# ANSI/IEEE Neutral-current measuring relay form Canonical URL: https://eloragrid.ai/symbols/ansi-neutral-current-relay Publisher: Elora Grid Updated: 2026-10-28 Lookup label: K Drawing use: Schematic, SLD Reference families: IEEE / ANSI, Manufacturer ## Symbol convention Convention: IEEE / ANSI Form: In Neutral Autodesk IEEE Symbol Preview: Current Protection Relays, block HCR1F32. Matching functional counterpart linked separately. Independently drawn educational geometry; not a certified IEEE glyph or database identifier. Related representation: [Neutral-current measuring relay](https://eloragrid.ai/symbols/neutral-current-relay) IEEE-library form of neutral-current measuring relay: measuring relay fed from a CT in a neutral conductor or star-point connection, responding to neutral current. ## In plain English ### What does ANSI/IEEE Neutral-current measuring relay form mean? This reference locates neutral-current measuring relay in Autodesk's IEEE-oriented current protection relays family. This relay form is used where a CT is installed in a neutral conductor or in the earthing connection of a transformer or generator star point. Current there indicates earth faults or, in four-wire systems, heavy unbalance and triplen harmonic loading, depending on where the CT sits. The public library uses HCR1F32 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 symbol identifies the measured conductor but not the purpose. A neutral CT in the star-point earth lead gives standby earth-fault protection, while one in the four-wire neutral of a feeder sees load unbalance as well, so settings and grading differ greatly. Confirm whether the CT is in the neutral conductor or the earthing lead. A neutral-current relay measures one neutral path; a residual connection sums the three phase CTs to derive the same quantity. 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 neutral-current measuring relay: measuring relay fed from a CT in a neutral conductor or star-point connection, responding to neutral current. A neutral-current relay measures one neutral path; a residual connection sums the three phase CTs to derive the same quantity. ### Terms - Winding: A coil of conductor inside an electrical machine or transformer. - 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. Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram. - [Autodesk IEEE Symbol Preview: Current Protection Relays](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-EC11EC4D-374C-4191-9534-C802D3932711.htm) - [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/) ## What it represents This reference locates neutral-current measuring relay in Autodesk's IEEE-oriented current protection relays family. This relay form is used where a CT is installed in a neutral conductor or in the earthing connection of a transformer or generator star point. Current there indicates earth faults or, in four-wire systems, heavy unbalance and triplen harmonic loading, depending on where the CT sits. The public library uses HCR1F32 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 symbol identifies the measured conductor but not the purpose. A neutral CT in the star-point earth lead gives standby earth-fault protection, while one in the four-wire neutral of a feeder sees load unbalance as well, so settings and grading differ greatly. Confirm whether the CT is in the neutral conductor or the earthing lead. A neutral-current relay measures one neutral path; a residual connection sums the three phase CTs to derive the same quantity. 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 - Confirm whether the CT is in the neutral conductor or the earthing lead. - Check grading against downstream earth-fault devices. ## Information to show or reference - Show neutral CT location - State setting and delay - Reference grading study ## Important distinction A neutral-current relay measures one neutral path; a residual connection sums the three phase CTs to derive the same quantity. ## Facts - Convention evidence: Autodesk IEEE Symbol Preview: Current Protection Relays; published form: In Neutral. - Public vendor block: HCR1F32. Vendor library token, not an IEEE symbol number. - Measured quantity: Current in a neutral or star-point conductor - Preview: Independent educational concept; consult the publisher and applicable standard for the exact graphic - Artwork scope: Original educational geometry. Exact standard graphics, product ratings and terminal pinouts are not certified. ## Public references - [Autodesk IEEE Symbol Preview: Current Protection Relays](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-EC11EC4D-374C-4191-9534-C802D3932711.htm) — Autodesk. Public IEEE-oriented Current Protection Relays table explicitly lists HCR1F32 as In Neutral. This supports the vendor convention context, not reproduction of the publisher graphic. - [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/) — IEC. IEC context for graphical symbols used in diagrams; no IEC graphic is reproduced. ## Graphic scope Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.