Schneider 33662 MX Shunt Trip Release — Is This the Right Part?

By Abdullah Zahid
14 min read
Schneider 33662 MX Shunt Trip Release auxiliary solenoid coil for Compact NS and MasterPact circuit breakers

Schneider 33662 MX Shunt Trip Release — Specifications, Wiring, Compatibility & Where to Buy

When a plant engineer or maintenance team needs to add remote emergency shutdown capability to an existing Compact NS or MasterPact circuit breaker, the Schneider 33662 MX Shunt Trip Release is the direct-fit answer — no breaker replacement required. This auxiliary solenoid coil installs into the breaker's dedicated release cavity, accepts 200–250 V AC or DC control voltage, and mechanically trips the breaker latch within 50 ms of energization. If you are specifying a retrofit E-stop circuit, a fire alarm integration, or a UPS failover scheme on Compact NS 630b through NS3200 or MasterPact NT/NW hardware, this is the part that enables it.

If you have already confirmed this is the right part, check current pricing and availability for the Schneider 33662 at LeadTime.ca — we ship worldwide.

Who Should Buy the Schneider 33662 — and Who Shouldn't

The Schneider 33662 is the right choice for engineers and technicians adding remote trip functionality to an existing Compact NS or MasterPact installation. It belongs in your order if all of the following are true:

  • Your installed circuit breaker is a Compact NS (630b through NS3200), MasterPact NT, or MasterPact NW — confirmed from the breaker nameplate
  • Your site control circuit operates at 200–250 V AC or DC (verify from the one-line diagram, not from assumption)
  • The shunt trip coil cavity on the breaker frame is currently empty — only one MX or MN auxiliary release is permitted per breaker
  • A 50 ms response time from energize signal to mechanical trip is acceptable for your safety or emergency shutdown logic
  • Your application requires remote trip-only function, not a combined trip-and-close coil

If your control circuit operates at 400–415 V AC, if the installed breaker is from the PowerPacT M, P, or R series, or if you need a combined close-and-trip auxiliary, the Schneider 33662 is not the correct model. Contact the LeadTime.ca team to identify the right alternative before ordering.

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What the Schneider 33662 Actually Does in Your System

The Schneider 33662 is a voltage release coil — specifically, an MX shunt trip release — designed to be installed directly inside a compatible Compact NS or MasterPact circuit breaker chassis. It functions as an auxiliary solenoid: when the control circuit applies voltage to the coil terminals, the solenoid energizes, mechanically releases the trip latch inside the breaker, and forces the breaker open within 50 ms. The breaker does not need to be manually operated, and the release does not depend on an overcurrent condition to function.

This is the mechanism behind remote emergency stop circuits, fire panel breaker integration, and generator switchover automation. Without a shunt trip release installed, those control signals have no physical path to the breaker mechanism. The Schneider 33662 creates that path in a field-installable, IEC 60947-2 compliant package that weighs just 0.151 kg and fits within the existing breaker footprint — no enclosure modifications, no breaker replacement.

Two proof points support field confidence in this part. First, its 50 ms response time is fast enough to satisfy timing requirements in industrial emergency shutdown circuits aligned with safety standards such as ISO 13851. Second, its 4.5 VA holding power is low enough that existing low-capacity control transformers and battery-backed UPS systems can power the coil continuously without requiring capacity upgrades — a meaningful cost avoidance in retrofit projects. The coil trips when control voltage exceeds 70% of the rated value (threshold range: 0.7–1.1 Un), giving the control circuit a defined and reliable energize window.

Typical System Architecture for MX Shunt Trip Circuits

The Schneider 33662 sits between the control system output and the circuit breaker mechanical mechanism — it is the electromechanical translator that converts a control voltage signal into a physical trip event. Here is where it fits in a typical deployment:

  • Control power source (200–250 V AC or DC panel supply or UPS output) feeds the emergency stop chain or relay output
  • A normally-open contact — from an E-stop button, fire alarm relay, or PLC output — sits in series with the coil circuit
  • When that contact closes, control voltage energizes the Schneider 33662 coil terminals
  • The 33662 solenoid releases the mechanical trip latch inside the Compact NS or MasterPact breaker within 50 ms
  • The breaker opens, de-energizing the load circuit; the control circuit remains active until manually reset

Where the Schneider 33662 Gets Installed

The most common deployment is an emergency stop retrofit on an existing Compact NS or MasterPact installation. A manufacturing plant that originally installed breakers with manual-only trip capability later requires a hardwired E-stop circuit accessible from the control room or a remote panel — the Schneider 33662 adds that function without touching the power distribution equipment.

Fire safety integration is a frequent second application. When a building management system or dedicated fire panel must trip a specific feeder breaker upon alarm, the 33662 provides the solenoid-driven interface between the fire panel dry contact output and the breaker mechanism. The 50 ms response time and IEC 60947-2 compliance support approval by the authority having jurisdiction in most markets.

Data centers and facilities with generator backup commonly use the MX release for UPS failover or generator switchover logic — where the main feeder breaker must be tripped remotely before the alternate source is connected. Maintenance isolation is another use case: a technician in a safe location can initiate a trip without approaching the energized equipment, reducing arc flash exposure risk during controlled de-energization sequences.

Water treatment facilities, mining operations, and oil and gas installations use the Schneider 33662 in unattended site shutdown scenarios, where a remote monitoring system must de-energize equipment automatically when process or environmental limits are exceeded.

Application Typical Deployment
Emergency stop retrofit 33662 wired in series with E-stop pushbutton chain on existing Compact NS or MasterPact breaker
Fire alarm integration Fire panel dry contact closes, energizes 33662, trips feeder breaker on alarm signal
UPS/generator switchover Control relay output trips main feeder via 33662 before alternate source energizes
Maintenance isolation Technician initiates remote trip from safe distance using control room pushbutton wired to 33662
Unattended site shutdown Remote monitoring system output triggers 33662 to de-energize equipment on process alarm

Key Specifications and Compatibility Tables

Parameter Rating / Value Notes
Control Circuit Voltage 200–250 V AC or DC Specify AC or DC at time of order
Frequency 50/60 Hz Dual frequency compatible
Response Time 50 ms From energize signal to mechanical trip latch release
Supply Holding Power 4.5 VA Compatible with low-capacity control transformers and UPS
Threshold Tripping Voltage 0.7–1.1 Un Trips when control voltage exceeds 70% of rated value
Standard Compliance IEC 60947-2 Low-voltage switchgear auxiliary standard
RoHS Compliance Yes Compliant per EU directive
Dimensions (W × H × D) 6.0 cm × 3.3 cm × 8.2 cm Fixed mounting — no adjustable positioning
Weight 0.151 kg
Country of Origin France Standard import documentation; no atypical compliance issues reported

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

Compatible Circuit Breaker Platforms

Breaker Family Compatible Models Notes
Compact NS NS 630b to NS 3200 All frame sizes in range
MasterPact NT Full range No size restriction
MasterPact NW Full range No size restriction
PowerPacT (M/P/R) Not compatible Requires a different coil model — do not substitute
Merlin Gerin Legacy Not compatible Obsolete platform; requires separate sourcing review

If your breaker is a PowerPacT M, P, or R series, or a legacy Merlin Gerin frame, the Schneider 33662 will not fit — check the product page at LeadTime.ca or contact the team to identify the correct replacement model for your specific breaker.

Expert Verdict: Is the Schneider 33662 the Right Release for Your Breaker?

The Schneider 33662 MX Shunt Trip Release earns its place in retrofit and new-build specifications because it solves a real problem — adding remote or automatic trip capability to an already-installed Compact NS or MasterPact breaker — without requiring the breaker to be replaced. For electrical engineers specifying emergency stop circuits, panel builders standardizing on Schneider hardware across multi-site installations, and maintenance teams tasked with fire panel or UPS integration on existing distribution equipment, this is the logical and cost-effective choice. The 50 ms response time meets the timing requirements of standard industrial emergency shutdown circuits, the 4.5 VA holding power avoids control transformer capacity upgrades in retrofit scenarios, and the single model number covers Compact NS 630b through NS3200, MasterPact NT, and MasterPact NW — simplifying spare parts inventory for multi-site operators significantly.

The limits of the Schneider 33662 are well-defined and worth stating plainly. It is not the right part if your control circuit operates at 400–415 V AC — a different voltage variant is required for that architecture. It will not fit PowerPacT M, P, or R series breakers, which use a different coil interface entirely. If your application requires a combined trip-and-close auxiliary in a single unit, the 33662 does not provide that function. And because each Compact NS or MasterPact breaker accepts only one MX or MN auxiliary release, buyers need to verify the slot is empty before ordering — installing a second release into an occupied slot is not possible. These are not criticisms of the product; they are precisely bounded constraints that make it straightforward to qualify or eliminate the 33662 before committing to procurement.

From a sourcing perspective, the Schneider 33662 is a widely stocked auxiliary component with standard lead times — typically available within one to four weeks through authorized distributors, with expedited options possible. Buying through a specialist distributor rather than a surplus or grey-market channel matters here: the coil must be authentic, correctly voltage-rated, and traceable to a legitimate supply chain for installation confidence in safety-critical circuits. Check current availability and pricing for the Schneider 33662 at LeadTime.ca — we source from authorized channels and ship worldwide, with cross-reference verification support if you need to confirm compatibility before the order goes in.

For volume pricing, multi-site procurement, or to confirm lead time before committing your project schedule, contact the LeadTime.ca team directly — we ship worldwide and can expedite sourcing for emergency downtime situations.

What Engineers Need to Know Before Ordering the Schneider 33662

Because the Schneider 33662 is a specialized industrial auxiliary component — not a consumer product with broad forum visibility — buyers typically rely on manufacturer documentation, authorized distributor expertise, and integrator experience rather than public community threads. That sourcing pattern actually reflects the nature of the part: it installs inside safety-critical electrical infrastructure, and the consequences of ordering an incompatible variant are not just wasted money but a non-functional emergency shutdown circuit. The absence of online troubleshooting discussions is not a red flag; it reflects a buyer population that works through proper channels. What that means practically is that the specification and ordering decisions carry more weight than average, and getting them right the first time matters.

The most common ordering error with shunt trip releases in this class is voltage mismatch. A buyer pulls a replacement order from a previous PO without verifying whether the site control circuit is 200 V or 250 V, AC or DC — and the coil arrives, installs correctly physically, and then fails to energize at commissioning. The second most common error is breaker family confusion: Compact NS, MasterPact NT/NW, and PowerPacT are distinct platforms with different coil interfaces, and the nameplate on the breaker door is the only reliable source of truth. A third ordering trap is assuming the shunt trip slot is empty — if a previous technician already installed an MN undervoltage release, the slot is occupied and a second coil cannot be added without removing the first.

LeadTime.ca functions as the expert resource buyers consult when manufacturer documentation and distributor datasheets need a human cross-reference check. If you have the breaker nameplate photo, the control circuit voltage from your one-line diagram, and the existing auxiliary slot status confirmed, a quick conversation with the LeadTime.ca team can validate the Schneider 33662 is exactly what you need — or identify the correct alternative before the order is placed and a field visit is wasted.

Wiring and Installation Overview for the Schneider 33662

The following is a high-level installation overview for planning purposes. Engineers performing the actual installation must refer to the Schneider Electric breaker installation manual and applicable local electrical codes for complete procedures, torque specifications, and safety requirements.

  • De-energize and verify zero voltage on both the load circuit and control circuit before handling the breaker or installing the 33662 — a multimeter confirmation is required, not assumed
  • Inspect the breaker chassis for an empty MX/MN solenoid cavity; if an MN undervoltage release or another auxiliary already occupies the slot, the 33662 cannot be added without first removing the existing release
  • Insert the 33662 coil into the solenoid cavity, align the mounting tabs with the breaker frame slots, and secure with manufacturer fasteners — hand tools only, no power drivers; over-torquing the plastic frame is a documented installation failure mode
  • Wire the coil terminals in series with the emergency stop chain or remote trip contact, using a normally-open contact configuration; confirm control circuit fusing meets site standards and that return-to-neutral safety logic is in place
  • After wiring, verify coil resistance with a standard multimeter (do not use a megohm insulation tester on the active coil), then apply control voltage and confirm the solenoid energizes and the breaker trips within the 50 ms specification before returning the circuit to service

Wrong-Part Prevention Checklist Before Ordering the Schneider 33662

Use this checklist verbatim before submitting your purchase order. Every item must be confirmed — not assumed — before the Schneider 33662 is the right part to order:

  1. Verify circuit breaker series on nameplate — does it match Compact NS or MasterPact family?
  2. Confirm control circuit voltage — is it 200–250 V AC or DC at your site?
  3. Check if existing shunt trip slot is empty — one MX or MN release per breaker only
  4. Measure mounting surface on breaker to confirm fixed-mount position available
  5. Verify 50 ms response time is acceptable for your safety/emergency shutdown logic
  6. Confirm country of origin (FR/France) does not trigger import compliance issues in your region

If any item on this checklist cannot be confirmed, do not order before clarifying — contact the LeadTime.ca team with your breaker nameplate details and control circuit voltage, and we will identify the correct part before you commit the purchase order.

Frequently Asked Questions

Can I install the Schneider 33662 alongside an existing MN undervoltage release on the same breaker?

No. Compact NS and MasterPact breakers accept only one MX or MN auxiliary release per breaker — the solenoid cavity is a single-occupancy slot. If an MN release is already installed and you need to add an MX shunt trip function, the MN release must first be removed. Verify the slot status on your specific breaker before ordering.

What happens if the control circuit voltage is slightly below 200 V — will the 33662 still trip?

The threshold tripping voltage for the Schneider 33662 is 0.7–1.1 Un, meaning the coil is designed to initiate a trip when control voltage reaches at least 70% of the rated voltage. Below that threshold, the solenoid may not develop sufficient force to release the trip latch reliably. Always confirm your control circuit voltage under loaded conditions, not just at the transformer secondary, before specifying the coil voltage rating.

Is the Schneider 33662 a direct replacement for a failed shunt trip on an older Compact NS breaker?

If the installed breaker is a Compact NS 630b through NS3200 and the original release was an MX shunt trip rated for 200–250 V AC or DC, the Schneider 33662 is the correct replacement. Confirm the voltage rating on the old coil's nameplate matches the 200–250 V range and that the breaker series is within the compatible range. If the original coil was a different voltage (such as 110 V or 400 V), a different variant is required.

Can the Schneider 33662 coil be used on DC control circuits, or only AC?

The Schneider 33662 is rated for both AC and DC control circuits in the 200–250 V range, with AC frequency compatibility at 50/60 Hz. The AC or DC designation must be specified at the time of order, as different internal configurations may apply. Verify your site control circuit type from the one-line diagram and state it explicitly on the purchase order.

What is the consequence of using a megohm insulation tester on the 33662 coil after installation?

Do not use a megohm insulation tester (megger) on the 33662 coil. The test voltages used in standard insulation resistance testing can damage the coil winding. To verify coil integrity after installation, use a standard multimeter in resistance mode to check coil continuity. Functional commissioning testing should be performed by applying rated control voltage and confirming the breaker trips within the 50 ms specification.

Does the Schneider 33662 work with PowerPacT circuit breakers?

No. The Schneider 33662 is not compatible with the PowerPacT M, P, or R series breakers. Those platforms use a different coil interface and require a separate shunt trip model. Ordering the 33662 for a PowerPacT installation will result in a part that does not physically fit. Confirm your breaker series from the nameplate before ordering, and contact LeadTime.ca if you need to identify the correct PowerPacT-compatible release.

Why Order the Schneider 33662 From LeadTime.ca

  • LeadTime.ca sources Schneider Electric auxiliary components through authorized supply channels — critical for safety-rated parts installed in emergency shutdown and fire safety circuits
  • Cross-reference verification support available before you order — send your breaker nameplate details and control circuit voltage and the team will confirm compatibility
  • Ships worldwide — no geographic restriction on sourcing; useful for multi-site operators and international procurement teams
  • Volume pricing available for panel builders, contractors, and procurement teams ordering multiple units across a project or site standardization program
  • Rapid response for emergency replacement situations where downtime cost justifies expedited sourcing

Schneider 33662 At-a-Glance Summary

  • Product: Schneider 33662 MX Shunt Trip Release (Voltage Release MX), classified as a circuit breaker auxiliary accessory under IEC 60947-2
  • Control circuit voltage: 200–250 V AC or DC, 50/60 Hz dual frequency compatible
  • Response time: 50 ms from control voltage energize to mechanical trip latch release
  • Holding power: 4.5 VA — operable from low-capacity control transformers and battery-backed UPS without capacity upgrades
  • Threshold tripping voltage: 0.7–1.1 Un (trips at 70% of rated control voltage)
  • Physical dimensions: 6.0 cm (W) × 3.3 cm (H) × 8.2 cm (D); weight 0.151 kg; fixed mounting
  • Compatible breakers: Compact NS 630b through NS3200, MasterPact NT full range, MasterPact NW full range
  • Not compatible with: PowerPacT M/P/R series, Merlin Gerin legacy frames
  • One MX or MN release per breaker maximum — verify slot availability before ordering
  • Country of origin: France; RoHS compliant; IEC 60947-2 certified
  • Primary applications: emergency stop retrofit, fire alarm integration, UPS/generator switchover, remote maintenance isolation

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