D165T LV Moulded Case Pole Mounted Breaker Digital Trip Unit

The D165T is a pole-mounted, molded-case circuit breaker engineered specifically for protecting distribution transformers on low-voltage overhead lines. This 4-pole breaker, rated at 165A and 440V, provides reliable protection against overloads, short-circuits, and phase imbalances. Housed in a weather-resistant fiberglass shell (IP31), it is built for outdoor operation from -25°C to 50°C. Featuring a digital trip unit, the D165T breaker can be precisely set to safeguard 50kVA, 100kVA, or 160kVA transformers. Its air-arc extinction technology ensures quick fault interruption, making this pole-mounted circuit breaker a robust and essential protection solution.

product details

Type Designation

LV Pole mounted circuit breakers

The protection and management of MV/LV transformers in rural areas requires the use of specific circuit breakers adapted tosignificant load imbalances, and thus guarantees complete power usage even in unbalanced conditions. These devices (4 poles, three of which are protected) use air-break technology with chambers with metal partitions to cut the arc. Low voltage pole mounted circuit breaker D165T with a digital trip unit.

Technical Parameters

	circuit breakers
	D165T	D265T
Reference strandard	NH63-S-11	NH63-S-11
Voltage rating Current rating	440V 165A	440V 265A
Cutout power Closing power	4000A 6800A	6400A 11700A
Number of poles Number of outputs	4 1 output	4 2 outputs
Cable sections	25/70mm*2	50/150mm*2
Breakdown voltage ·pulse/earth ·at 50Hz ·between poles	20KV 10KV 4KV	20KV 10KV 4KV
Control system	Manual	Manual
Installation	on post	on post

product Display

Working Ambient

Temperature: -40°C ~ +70°C
Humidity: 100%
Altitude: ≤2000m
Wind speed :≤40m/s • H

Note: No fire, no explosion hazards, no chemical c.rrosion and recurrent severe vibration.

Internal Structure Diagram

1. Incoming Wiring Clamp: Enables direct 4-phase power connection without crimping lugs.
2. Incoming Wiring Hole: Provides cable access for both incoming and outgoing connections.
3. Arc Chute Grid: User-replaceable component for effective arc extinguishing.
4. Operation Mechanism: Spring-charged closing mechanism operable via floor-mounted handle.
5. Digital Trip Unit: Configurable for 50/100/160 kVA with embedded current transformers.
6. Load Indicator Trip: Orange indicator drops to trigger trip when load time is reached.
7. Position Indicator: Green marker shows open/closed status through protrusion length.
8. Operation Handle: Controls tripping (downward) and closing (upward) operations.
9. Load Trip Enable/Disable Handle: Activates or deactivates the load trip function.