The mission of the OIML is to enable economies to put in place effective legal metrology infrastructures that are mutually compatible and internationally recognized, for all areas for which governments take responsibility, such as those which facilitate trade, establish mutual confidence and harmonize the level of consumer protection worldwide.

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Under-voltage / over-voltage

The meter detects condition when phase voltage rises above or drops below certain threshold levels. Such conditions are categorized as over-voltage or under-voltage. From samples of phase voltages the meter calculates the average values over a time period. This time period is synchronized with the meter clock. At the end of time period, each value of average phase voltage is compared to the over-limit and under-limit threshold parameters. When specific phase voltage value rises above over-limit threshold, an event for voltage over-limit is generated. Also when certain phase voltage drops below under-limit threshold, an event for voltage under-limit is recorded.

The meter also records end of voltage under/over limit condition (voltage normal event) when phase voltage returns between the two threshold levels. In order to prevent several events when phase voltage is exactly on the level of thresholds, a 2% hysteresis is implemented. This means that in order to detect normal voltage, phase voltage must rise additional 2% above parametrized under-limit threshold, or drop additional 2% below parametrized over-limit threshold.

 OBIS codes Any phase
Threshold for voltage over-limit12.35.0.1
Time threshold for voltage over-limit12.44.0.1
Threshold for voltage under-limit12.31.0.1
Time threshold for voltage under-limit12.43.0.1
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Personal Safety for electrical installations

It’s never a mistake to read the basics again.

  • Avoid contact with energized electrical circuits
  • Treat all electrical devices as if they are live or energized
  • Disconnect the power source before servicing or repairing electrical equipment
  • Use only tools and equipment with non-conducting handles when working on electrical devices
  • Never use metallic pencils or rulers, or wear rings or metal watchbands when working with electrical equipment
  • If it is necessary to handle equipment that is plugged in, be sure hands are dry and, when possible, wear nonconductive gloves, protective clothes and shoes with insulated soles
  • If it is safe to do so, work with only one hand, keeping the other hand at your side or in your pocket, away from all conductive material
  • Never touch another person’s equipment or electrical control devices unless you are instructed to do so
  • Enclose all electric contacts and conductors so that no one can accidentally come into contact with them
  • Never handle electrical equipment when hands, feet, or body are wet or when standing on a wet floor
  • When it is necessary to touch electrical equipment (for example, when checking for overheating), use the back of the hand. Thus, if accidental shock were to cause muscular contraction, you would not “freeze” to the conductor.
  • Be aware that interlocks on equipment disconnect the high voltage source when a cabinet door is open but power for control circuits may remain on.
  • De-energize open experimental circuits and equipment to be left unattended.
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