Siemens 3RV2901-1E Auxiliary Switch — Specs, Pricing & Selection

By Abdullah Zahid
13 min read
Siemens 3RV2901-1E SIRIUS transverse auxiliary switch module 1 NO 1 NC screw terminal for 3RV2 circuit breaker panel installation

Siemens 3RV2901-1E SIRIUS Auxiliary Switch, Transverse on the Front, 1 NO + 1 NC Screw Terminal for Circuit Breaker 3RV2 — Specs, Pricing and Selection Guide

If you are sourcing a transverse auxiliary contact module for an existing SIRIUS 3RV2 circuit breaker installation, the Siemens 3RV2901-1E is the specific plug-in unit that delivers one normally open and one normally closed instantaneous contact with screw terminal wiring — no crimp tools, no firmware, no replacement breaker required. Engineers working on motor control centers, SCADA-connected panels, and interlocked shutdown circuits specify this module when they need to extend the signaling capability of their 3RV2 breaker into a PLC discrete input or alarm relay without adding an external relay module and all the wiring that comes with it.

If you have already confirmed this is the correct part for your panel, check current pricing and availability for the 3RV2901-1E at LeadTime.ca — we ship worldwide.

Who Should Buy the 3RV2901-1E — and Who Should Not

This module is the right choice when all of the following conditions apply to your application:

  • Your existing circuit breaker is a Siemens 3RV2 in size S00, S0, S2, or S3 — no other breaker family is compatible
  • Your control logic requires exactly 1 NO contact and 1 NC contact — not 2 NO, 2 NC, or a changeover (CO) configuration
  • Your panel wiring uses screw terminals and copper conductors in the 0.5 to 2.5 mm² range (20 to 14 AWG)
  • Your control circuit voltage falls within the 24 V, 48 V, 60 V, or 230 V AC/DC range supported by the 3RV2901-1E ratings
  • Your panel has physical clearance for the transverse front-mount footprint: 45 mm wide, 12 mm high, 17 mm deep

If you need 2 NO or 2 NC contacts, require a side-mounted (lateral) auxiliary switch, or your breaker is not a 3RV2 S00 through S3 size, this is not the correct part — verify the alternative Siemens 3RV29xx lateral variant or a different contact configuration SKU before ordering.

On this page:

What the 3RV2901-1E Actually Does Inside a Control Panel

A 3RV2 circuit breaker on its own is a purely protective device — it trips on overload or short circuit and holds or breaks the power path. It tells you nothing about its current state unless you physically inspect the handle position. The Siemens 3RV2901-1E changes that. By plugging directly onto the front face of the breaker, it adds two instantaneous signal contacts — one NO and one NC — that mirror the mechanical state of the breaker in real time. When the breaker trips, the NO contact closes and the NC contact opens, and those state changes are immediately available to a PLC discrete input card, an alarm relay, a safety controller, or a hardwired interlock circuit.

The practical result is that a breaker sitting in a motor control center 50 meters from the control room can send its trip status directly to an HMI screen without a separate current transducer, without a relay module consuming panel space, and without any software configuration. The 3RV2901-1E is IP20 rated for finger-safe protection in vertical insertion, weighs 18 grams, and mounts in seconds by aligning to the plug-in receptacle on the front of the 3RV2 and pressing until it clicks flush. No screws, no brackets, no firmware to load.

The screw terminal connection supports solid or finely stranded copper wire from 0.5 to 2.5 mm² — covering the full range of typical control wiring without requiring ferrules or crimp tools, though core end sleeves are supported if your wiring practice requires them.

Typical System Architecture: Where the 3RV2901-1E Sits in the Signal Chain

The 3RV2901-1E sits between the mechanical switching layer of the 3RV2 breaker and the logic or monitoring layer above it, converting a physical breaker state into a routable control signal. A typical deployment chain looks like this:

  • PLC or safety controller — reads discrete input from auxiliary switch; executes alarm, interlock, or permissive logic
  • Control wiring (0.5 to 2.5 mm² copper, 20 to 14 AWG) — carries NO or NC contact state at 24 V or 230 V AC/DC to PLC input card or relay module
  • Siemens 3RV2901-1E auxiliary switch — plug-in module on front of breaker; 1 NO + 1 NC instantaneous contacts with screw terminals
  • Siemens 3RV2 circuit breaker (S00, S0, S2, or S3) — provides overcurrent and short-circuit protection for the downstream motor or load
  • Motor, pump, compressor, or other inductive load — protected by breaker; monitored via auxiliary switch contacts

Where Engineers Deploy the 3RV2901-1E: Industries and Use Cases

In food and beverage manufacturing, the 3RV2901-1E is commonly wired into pump and conveyor motor starter panels where a breaker trip must immediately signal a SCADA system or upstream PLC to halt a filling or packaging line before product contamination or mechanical damage occurs. The NO contact closes on trip and triggers a discrete input; the NC contact in its normal closed state can serve as a run-permissive signal that drops out the moment protection activates.

Water and wastewater treatment facilities rely on this module to send blower or pump breaker status back to a central SCADA panel. Critical pump stations often have no local operator, so the auxiliary switch is the only mechanism for detecting a tripped breaker before the station goes dry or overflows. The DC-13 rating at 24 V supporting 1.0 A makes the 3RV2901-1E well suited to 24 V DC control circuits common in these environments.

In pharmaceutical and biotech cleanroom HVAC panels, where IEC compliance and CE and CSA certifications are non-negotiable for regulatory sign-off, the 3RV2901-1E provides certified auxiliary contact functionality without introducing uncertified third-party modules into the panel. The CCC certification also makes it valid for installations in facilities with Chinese manufacturing operations.

Industrial machine builders and panel integrators use the 3RV2901-1E for hardwired motor interlocking — wiring NO contacts from one motor breaker into the coil control circuit of a second breaker to prevent simultaneous operation of forward and reverse drives. This approach eliminates a software dependency entirely: the interlock is physically enforced at the panel level regardless of PLC state.

Data centers and critical infrastructure operators fit the 3RV2901-1E to UPS distribution breakers and PDU feeder breakers where redundancy signaling to a power management controller requires a reliable, certified contact closure with no added latency from a relay coil.

Application Typical Deployment
Remote status monitoring (MCC) NO contact wired to PLC discrete input; trip status visible on SCADA HMI 50+ meters away
Motor interlocking (forward/reverse) NO contact from Breaker A wired into coil control of Breaker B; hardwired mutual exclusion
Alarm and SMS notification NO contact closes on compressor breaker trip; energizes 24 V alarm relay and SMS gateway module
Maintenance bypass logic NC contact wired to bypass relay held in override state by maintenance key switch
Safety redundancy confirmation Auxiliary contacts from two parallel breakers sampled by safety PLC before motor start permissive
HVAC / building automation Compressor breaker trip status delivered to BMS discrete input via 24 V DC control circuit

Electrical and Physical Specifications Worth Knowing Before You Order

Specification Value
Contact configuration 1 NO + 1 NC instantaneous contacts
AC-12 rating (resistive load) 2.5 A at 24 V and 230 V
AC-15 rating (inductive load) 2.0 A at 24 V / 0.5 A at 230 V
DC-13 rating 1.0 A at 24 V / 0.3 A at 48 V / 0.15 A at 60 V
Dimensions (W x H x D) 45 mm x 12 mm x 17 mm
Weight 18 g
Protection class IP20
Operating temperature -20°C to +60°C
Wire cross-section 0.5 to 2.5 mm² solid or stranded (20 to 14 AWG)
Certifications CE, UL, CSA, CCC; Railway Type Test Certificates available

Full technical specifications are available on the product page at LeadTime.ca.

3RV2901-1E vs Other Contact Configurations: Which One Does Your Circuit Actually Need?

Model Contact Configuration Mounting Orientation Terminal Type Best Fit
3RV2901-1E 1 NO + 1 NC Transverse (front) Screw Standard control and alarm circuits needing both a make and break contact on one module
Alternative 2 NO variant 2 NO Transverse (front) Screw Applications requiring two independent make contacts — confirm Siemens part number with distributor
Alternative 2 NC variant 2 NC Transverse (front) Screw Applications requiring two independent break contacts — confirm Siemens part number with distributor
3RV29xx lateral variant Varies Side-mounted (lateral) Screw Panels where front-face clearance is not available; different SKU and mounting interface

If your panel wiring and control logic confirm the need for 1 NO plus 1 NC on a screw terminal transverse front-mount module, the 3RV2901-1E is the correct Siemens part — check current stock and pricing at LeadTime.ca.

Expert Verdict: Honest Assessment for Controls Engineers and Procurement Teams

The Siemens 3RV2901-1E earns its place as the default auxiliary switch choice for 3RV2 breaker panels because it solves a specific, common problem — adding signaling to an existing mechanical breaker — with minimal parts, minimal wiring, and no additional commissioning work. The 1 NO + 1 NC configuration covers the most common control circuit scenarios in a single module: the NO contact handles alarm triggers and PLC inputs on trip, while the NC contact handles run-permissive and bypass logic during normal operation. CE, UL, CSA, and CCC certifications mean it clears compliance review in North American, European, and Chinese manufacturing environments without exception requests or additional documentation. The IP20 rating and instantaneous contact action are appropriate for the vast majority of industrial motor control applications where this module gets specified.

Where the 3RV2901-1E reaches its limits is at the current rating boundaries. At 230 V AC-15 — the inductive load rating that matters most when switching contactor coils — the contact rating is 0.5 A. That is adequate for standard coil circuits but leaves no margin if the control circuit is shared with other loads or if inductive kickback is not suppressed at the load. DC circuits are rated even lower: 0.15 A at 60 V DC-13. Engineers using the 3RV2901-1E in DC control circuits with voltages above 24 V should verify the exact current draw of their connected loads against those figures. If a single auxiliary switch is not sufficient — for example, if four or five separate control circuits each need to see the breaker state — a panel-mounted external relay offers more contacts at higher ratings, at the cost of more wiring and cabinet space. For single-signal applications, the 3RV2901-1E is almost always the more practical and cost-effective solution.

On the procurement side, the 3RV2901-1E is an active SIRIUS product with broad distributor coverage. Lead times from local stocking distributors typically run 2 to 7 days when in stock; ex-works from Siemens manufacturing runs 5 to 50 days depending on region and timing. For MCC retrofit projects ordering 10 or more units, volume pricing negotiations with your distributor are realistic and worthwhile. The EAN barcode 4011209790964 on the product packaging is the fastest way to confirm authenticity on receipt. If this matches your system requirements, view current stock and pricing for the 3RV2901-1E at LeadTime.ca.

For volume pricing or to confirm lead time before committing to a build schedule, contact the LeadTime.ca team directly — we ship worldwide.

Wiring and Installation Overview

  • De-energize the 3RV2 circuit breaker and confirm the handle is in the OFF position before mounting the 3RV2901-1E — align the module to the plug-in receptacle on the front face and press firmly until you feel a positive click and the switch sits flush with no visible gap
  • Identify the NO and NC terminal pairs on the module before inserting any wire — the NO terminal pair carries the contact that closes when the breaker trips; the NC terminal pair carries the contact that is closed during normal breaker operation and opens on trip
  • Insert solid or finely stranded copper wire (0.5 to 2.5 mm², 20 to 14 AWG) into the appropriate terminal; tighten screw terminals with a 0.5 to 1 mm flat-blade screwdriver and perform a firm pull test on each wire to confirm seating
  • For inductive loads connected to the NO or NC terminals at 230 V AC-15, verify the connected coil current does not exceed 0.5 A; for DC-13 circuits at 24 V, the maximum rated current is 1.0 A — do not exceed these values without adding external fusing or snubber protection on the load side
  • After wiring, manually trip the breaker using its test button, confirm the NO contact closes and the NC contact opens using a continuity tester or PLC input scan, then reset the breaker and verify contacts return to their initial states before energizing the control circuit

Wrong-Part Prevention: Confirm These Eight Points Before Submitting Your PO

A mis-ordered auxiliary switch creates panel downtime and re-stocking delays. Work through this checklist against your actual panel and breaker before placing your order:

  1. Confirm your 3RV2 circuit breaker size label (S00, S0, S2, or S3) matches product compatibility list
  2. Verify you need 1 NO contact + 1 NC contact, not 2 NO, 2 NC, or CO (changeover) contacts
  3. Check that your wiring uses screw terminals; plug-in connector types require different part numbers
  4. Confirm operating voltage is 24 V, 48 V, 60 V, or 230 V AC/DC range supported by 3RV2901-1E
  5. Ensure mounting space allows 45 mm width, 12 mm height, 17 mm depth transverse orientation
  6. Verify breaker was not damaged in a previous fault; test breaker operation before installing auxiliary switch
  7. Confirm your panel design allows conductor cross-sections of 0.5 to 2.5 mm² solid or stranded wire
  8. Check that 3RV29xx transverse mount fits; some custom or legacy panel designs may require retrofit brackets

If any item on this list raises a question, contact the LeadTime.ca team before ordering — we can help confirm compatibility with your specific breaker size and panel configuration.

Frequently Asked Questions

Is the 3RV2901-1E compatible with all 3RV2 circuit breaker sizes?

The 3RV2901-1E is compatible with 3RV2 circuit breakers in sizes S00, S0, S2, and S3. It is not designed for use with breaker sizes outside this range. Always check the size label printed on your specific breaker before ordering to confirm the match.

What is the difference between the AC-12 and AC-15 current ratings on this module?

AC-12 applies to resistive loads such as lamps and heating elements, and the 3RV2901-1E is rated 2.5 A at both 24 V and 230 V under this classification. AC-15 applies to inductive loads such as contactor coils and solenoid valves — the rating drops to 2.0 A at 24 V and 0.5 A at 230 V because inductive loads generate back-EMF spikes that stress contact surfaces more aggressively. Always confirm the load type and connected current before wiring the module into a 230 V coil circuit.

Can I use the 3RV2901-1E in a DC control circuit at 48 V or 60 V?

Yes, but the DC-13 current ratings are significantly lower than the AC ratings. At 48 V DC the rated current is 0.3 A, and at 60 V DC it drops to 0.15 A. Verify the exact current draw of your connected DC load against these figures before wiring, and consider adding a snubber or TVS clamp across any inductive DC load to protect the contacts from voltage spikes.

What happens if I need more than one NO or NC contact from a single breaker?

The 3RV2901-1E provides exactly one NO and one NC contact per module. If your application requires additional contacts — for example, feeding two separate PLC inputs or two separate alarm circuits — a panel-mounted external relay or an additional auxiliary switch in an available mounting position may be required. Confirm with a Siemens distributor whether stacking or additional modules are supported for your specific 3RV2 breaker configuration.

What certifications does the 3RV2901-1E carry for use in Canadian industrial panels?

The 3RV2901-1E carries CE, UL, CSA, and CCC certifications. The CSA mark specifically confirms compliance with Canadian electrical safety standards, making it a valid choice for panels subject to Canadian electrical inspection. Railway Type Test Certificates are also available if the module is being specified for rail industry applications.

How do I confirm I am receiving a genuine Siemens 3RV2901-1E and not a substitute part?

The EAN barcode 4011209790964 on the product packaging confirms authenticity. The catalog number on the product label should read 3RV2901-1E — verify this matches your purchase order line exactly, including the suffix. The MFN on the invoice may appear as 3RV29011E without the hyphen; both formats refer to the same product.

Why Source the 3RV2901-1E Through LeadTime.ca

  • LeadTime.ca ships worldwide — procurement teams across North America, Europe, Asia-Pacific, and beyond can place orders and receive accurate delivery estimates for their region
  • Access to hard-to-find SIRIUS accessories including the 3RV2901-1E when local electrical distributors show extended lead times or back-order status
  • Volume pricing available for multi-unit orders — MCC retrofits and OEM panel builds with 10 or more units benefit from negotiated rates
  • Technical product data verified against manufacturer sources — the specs on the LeadTime.ca product page reflect current Siemens datasheet information

At-a-Glance Summary

  • The Siemens 3RV2901-1E provides 1 NO + 1 NC instantaneous contacts in a 45 mm x 12 mm x 17 mm plug-in module for SIRIUS 3RV2 breakers
  • Compatible breaker sizes: S00, S0, S2, and S3 — verify size label on your breaker before ordering
  • AC-15 inductive rating: 2.0 A at 24 V, 0.5 A at 230 V — critical spec for contactor coil and solenoid valve circuits
  • DC-13 rating: 1.0 A at 24 V, 0.3 A at 48 V, 0.15 A at 60 V — verify DC load current before wiring
  • Screw terminal connection accepts 0.5 to 2.5 mm² (20 to 14 AWG) solid or stranded copper wire with or without core end sleeves
  • Operating temperature range: -20°C to +60°C; storage range: -50°C to +80°C
  • Protection class IP20; weight 18 g; transverse front-mount orientation only
  • Certified CE, UL, CSA, CCC; Railway Type Test Certificates available
  • EAN barcode 4011209790964 confirms product authenticity on receipt
  • Typical distributor lead time: 2 to 7 days in stock; 5 to 50 days ex-works; confirm before committing installation schedule