BS 7856:2017
$167.15
Specification for special design and other features of alternating current watthour meters for active energy for use in the UK (Accuracy Classes A and B)
| Published By | Publication Date | Number of Pages |
| BSI | 2017 | 34 |
This British Standard specifies requirements for special design and other features of newly manufactured directly connected alternating current watthour meters with ratings up to and including 100 A I max for installation in domestic and small commercial/industrial premises.
This standard is principally aimed at the UK market, although it might also be of use to other markets. Within the UK the standard is aimed at manufacturers who intend to design and market meters, meter operators engaged in meter installation activities and those involved in meter procurement, such as energy suppliers and meter asset providers.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | Foreword |
| 7 | 1 Scope 2 Normative references 3 Terms and definitions |
| 8 | 4 Mechanical features |
| 9 | Table 1 — Dimensions and spacing of fixing holes and terminals |
| 10 | Figure 1 — Spacing of fixing holes and terminals for single-phase, two-wire meter |
| 11 | 5 Electrical features Table 2 — Standard currents for meters of Class A or Class B |
| 13 | Figure 2 — Diagrams of connections for a single-phase, two-wire, one-rate meter |
| 14 | Figure 3 — Diagrams of connections and graphical symbols for a two-element meter used on three-wire systems |
| 15 | Figure 4 — Diagrams of connections and graphical symbols for a two-element meter used on a two-phase, four-wire system |
| 16 | Figure 5 — Diagrams of connections and graphical symbols for a three-element meter used on a three-phase, four-wire system |
| 17 | 6 Other features |
| 18 | Annex A (normative) Test method of a terminal’s ability to safely clamp standard UK cables |
| 19 | Figure A.1 — Test arrangement for clamping ability of a meter terminal |
| 20 | Annex B (normative) External rate switching logic for multi-rate meters Table B.1 — Sequence for multi-rate registers having two to eight rates |
| 21 | Annex C (normative) Long-term overcurrent test requirements |
| 22 | Annex D (normative) Performance criteria for load switches inside meters Table D.1 — Performance criteria for supply control and load control switches |
| 23 | Figure D.1 — Polyphase meter supply control switch test timing |
| 24 | Figure D.2 — Contact resistance derived from mV drop measured at meter terminals at Imax |
| 25 | Annex E (normative) Sealing criteria |
| 26 | Annex F (informative) Operational considerations related to switches inside meters |
| 27 | Figure F.1 — Typical heating in a 100 AImax meter when subjected to 1.45 * Imax |
| 28 | Table F.1 — Thermal stresses on a 100 A SCS protected by various OCPD ratings |
| 29 | Table F.2 — Characteristics of OCPDs in common domestic use in the UK |
| 30 | Figure F.2 — Current levels for determining OCPD characteristics |
| 32 | Bibliography |
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