase loaded in turn
7 (starting-current)
1
0.5%Ib to 1.0%Ib
0.5% to 1.0%
0.5% to 1.0%
0.5% to 1.0%
Single and polyphase
Balanced
Note 1 Where a range is given, any value within that inclusive range may be selected.
Note 2 For maximum continuously rated prepayment meters, the low load test value may be twice the value shown.
Note 3 For test numbers 4 and 6, the inductive power factor shall be between 0.45 and 0.55 inclusive.

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Source: https://www.legislation.gov.uk/uksi/1998/1566/schedule/1/paragraph/10 (the official version)
Page: https://openlegislation.uk/meters-certification-regulations-1998/schedule-1/paragraph-10
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.