Siemens - DT400NK Neutral Kit | 400A Non-Fusible Double Throw Safety Switch Solid Neutral Assembly

Siemens DT400NK Neutral Kit — a field-installable solid neutral assembly for 400A non-fusible double-throw safety switches. The DT400NK adds a grounded neutral conductor termination point to compatible Siemens double-throw safety switches, enabling their use in 4-wire systems where a switched neutral is required.

Why Choose the Siemens DT400NK?

Double-throw safety switches are used in applications where power must be transferred between two sources — utility power and a generator, for example. The DT400NK neutral kit is essential when the system uses a 4-wire (3-phase + neutral) configuration, as it provides a solid neutral bar to properly terminate and route the neutral conductor through the switch. Without a neutral kit, the neutral cannot be safely accommodated inside the enclosure.

Key Specifications

• Catalog Number: DT400NK
• Kit Type: Solid Neutral Assembly (Neutral Kit)
• Ampere Rating: 400A
• Voltage Rating: 240V / 480V / 600V AC; 25V DC
• Switch Type Compatibility: 400A Non-Fusible Double Throw (DT) Safety Switches
• Conductor Range: 6 AWG – 250 KCMIL (Copper or Aluminum)
• Number of Lugs: 7
• Dimensions: 3.188" × 3.434" × 8.5"
• Installation: Field installable
• Standards: UL Listed

What Is a Safety Switch Neutral Kit?

A neutral kit (also called a neutral assembly or neutral block) is an accessory that adds a grounded, isolated neutral bus bar inside a safety switch enclosure. It terminates the neutral conductor without switching it — keeping the neutral solidly connected while the phase conductors are opened or transferred by the switch. This is a code requirement in most 4-wire system applications under NEC Article 230 and 700.

Common Applications

• Generator transfer systems (utility-to-generator switching)
• 4-wire, 3-phase + neutral double-throw switch installations
• Service entrance applications requiring a solid neutral
• Emergency/standby power systems per NEC Article 700
• Field upgrade of existing 400A non-fusible DT safety switches

Installation Note

The DT400NK is designed for field installation into compatible 400A non-fusible double-throw safety switches. Always verify your switch's series and catalog number compatibility before purchasing. De-energize the switch completely before installation. Consult the NEC and local electrical codes for neutral handling requirements in transfer switch applications.