Schneider LS1D253A65 TeSys Fuse Disconnector Body (3P, 25A)

Product Overview

The LS1D253A65 is a robust 3-pole fuse-disconnector body from the Schneider Electric TeSys LS1 range. This high-reliability isolation device is specifically designed for the protection and manual disconnection of industrial electrical circuits. It accommodates 10 x 38 mm NFC fuses (AM or GG types) and features an integrated signaling circuit with 2 C/O early-break auxiliary contacts. These auxiliary contacts provide essential feedback to control systems or safety interlocking circuits before the main power poles open. Engineered for extreme environments, the LS1D253A65 operates in temperatures ranging from -50 to 70 deg C, making it an ideal choice for outdoor control panels, refrigeration systems, and heavy-duty industrial motor protection.

Technical Configuration

The LS1D253A65 is built for high-performance circuit isolation and safety signaling:

• 3-Pole Isolation: Provides simultaneous disconnection of all three phases in a compact 94 mm width footprint.

• Early-Break Contacts: Equipped with 2 C/O (Changeover) early-break auxiliary contacts. These contacts toggle before the main power circuit opens, allowing the control system to safely ramp down loads or trigger alarms.

• Fuse Compatibility: Designed for standard 10 x 38 mm NFC fuses, supporting both motor-rated (AM) and general-purpose (GG) fuse links.

• Mechanical Operation: Features a high-visibility toggle control for manual operation, with a mounting tolerance of +/- 23 degrees from the vertical position.

• High Voltage Rating: Rated for operational voltages up to 690 V AC for the power circuit and 500 V AC / 440 V DC for the signaling circuit.

Technical Specifications

Technical FAQs

What is the benefit of "Early-Break" auxiliary contacts in this device?Early-break contacts are a safety feature. They change state slightly before the main poles disconnect. This allows a PLC or safety relay to detect the disconnection intent and electronically shut down sensitive components (like variable speed drives or motor contactors) to prevent arcing across the main disconnector poles under load.

Can I use this disconnector for DC power circuits?The power circuit rating is specified for 690 V AC. While the signaling circuit is rated for 440 V DC, using the main poles for high-current DC disconnection requires specific de-rating and verification of the arc-extinguishing capabilities for DC. It is primarily intended for AC motor and distribution circuits.

Does this unit come with fuses included?No, the LS1D253A65 is a fuse-disconnector body. The 10 x 38 mm fuses must be selected and purchased separately based on the specific current and protection characteristics (AM or GG) required for your load.

Engineering & Installation Guide

• Mounting Orientation: The device is designed for vertical mounting on a standard 35 mm DIN rail. Ensure the mounting position stays within the +/- 23 degree tolerance to ensure the mechanical toggle operates correctly and the fuse carriers remain secure.

  
  

• Wiring the Signaling Circuit: Utilize the 2 C/O auxiliary contacts to interlock the disconnector with your upstream contactor. This ensures that the circuit is de-energized by a contactor capable of breaking the full load current before the manual disconnector is opened.

• Thermal Considerations: The "TH" protective treatment makes this device suitable for humid environments. However, in extreme cold (-50 deg C), ensure the toggle is operated slowly to prevent mechanical stress on the housing until the internal cabinet temperature stabilizes.

• Fuse Installation: Ensure fuses are fully seated in the carrier before closing the toggle. A loose fuse can cause localized heating and high resistance, leading to premature failure of the terminal base or the fuse itself.