The Measuring Instruments (Active Electrical Energy Meters) Regulations 2006

Allowable Errors

3.—(1) The manufacturer shall specify the climatic, mechanical and electromagnetic environments in which the relevant instrument is intended to be used, power supply and other influence quantities likely to affect its accuracy, taking account of the requirements in this Schedule.

(a) Climatic environments—

The manufacturer shall specify the upper temperature limit and the lower temperature limit from any of the values in Table 1 and indicate whether the relevant instrument is designed for condensing or non-condensing humidity as well as the intended location for the relevant instrument, i.e. open or closed.

Table 1

	Temperature Limits
Upper temperature limit	30 °C	40 °C	55 °C	70 °C
Lower temperature limit	5 °C	–10 °C	–25 °C	–40 °C

(b) Mechanical environments—

(i) Mechanical environments are classified into classes M1 to M3 as described below—

• M1: This class applies to relevant instruments used in locations with vibration and shocks of low significance, for example, instruments fastened to light supporting structures subject to negligible vibrations and shocks transmitted from, for example, local blasting or pile-driving activities or slamming doors.

• M2: This class applies to relevant instruments used in locations with significant or high levels of vibration and shock, for example, transmitted from machines and passing vehicles in the vicinity, or adjacent to heavy machines or conveyor belts.

• M3: This class applies to relevant instruments used in locations where the level of vibration and shock is high and very high, for example, instruments mounted directly on machines or conveyor belts.

(ii) The following influence quantities shall be considered in relation with mechanical environments—

(aa) vibration;

(bb) mechanical shock.

(c) Electromagnetic environments—

(i) Electromagnetic environments, in relation to relevant instruments that are constructed using electrical components, are classified into classes E1 and E2 as described below.

• E1: This class applies to relevant instruments used in locations with electromagnetic disturbances corresponding to those likely to be found in residential, commercial and light industrial buildings.

• E2: This class applies to relevant instruments used in locations with electromagnetic disturbances corresponding to those likely to be found in other industrial buildings.

(ii) The following influence quantities shall be considered in relation with electromagnetic environments—

(aa) voltage interruptions;

(bb) short voltage reductions;

(cc) voltage transients on supply lines and/or signal lines;

(dd) electrostatic discharges;

(ee) radio frequency electromagnetic fields;

(ff) conducted radio frequency electromagnetic fields on supply lines and/or signal lines;

(gg) surges on supply lines and/or signal lines.

(2) Other influence quantities to be considered, where appropriate, are—

(a) voltage variation;

(b) mains frequency variation;

(c) power frequency magnetic fields;

(d) any other quantity likely to influence in a significant way the accuracy of the relevant instrument.

(3) When carrying out the tests as envisaged in these Regulations, the following paragraphs apply to relevant instruments in relation to ambient humidity—

(a) according to the climatic operating environment in which the relevant instrument is intended to be used either the damp heat-steady state (non-condensing) or damp heat cyclic (condensing) test may be appropriate;

(b) the damp heat cyclic test is appropriate where condensation is important. In conditions where non-condensing humidity is a factor the damp-heat steady state is appropriate.