BS EN 61000-3-12:2005 deals with the limitation of harmonic currents injected into the public supply system. The limits given in this International Standard are applicable to electrical and electronic equipment with a rated input current exceeding 16 A and up to and including 75 A per phase, intended to be connected to public low-voltage a.c. distribution systems of the following types:
- nominal voltage up to 240 V, single-phase, two or three wires
- nominal voltage up to 690 V, three-phase, three or four wires
- nominal frequency 50 Hz or 60 Hz.
Other distribution systems are excluded. The limits given in this edition apply to equipment when connected to 230/400 V, 50 Hz systems.
BS EN 61000-3-12:2005 applies to equipment intended to be connected to low-voltage systems interfacing with the public supply at the low-voltage level. It does not apply to equipment intended to be connected only to private low-voltage systems interfacing with the public supply only at the medium- or high-voltage level.
The scope of this standard is limited to equipment connected to public low voltage systems because emissions from equipment installed in private low voltage systems can be controlled in aggregate at the MV point of common coupling using procedures defined in IEC 61000-3-6 and/or by means of contractual agreements between the distribution network operator and the customer.
It is expected that operators of private systems will manage the EMC environment in a manner that ensures compliance with the provisions given in IEC 61000-3-6 and/or the contractual agreements.
If the equipment is intended to be connected only to private systems, the manufacturer should make this very clear in the product documentation.
Professional equipment with input current ≤ 16 A per phase and that does not comply with the requirements and limits of standard IEC 61000-3-2 may be permitted to be connected to certain types of low voltage supplies, in the same way as equipment with input current > 16 A per phase and that does not comply with the requirements and limits of the present standard IEC 61000-3-12.
The limits in this standard are not applicable to stand-alone harmonic filters. This standard defines:
- requirements and emission limits for equipment
- methods for type tests and simulations.
Tests according to this international standard are type tests of complete pieces of equipment.
