IGEM - GM/7A
Electrical connections for gas metering equipment
|Publication Date:||1 March 2018|
This Standard covers electrical equipment and connections for gas metering equipment.
For the purposes of this Standard, "electrical equipment and connections" includes optical equipment and connections, unless otherwise stated.
This Standard applies to meter installations of maximum operating pressure (MOP) not exceeding 100 bar.
Additional requirements may need to be applied for installations having extensive communications systems, flow computers, etc.
This Standard applies to meter installations containing Natural Gas (NG) (a 2nd family gas as defined by BS EN 437) in a gaseous state.
Note: This Standard does not apply to either compressed or liquefied Natural Gas (CNG or LNG) vehicle filling station installations. Guidance on the latter is provided by IGEM/UP/20 and IGEM/UP/21 respectively or the Energy Institute (see A2.6).
Ambient temperatures are assumed to be in the range -25oC to 55oC.
This Standard applies to primary and secondary meter installations and associated volume conversion equipment in industrial, commercial and domestic premises, installed in accordance with IGE/GM/4 (see Note 4), IGEM/GM/5, IGEM/GM/6, IGEM/GM/8, BS 6400-1 or BS 6400-2, respectively and, where applicable, a hazardous area classification has been carried out in accordance with IGEM/GM/7B or IGEM/SR/25, as appropriate.
For an existing meter installation, this Standard applies only to new equipment being fitted for the first time or replacing existing electrical equipment i.e. it does not apply for existing equipment not being replaced.
Note 1: A meter installation in domestic premises is an installation within, or near to, a domestic dwelling into which the installation supplies gas and where it is reasonable to expect that the householder will be in the vicinity of the installation on a regular basis.
Note 2: A meter installation in industrial or commercial premises is an installation within the boundary of the industrial and commercial premises within which the gas load is located and where it is reasonable to expect that passers-by will be in the vicinity of the gas installation on a regular basis. This is to distinguish this type of installation from a remote site, for example a National Transmission System above-ground installation, where it is reasonable to expect that persons will not be present for long periods of time.
Note 3: Many of the principles of IGEM/GM/7A will apply to other gas meter installations having an unlimited installation pressure, for example at transmission boundary interfaces where gas measurement may take place. However, consideration would need to be given to the special circumstances affecting such installations, for example the remoteness of the site, high gas pressures and large gas volumes.
Note 4: For equipment installed in accordance with IGE/GM/4, an additional assessment will be required to ensure suitability.
This Standard considers:
• DSEAR and ATEX Directives
• pulse ownership
• equipment certification and suitability
• equipment connections
• details of electrical connections
• records and reporting.
Advice is provided on:
• legal requirements
• authorisation procedures
• electrical low frequency (LF) and high frequency (HF) outputs
• design of electronic interface equipment
• ensuring integrity of installation, operation and maintenance of a pulse chain
• procedures for telephone connections
• equipment location and installation
• equipment connection, protection and isolation
• inspection and maintenance.
This Standard applies to the connection of any electrical equipment to a gas meter, including:
• a volume conversion device
• AMR facilities
• add-on pulse modules
• a data logger
• an EMS
• radio transmitting devices
• a tamper circuit.
This Standard does not address any requirements relating to "gas work" under the Gas Safety (Installation and Use) Regulations (GS(I&U)R).
All pressures quoted are gauge pressures unless otherwise stated.
Italicised text is informative and does not represent formal requirements.
Appendices are informative and do not represent formal requirements unless specifically referenced in the main sections via the prescriptive terms "must", "shall" or "should".