Schneider LADT2 Time Delay Contact Block — Specs & Compatibility

By Abdullah Zahid
15 min read
Schneider Electric LADT2 time delay auxiliary contact block for TeSys D and Deca contactors, front-mount screw clamp terminals

Schneider LADT2 Time Delay Auxiliary Contact Block: Specifications, Compatibility, and Selection Guide

If you are specifying or replacing a time delay auxiliary contact block for a TeSys D, TeSys F, or TeSys Deca contactor, the Schneider LADT2 is likely already on your shortlist. This front-mounting, screw-clamp block delivers one normally open and one normally closed contact with adjustable on-delay timing from 1 to 30 seconds, rated to 690V AC and certified across IEC, UL, CSA, VDE, and BS standards — a single SKU that travels across global supply chains without regional variant headaches. The question most engineers are actually asking at this stage is not what it is, but whether it fits their specific contactor model and timing requirement before they place the order.

If you have already confirmed this is the right part, check current pricing and availability at LeadTime.ca — ships worldwide.

Who Should Buy the LADT2 — and Who Shouldn't

The Schneider LADT2 is the right choice for engineers and technicians who are working within the TeSys D, TeSys F, or TeSys Deca contactor ecosystem and need a reliable, hardwired on-delay timing function. It is right for your application if all of the following are true:

  • Your contactor is from the TeSys D (CAD or LC1D), TeSys F (LC1F or CR1F), or TeSys Deca family — LADT2 mounts to these series; other contactor families use different accessory interfaces
  • Your timing requirement falls within the 1 to 30 second on-delay range — the block does not offer off-delay, pulse, or sub-1-second precision modes
  • Your system voltage does not exceed 690V AC (or 600V per UL/CSA for North American installations)
  • Your control circuit delivers at least 5mA at a minimum of 17V — signals below this threshold will not actuate the block
  • Your panel layout has front-face clearance for a 48mm x 44mm x 61mm block and your cable conductors fall within the 1 to 2.5mm range supported by screw clamp terminals

If your application requires off-delay timing, the LADT3 is the correct choice. For pulse-mode timing, specify the LADT4. If your contactor is not from the TeSys D, F, or Deca family, LADT2 will not mount correctly — consult your contactor manufacturer's accessory catalogue.

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What the Schneider LADT2 Actually Does in a Motor Control Circuit

The LADT2 is an electromechanical time delay auxiliary contact block that clips to the front face of a TeSys series contactor and adds on-delay timing logic to the control circuit — without requiring a separate timer relay, PLC output, or additional DIN rail component. When the contactor coil energizes, the LADT2 starts its internal timing cycle. After the set delay — anywhere between 1 and 30 seconds, adjusted via a manual potentiometer screw — the block transitions its 1NO and 1NC contacts. Until that delay expires, the auxiliary contacts remain in their rest state: the normally closed contact is closed, the normally open contact is open.

This is an on-delay function only. The contacts do not time out on de-energization. When the contactor drops out, the LADT2 auxiliary contacts return to rest immediately. Engineers who need the delay to occur on de-energization must specify the LADT3 instead. This distinction is the single most important functional point to confirm before ordering.

The block is rated for 5 million mechanical cycles — in a plant running the associated contactor 10 times per day, that represents a service life measured in decades under normal conditions. Combined with multi-standard certification across IEC 60947-5-1, UL 60947-5-1, CSA C22.2 No 60947-5-1, VDE 0660, BS 4794, and NF C 63-140, the LADT2 qualifies for use across virtually every major industrial region from a single SKU, reducing the inventory complexity that plagues multinational operations.

Where the LADT2 Sits in Your Control System

The LADT2 is an accessory that extends the TeSys contactor's signal-processing capability — it sits between the energized contactor and the downstream control logic that needs a delayed confirmation signal.

  • Upstream: PLC output, control transformer secondary, or hardwired 24VDC/120VAC control circuit energizes the TeSys contactor coil
  • Contactor: TeSys D, F, or Deca main contacts close; coil signal also triggers LADT2 internal timing cycle simultaneously
  • LADT2 block: After the set delay (1-30 seconds), the 1NO contact closes and the 1NC contact opens — providing a delayed confirmation or interlock signal to the next stage in the circuit
  • Downstream: Secondary motor starter, valve solenoid, alarm relay, or PLC digital input receives the delayed signal to initiate the next step in the control sequence
  • Protection: Upstream GG 10A fuse recommended for the LADT2 signal circuit; main power protection handled separately at the contactor level

Typical Applications and Deployment Scenarios

In multi-stage conveyor systems, the LADT2 prevents simultaneous full-load inrush by introducing a controlled delay between successive motor starts. Rather than energizing three conveyor drives simultaneously, the sequence controller starts the first motor, waits for the LADT2's 5 to 10 second delay to expire, then receives the NO contact closure as permission to energize the next stage. The result is a staged current draw that protects both the power supply and the mechanical drive components.

Process control applications — particularly pumping stations and water treatment facilities — use the LADT2 for time-dependent interlock logic. A common scenario: a pump contactor energizes, the LADT2 begins its timing cycle, and only after the delay (typically 3 to 7 seconds) does the auxiliary NO contact close to permit a downstream valve solenoid to open. This prevents valve actuation before the pump has reached operating pressure, avoiding water hammer and valve damage.

In HVAC and building services applications, the block serves as an alarm or status signal delay. Transient overloads during motor startup can trigger nuisance fault signals; the LADT2 introduces a supervised delay before the status signal is passed to the BMS, filtering false shutdowns without requiring software logic changes.

Food and beverage packaging machinery, wastewater treatment blowers, mining conveyors, and steel mill auxiliary drives all present applications where the 1 to 30 second on-delay range covers the majority of real-world sequencing requirements. The 5-million-cycle mechanical durability rating is particularly relevant in high-cycling packaging lines where contactors may actuate dozens of times per hour.

Application Typical Deployment
Multi-stage conveyor sequencing LADT2 delays second motor start 5-10 seconds after first stage energizes, preventing simultaneous inrush
Pump and valve interlock 3-7 second on-delay before valve solenoid receives permission signal, confirming pump at operating pressure
HVAC fan and cooling system startup Motor runs, 3-second LADT2 delay, then cooling fan auxiliary circuit activates once primary motor is at speed
Transient alarm filtering LADT2 delays BMS or SCADA status signal 2-5 seconds to prevent nuisance trips during motor startup transients
Motor soft-start protective delay After soft-start ramp-down completes, LADT2 holds fault signal circuit open for programmed period before signaling downstream protection
Mining and cement conveyor interlock Sequential drive startup with 10-15 second delays between stages; LADT2 NC contact used as permissive interlock in each stage

Purchase-Decision Specifications and Variant Comparison

Parameter Value
Contact Configuration 1NO + 1NC
Rated Operational Voltage (Ue) 690V AC at 25-400Hz (IEC); 600V (UL/CSA)
Rated Operational Current (Ie) 6A at 120V AC
Minimum Switching Current 5mA
Minimum Switching Voltage 17V
Timer Type / Range On-delay only, 1 to 30 seconds adjustable
Adjustment Method Manual potentiometer screw (small flat-blade screwdriver)
Mechanical Durability 5 million cycles
Physical Dimensions (H x W x D) 48mm x 44mm x 61mm
Terminal Type / Conductor Range Screw clamp, 1 to 2.5mm flexible or rigid

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

LADT2 vs. LADT3 vs. LADT4: Which Timer Block Do You Need?

Model Timer Function Contact Configuration Delay Range Right For
LADT2 On-delay 1NO + 1NC 1 to 30 seconds Delay occurs after contactor energizes; most common motor sequencing and interlock requirement
LADT3 Off-delay 1NO + 1NC Varies — verify datasheet Delay occurs after contactor de-energizes; required for run-on logic, braking interlocks, or post-stop delays
LADT4 Pulse mode 1NO + 1NC Varies — verify datasheet Contact closes for a defined pulse duration after energization; used in one-shot signal applications

If your control logic requires the delay to begin when the contactor drops out rather than when it picks up, the LADT3 is the correct choice — visit the LeadTime.ca product page to confirm variant availability and current lead times.

Expert Verdict: Is the LADT2 the Right Block for Your Project?

For integration firms and plant maintenance teams running TeSys D or TeSys Deca contactor systems, the LADT2 is the lowest-risk, fastest-to-commission solution for on-delay timing logic. Its 5-million-cycle mechanical durability rating means that even in high-cycling packaging or conveyor applications, this block is unlikely to become a maintenance item within the operational life of the panel it is mounted in. The multi-standard certification across IEC, UL, CSA, VDE, BS, and NF standards means OEM panel builders serving international customers can specify a single SKU without managing country-specific variants — a real inventory and documentation advantage for facilities with global supply chains. The 1 to 30 second adjustable range covers the vast majority of industrial motor control sequencing and interlock scenarios, and the front-clip mounting eliminates the need for additional DIN rail space or remote timer wiring.

The LADT2 has real constraints that matter at the specification stage. It is strictly an on-delay device — if your application needs a delay after the contactor drops out, you need the LADT3. If you need pulse-mode timing, specify the LADT4. Sub-1-second precision is not achievable with the LADT2, and applications at voltages above 690V AC are outside its ratings. For new control panel designs where complex or variable timing logic is required, a compact PLC or programmable relay often delivers more flexibility at lower total cost than a collection of hardwired timer blocks. In retrofit scenarios or standardized motor control centres where TeSys contactors are already installed and the timing requirement is straightforward, the LADT2 remains the fastest, most documentation-friendly path to commissioning.

From a procurement standpoint, the LADT2 benefits from Schneider Electric's global distribution network, but actual stock availability and lead time vary significantly by region and distributor. North American buyers in particular should verify current inventory before committing to a project schedule — typical lead times of 1 to 3 weeks are common but not guaranteed, and Canadian procurement can involve additional logistics considerations compared to US-stocked distribution. Buying through a specialist automation distributor rather than a generic online channel gives you access to pre-order compatibility verification and application support, which reduces the risk of a non-fitting block arriving on site. Check current availability and pricing for the LADT2 at LeadTime.ca — we ship worldwide and can confirm lead time before you commit to a build schedule.

For volume pricing on multi-unit panel builds or to confirm lead time before finalizing your bill of materials, contact the LeadTime.ca team directly — we ship worldwide and work with procurement teams across every time zone.

What Integrators and Technicians Need to Know Before Ordering the LADT2

Unlike many industrial automation components, the LADT2 generates virtually no public forum discussion — a search across Reddit's automation and PLC communities, PLCTalk, PLCS.net, MrPLC, Schneider's own support forums, and major distributor Q&A sections returns no results for this model or the broader TeSys auxiliary timer category. This is not unusual for mature, specialist contactor accessories. Engineers who work with these products regularly resolve questions through direct Schneider technical support, distributor application teams, or in-house commissioning procedures — not public troubleshooting threads. The absence of forum data reflects a product category that works reliably when correctly specified, not one that is obscure or poorly supported.

What the technical documentation does reveal — and what integrators consistently encounter — is that the most common source of project delay with any TeSys auxiliary block is contactor size mismatch at the point of order, not product failure in service. The LADT2 mounts to TeSys D (all CAD and LC1D sizes), TeSys F (LC1F and CR1F only), and TeSys Deca. It does not mount to all Schneider contactors universally, and older TeSys R variants require separate verification. Writing down the exact model number from the contactor's manufacturer plate — including the series and size code — before placing the order is the one action that prevents the majority of wrong-part returns in this product category.

A second documented specification point that causes site surprises: the LADT2 requires a minimum switching current of 5mA and a minimum switching voltage of 17V at its control terminals. Low-current passive sensor outputs and some PLC digital outputs operating at 12V will not reliably actuate the block. This needs to be verified at the control circuit design stage, not during commissioning. If your signal source cannot meet these minimums, inserting a relay or signal amplifier upstream is the correct solution. When community data is sparse and manufacturer documentation contains these kinds of threshold conditions, specialist distributor support becomes the practical alternative to forum research — a team familiar with the LADT2 can confirm these requirements against your specific control circuit before shipment.

Wiring and Installation Overview

The following points cover the key requirements for LADT2 mounting and wiring. For complete installation procedures, refer to Schneider Electric's official installation instruction document supplied with the product or available on se.com.

  • De-energize the entire control circuit and lock out the disconnection point before handling the contactor or LADT2; verify with a meter that no voltage is present at any terminal before proceeding
  • Align the LADT2 clip mechanism with the front-mounting tabs on the TeSys contactor body and apply steady forward pressure until the block snaps positively into place with no wobble or gap — the block should sit flush with the contactor face
  • Strip 5 to 8mm of insulation from each control wire; for stranded conductors, use a ferrule (supporting 1 to 2.5mm flexible or rigid conductors) before inserting into screw clamp terminals
  • Tighten each screw terminal to exactly 1.7N.m using a 6mm flat-blade or Philips No. 2 screwdriver — over-tightening damages the terminal block; confirm wire retention by gently pulling each conductor after tightening
  • After restoring power, verify control signal current is at least 5mA at a minimum of 17V before beginning time delay calibration; adjust the potentiometer screw in small increments, testing delay duration after each adjustment, until the timing matches your application requirement

Compatible TeSys Contactor Series

The LADT2 is compatible with the following TeSys contactor families. Verify your exact contactor model number against this matrix before ordering — mounting interface differences between series and older variants can result in non-fitting accessories.

Contactor Series CAD Size LC1D Size LC1F / CR1F Size TeSys Deca
TeSys D Yes Yes Yes N/A
TeSys F No No Yes (LC1F and CR1F only) N/A
TeSys Deca Yes Yes N/A Yes
Older TeSys R Verify Limited Limited N/A

Wrong-Part Prevention Checklist

Before finalizing your order for the LADT2, work through each of the following checks. This checklist is drawn directly from documented specification constraints and the most common sources of wrong-part orders in this product category.

  1. Verify exact TeSys contactor model number you are mounting to (LADT2 mounts front; CAD size, LC1D size, or LC1F size compatibility must match)
  2. Confirm on-delay is the timing function needed, not off-delay or pulse
  3. Check that system voltage does not exceed 690V AC (standard rating); if higher, different block required
  4. Verify screw clamp terminals match your cable sizes (1-2.5mm flexible or rigid supported)
  5. Confirm clip-on front mounting clearance available (height 48mm, width 44mm, depth 61mm); no top-mounted accessories will interfere
  6. Check that 1NO+1NC contact arrangement matches your control logic (e.g., not a model needing 2NO or 2NC only)
  7. Confirm GG 10A fuse protection is acceptable for your signal circuit (higher fault currents need external protection)

If any item on this checklist is unresolved before ordering, contact the LeadTime.ca team — our application team can verify compatibility against your specific contactor model and control circuit requirements before shipment.

Frequently Asked Questions

Is the LADT2 compatible with older TeSys contactor models, and how do I confirm fit before ordering?

The LADT2 is confirmed compatible with TeSys D (all CAD and LC1D sizes), TeSys F (LC1F and CR1F only), and TeSys Deca. Older TeSys R models and non-standard configurations require individual verification — the safest approach is to read the exact series and size code from the manufacturer plate on your installed contactor and cross-reference against Schneider's official compatibility documentation or contact your distributor before ordering. A dry-fit test (aligning the LADT2 clip on a de-energized contactor before wiring) is the most reliable on-site check.

What happens if my control signal is below the 5mA minimum switching current?

If the signal delivered to the LADT2 terminals is below 5mA or below 17V, the block will not respond — the timing cycle will not initiate and the auxiliary contacts will remain in their rest state regardless of contactor energization. This is a documented minimum threshold, not a soft guideline. If your signal source is a low-current passive sensor or a 12V PLC digital output, insert an interposing relay or signal amplifier upstream to bring the signal within the required operating envelope before it reaches the LADT2 terminals.

Can the time delay be adjusted after installation, or does it require removal of the block?

The time delay is adjusted via a manual potentiometer screw accessible on the face of the LADT2 block while it is mounted on the contactor. A small flat-blade screwdriver is used to turn the screw in incremental steps — counterclockwise toward the 1-second minimum, clockwise toward the 30-second maximum. Adjustment can be performed in the field without removing the block, but the circuit should be de-energized during adjustment and re-tested at operating conditions after each change to verify the new timing setting.

If I need a delay that starts when the contactor turns off, is LADT2 still the right part?

No. The LADT2 is an on-delay block only — the timing cycle begins when the contactor energizes, and the auxiliary contacts return to rest immediately when the contactor drops out. If your application requires the delay to begin after de-energization (for example, a run-on signal that holds a downstream circuit active for a period after the motor stops), the LADT3 is the correct variant to specify. Ordering LADT2 for an off-delay application will result in timing logic that does not behave as intended.

Does the LADT2 require any periodic maintenance, or is it a sealed replacement unit?

Schneider Electric's official documentation does not specify a field maintenance procedure for the LADT2 — no contact cleaning interval or potentiometer service guidance is published. The 5-million-cycle mechanical durability rating is the primary design life indicator. In practice, these blocks are treated as sealed units: when a timing or contact fault is identified, the standard approach is block replacement rather than field repair. Keeping one spare unit on the shelf is advisable for critical motor control applications where downtime cost is significant.

Can the LADT2 be used in applications where a PLC is also controlling the circuit?

The LADT2 is a hardwired electromechanical device — it responds to the physical energization of the contactor coil and produces a delayed dry-contact output. It does not communicate digitally with a PLC. In hybrid systems where a PLC manages the contactor, the LADT2's auxiliary contacts can feed back to a PLC digital input as a delayed confirmation signal, or they can directly actuate a downstream element in the hardwired circuit. What the LADT2 does not do is accept a digital timing command from the PLC — if the PLC needs to vary the delay time dynamically, the timing function must be implemented in PLC software with a standard (non-timed) auxiliary contact block used for signal feedback.

Why Order the LADT2 Through LeadTime.ca

  • LeadTime.ca ships worldwide — whether your project is in Canada, the US, or international, we source and dispatch to your location
  • Specialist automation distributor with application familiarity in TeSys contactor accessories — not a general online marketplace
  • Volume pricing available for panel builders and OEMs ordering multiple units — contact us for a consolidated quote
  • Current stock status and lead time confirmed before you commit to a build schedule, reducing project risk from supply surprises
  • Direct support channel for compatibility verification — if your contactor model is on the edge of the compatibility matrix, ask before ordering

At-a-Glance Summary

  • Contact configuration: 1NO + 1NC with on-delay timing only — LADT3 required for off-delay, LADT4 for pulse mode
  • Adjustable delay range: 1 to 30 seconds via manual potentiometer screw; covers the majority of industrial motor sequencing requirements
  • Voltage rating: 690V AC (IEC); 600V (UL/CSA for North American installations)
  • Minimum switching thresholds: 5mA current and 17V voltage at control terminals — verify signal source before specifying
  • Mechanical durability: 5 million cycles rated
  • Physical footprint: 48mm height x 44mm width x 61mm depth; front clip-on mounting to TeSys contactor face
  • Terminal type: Screw clamp, supporting 1 to 2.5mm flexible or rigid conductors; tightening torque 1.7N.m
  • Certifications: IEC 60947-5-1, UL 60947-5-1, CSA C22.2 No 60947-5-1, VDE 0660, BS 4794, NF C 63-140 — single SKU for global deployment
  • Compatible with: TeSys D (all CAD and LC1D sizes), TeSys F (LC1F and CR1F only), TeSys Deca — older TeSys R requires individual verification
  • Upstream protection: GG 10A fuse recommended for the LADT2 signal circuit

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