{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"RM4LG01B","brand":"Schneider Electric","brandSlug":"schneider","productSlug":"RM4LG01B","canonicalUrl":"https://aoctrl.com/schneider/RM4LG01B","factsUrl":"https://aoctrl.com/api/mcp/products/RM4LG01B","rawCanonicalId":null},"summary":{"shortDescription":"Schneider Electric Harmony RM4LG01B liquid level control relay, 22.5 mm width, 1 C/O output, sensitivity scale 5-100 kOhm, screw terminals, IP20 terminals / IP50 casing.","salesMarkdown":"## 22.5 mm DIN-rail fit for level sensing The RM4LG01B is a liquid level control relay from the Schneider Harmony RM4-L series, occupying 2.5 pitches of 9 mm on a DIN rail — that's a 22.5 mm footprint, so it slots into a standard panel without crowding adjacent control relays or terminal blocks. It detects liquid level through resistive probes, with a sensitivity scale adjustable from 5 to 100 kOhm, covering most conductive liquids from demineralised water to process chemicals. ## Output and switching specs for pump control A single changeover (1 C/O) contact with 90/10 silver-nickel alloy switches up to 250 V AC at 10 mA minimum, and the maximum switching voltage is 440 V AC. The 1.9 VA AC coil draw is light enough that a 24 V control transformer can drive several of these without derating. The electrode circuit is limited to 1 mA at 24 V AC — that's intentionally low to avoid electrolytic corrosion of the probe tips in conductive liquids. ## Lifecycle and compliance for BOM planning Pollution degree 3 per IEC 60664-1 and overvoltage category III mean it's rated for fixed industrial installations where transient overvoltages from the mains supply are expected — typical for a panel-mounted level relay.","metaTitle":"Schneider RM4LG01B Liquid Level Control Relay, 22.5 mm","metaDescription":"Schneider Electric RM4LG01B liquid level control relay, Harmony series, 1 C/O contact, sensitivity 5-100 kOhm, 22.5 mm wide, CE marked. Current lifecycle.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["General Purpose Relays"],"specifications":{"Width":"0.9 in (22.5 mm)","Marking":"CE : LVD 73/23/EEC CE : EMC 89/336/EEC","Category":"22376-RELAYS-MEASUREMENT(RM4)","Standards":"IEC 60255-6","Relay Type":"Liquid level control relay","Relay name":"RM4-L","Time Delay":"Without","9 Mm Pitches":"2.5","Output contacts":"1 C/O","lifecycle_stage":"current","Number of cables":"2","Pollution degree":"3 IEC 60664-1","Range of Product":"Harmony Relay","Contacts material":"90/10 silver nickel contacts","Power Consumption":"1.9 VA AC","Relative humidity":"15...85 % 3K3 IEC 60721-3-3","Sensitivity scale":"5...100 kOhm","Switching voltage":"250 V AC","Tightening torque":"5.3...9.7 lbf.in (0.6...1.1 N.m)","Operating position":"Any position without derating","Output relay state":"According to chosen function","Overvoltage category":"III conforming to IEC 60664-1","Mechanical durability":"30000000 cycles","Nbr. of units in pkg.":"1","Maximum cable capacity":"0 mF","Connections - terminals":"Screw terminals, 2 x 1.5 mm²flexible with cable end Screw terminals, 2 x 2.5 mm²flexible without cable end","Dielectric test voltage":"2.5 kV","IP degree of protection":"IP20 IEC 60529 terminals) IP50 IEC 60529 casing)","Switching capacity in mA":"10 mA 12 V","Maximum electrode current":"1 mA","Maximum electrode voltage":"24 V AC","Maximum switching voltage":"440 V AC","Product or Component Type":"Industrial measurement and control relays","Relay monitored parameters":"Detection by resistive probes","Supply disconnection value":"> 0.1 Uc","Operating Voltage Tolerance":"0.85...1.1 Uc","Contacts type and composition":"1 C/O","Electromagnetic compatibility":"Electrostatic discharge - test level: 6 kV level 3 (contact discharge) conforming to IEC 61000-4-2 Electrostatic discharge - test level: 8 kV level 3 (air discharge) conforming to IEC 61000-4-2","Resistance to fast transients":"2 kV IEC 61000-4-4 level 3","[Ui] rated insulation voltage":"500 V IEC","Disturbance radiated/conducted":"CISPR 22 - class A CISPR 11 group 1 - class A","Terminals description ISO n°1":"(15-16-18)OC (A1-A2)CO (B1-B2-B3)CO","[Ie] rated operational current":"2 A 158 °F (70 °C) 24 V DC-13 IEC 60947-5-1/1991 2 A 158 °F (70 °C) 24 V DC-13 VDE 0660 3 A 158 °F (70 °C) 115 V AC-15 IEC 60947-5-1/1991 3 A 158 °F (70 °C) 115 V AC-15 VDE 0660 3 A 158 °F (70 °C) 24 V AC-15 IEC 60947-5-1/1991 3 A 158 °F (70 °C) 24 V AC-15 VDE 0660 3 A 158 °F (70 °C) 250 V AC-15 IEC 60947-5-1/1991 3 A 158 °F (70 °C) 250 V AC-15 VDE 0660 0.1 A 158 °F (70 °C) 250 V DC-13 IEC 60947-5-1/1991 0.1 A 158 °F (70 °C) 250 V DC-13 VDE 0660 0.3 A 158 °F (70 °C) 115 V DC-13 IEC 60947-5-1/1991 0.3 A 158 °F (70 °C) 115 V DC-13 VDE 0660","Protection against electric shocks":"2 kV level 3 IEC 61000-4-5","Ambient Air Temperature for Storage":"-40...185 °F (-40...85 °C)","Resistance to electromagnetic fields":"9.1 V/m (10 V/m) IEC 61000-4-3 level 3","Ambient air temperature for operation":"-4...149 °F (-20...65 °C)","Resistance to electrostatic discharge":"6 kV contact IEC 61000-4-2 level 3 8 kV air IEC 61000-4-2 level 3","[Ith] conventional free air thermal current":"8 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$232.77","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://www.se.com/ie/en/product/RM4LG01B/liquid-level-control-relay-rm4l-24-v-ac/","alternativesUrl":"https://aoctrl.com/api/mcp/products/RM4LG01B/alternatives.json"},"ai":{"faq":[{"question":"What is the sensitivity range of RM4LG01B?","answer":"The sensitivity scale is 5 to 100 kOhm, adjustable to match the conductivity of the liquid being monitored — lower resistance for conductive process water, higher for demineralised or low-conductivity fluids."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/schneider/RM4LG01B","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/schneider/RM4LG01B when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}