K
Earth-fault current relay
Measuring relay form that operates on current flowing to earth, fed from a residual connection or core-balance CT.
Schematic / SLD
IEEE / ANSI · K
ANSI/IEEE Earth-fault current relay form
IEEE-library form of earth-fault current relay: measuring relay form that operates on current flowing to earth, fed from a residual connection or core-balance CT.
In plain English
What does ANSI/IEEE Earth-fault current relay form mean?
This reference locates earth-fault current relay in Autodesk's IEEE-oriented current protection relays family. The earth-fault current relay form identifies a relay whose operating quantity is current flowing to earth. It may be fed from a core-balance CT around all live conductors, from the residual connection of three phase CTs, or from a CT in the star-point earth lead, and the source changes its achievable sensitivity. The public library uses HCR1F37 for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number.
A simple example
Trace the measured quantity or initiating control signal separately from the output contacts. The device tag links the sensing or operating element to the controlled circuit; settings, reset behaviour and the actual terminal arrangement belong in the selected equipment documentation.
What the drawings help you do
The relay box shows the quantity with an earth additional drawing mark but not the setting, characteristic or whether it is directional. In resistance-earthed and isolated networks earth-fault current is small and often needs a sensitive or directional element that must be stated separately. Identify the CT arrangement that supplies the residual current. An earth-fault current relay measures current to earth; an earth-fault voltage relay measures neutral displacement voltage. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted.
This particular reference
IEEE-library form of earth-fault current relay: measuring relay form that operates on current flowing to earth, fed from a residual connection or core-balance CT. An earth-fault current relay measures current to earth; an earth-fault voltage relay measures neutral displacement voltage.
- Normally open / normally closed
- The contact state in the normal condition defined for the drawing.
- Coil
- A wound conductor that can produce a magnetic field when energised.
- Phase
- One of the related AC waveforms in a power system.
Read the source: Autodesk IEEE Symbol Preview: Current Protection Relays
IEEE / ANSI · Ground Failure Current Protection
Autodesk IEEE Symbol Preview: Current Protection Relays, block HCR1F37. Matching functional counterpart linked separately. Independently drawn educational geometry; not a certified IEEE glyph or database identifier.
Shown as an independently authored educational illustration. Use the cited publication and drawing legend to verify the required drafting form.
Schematic / SLD · K
What it represents
This reference locates earth-fault current relay in Autodesk's IEEE-oriented current protection relays family. The earth-fault current relay form identifies a relay whose operating quantity is current flowing to earth. It may be fed from a core-balance CT around all live conductors, from the residual connection of three phase CTs, or from a CT in the star-point earth lead, and the source changes its achievable sensitivity. The public library uses HCR1F37 for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number.
Trace the measured quantity or initiating control signal separately from the output contacts. The device tag links the sensing or operating element to the controlled circuit; settings, reset behaviour and the actual terminal arrangement belong in the selected equipment documentation.
The relay box shows the quantity with an earth qualifier but not the setting, characteristic or whether it is directional. In resistance-earthed and isolated networks earth-fault current is small and often needs a sensitive or directional element that must be stated separately. Identify the CT arrangement that supplies the residual current. An earth-fault current relay measures current to earth; an earth-fault voltage relay measures neutral displacement voltage. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted.
How to read it
- Identify the CT arrangement that supplies the residual current.
- Check whether the element is directional or sensitive.
Information to show or reference
- Show residual CT source
- State setting and characteristic
- Reference system earthing method
A distinction that matters
An earth-fault current relay measures current to earth; an earth-fault voltage relay measures neutral displacement voltage.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Autodesk IEEE Symbol Preview: Current Protection Relays
Public IEEE-oriented Current Protection Relays table explicitly lists HCR1F37 as Ground Failure Current Protection. This supports the vendor convention context, not reproduction of the publisher graphic.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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