Littelfuse 777-KW/HP-P2 - The 777-KW/HP-P2 three-phase current and voltage monitor provides protection with input voltage from 200–480 V ac and motor full load ampere range as follows: 2–20 A (looped conductors required); 20–90 A direct; 90–800 A (external CTs required).
Littelfuse

777-KW/HP-P2

Alternate Item Number: 777-KW/HP-P2

UPC: 079458990997

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Overview

The Littelfuse 777-KW/HP-P2 is a three-phase current and voltage monitor designed for industrial motor protection in applications ranging from 200–480V AC and 2–800A. This versatile monitor integrates overload, undervoltage, phase loss/reversal, voltage/current unbalance, and underload trip protection into a single device. It supports multiple current measurement methods: looped conductors for 2–20A, direct connection for 20–90A, and external current transformers (CTs) for 90–800A, making it suitable for motors with non-linear load characteristics such as small, slow-speed, or lightly loaded motors. The 777-KW/HP-P2 features a built-in 3-digit LED display for real-time monitoring of voltage, current, kilowatts, horsepower, and fault diagnostics. It offers programmable voltage and current settings, three selectable restart options (automatic, semi-automatic, manual), and three programmable restart delay timers for rapid cycle protection, motor cool-down, and dry-well recovery. The device includes network communications capability via optional modules (Modbus, DeviceNet™, Profibus, Ethernet) for remote monitoring and control of up to 99 units from a PC, PLC, or SCADA system. Data logging is supported through Littelfuse Solutions software. Key specifications include a TC-overcurrent trip class of 5, 10, 15, 20, or 30 (with J prefix for jam protection), output contact rating of 10A @ 240V AC (general purpose) or 480VA @ 240V AC (pilot duty), and an operating temperature range of -40°C to 70°C. The monitor has a typical accuracy of ±3% for measured horsepower/kilowatts, ±1% for voltage, ±3% for current (<100A direct), and ±15% for ground-fault current. It meets IP20 and NEMA 1 protection standards and operates with 10W maximum input power. The 777-KW/HP-P2 is manufactured in the US and distributed by Gross Automation.
  • Monitors 200–480V AC voltage and 2–800A current (looped conductors, direct, or CTs)
  • Integrates overload, undervoltage, phase loss/reversal, and unbalance protection
  • Built-in 3-digit LED display for real-time voltage, current, kW, HP, and fault diagnostics
  • Network-ready with Modbus/DeviceNet/Profibus/Ethernet via optional modules (up to 99 units)
  • Programmable restart options and delay timers for motor protection and recovery

Specifications

Brand Name
Littelfuse
Connection Type
Looped conductors, direct, external CTs
Current Rating
2–800 A
Operating Temperature
-4 to 158
Operating Temperature, Maximum
158
Operating Temperature, Minimum
-4
Poles
3P
Series
777-KW/HP
Special Features
5YR WARR
Standard
UL/CE
Sub Brand
Symcom
Voltage Rating
200-480 V
Package Dimensions (L x W x H)
5.05 IN x 3.85 IN x 3.05 IN
Package Dimensions (L x W x H)
128.3 mm x 97.8 mm x 77.5 mm
The 777-P2 three-phase current and voltage monitor provides motor protection with input voltage from 200–480 V ac and motor full load ampere range as follows: 2–20 A (looped conductors required): 20–90 A (direct); 90–800 A (external CTs required).

777-P2

The 777-P2 three-phase current and voltage monitor provides motor protection with input voltage from 200–480 V ac and motor full load ampere range as follows: 2–20 A (looped conductors required): 20–90 A (direct); 90–800 A (external CTs required).
The 777-LR-P2 three-phase current and voltage monitor provides motor protection with input voltage from 200–480 V ac and motor full load ampere range of 1–9 A (direct); 10–800 A (external CTs required).

777-LR-P2

The 777-LR-P2 three-phase current and voltage monitor provides motor protection with input voltage from 200–480 V ac and motor full load ampere range of 1–9 A (direct); 10–800 A (external CTs required).
The 777-575-P2 three-phase current and voltage monitor provides motor protection with input voltage from 500–600 V ac and motor full load ampere range as follows: 2–20 A (looped conductors required); 20–90 A (direct); 90–800 A (external CTs required).

777-575-P2

The 777-575-P2 three-phase current and voltage monitor provides motor protection with input voltage from 500–600 V ac and motor full load ampere range as follows: 2–20 A (looped conductors required); 20–90 A (direct); 90–800 A (external CTs required).
The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.

460-MR

The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.
The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.

460-VBM

The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.
777-LR-KW/HP-P2 three-phase current and voltage monitor provides protection with input voltage from 200–480 V ac and motor full load ampere range as follows: 1–2 A (looped conductors required); 2.1–9.0 A direct; 10–800 A (external CTs required).

777-LR-KW/HP-P2

777-LR-KW/HP-P2 three-phase current and voltage monitor provides protection with input voltage from 200–480 V ac and motor full load ampere range as follows: 1–2 A (looped conductors required); 2.1–9.0 A direct; 10–800 A (external CTs required).
The 777-HVR-P2 three-phase current and voltage monitor provides motor protection with input voltage from 340–480 V ac and full load ampere range as follows: 2–20 A (looped conductors required); 20–90 A (direct); 90–800 A (external CTs required).

777-HVR-P2

The 777-HVR-P2 three-phase current and voltage monitor provides motor protection with input voltage from 340–480 V ac and full load ampere range as follows: 2–20 A (looped conductors required); 20–90 A (direct); 90–800 A (external CTs required).
The 201A is a 3-phase, auto-ranging, dual-range voltage monitor that protects 190-480VAC, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically selects between the 200V and 400V range. The 201A includes advanced single LED diagnostics, where color and different light patterns distinguish between faults and normal conditions.This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions. When a harmful condition is detected, the 201A’s output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to acceptable levels.

201A-9

The 201A is a 3-phase, auto-ranging, dual-range voltage monitor that protects 190-480VAC, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically selects between the 200V and 400V range. The 201A includes advanced single LED diagnostics, where color and different light patterns distinguish between faults and normal conditions.This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions. When a harmful condition is detected, the 201A’s output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to acceptable levels.
The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.

460-14

The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.
The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.

460-15

The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.
The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.

460-575

The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted.
3PH Lin-Lod VltMon/475-600V/aj.VUB,TD,RD. The 455 Series are 3-phase voltage monitors that combine load and line side monitoring to offer complete protection. Monitoring the load side will alert the user of contactor failure or impending contactor failure. Line side monitoring will also protect the motor from damaging fault conditions that may be present prior to the motor starting. With other line/load side monitors, the motor must be started before a voltage fault is detected. With the 455, your motor is fully protected at all times. The 455 Series are 3-phase, dual range voltage monitors that protect 190-480VAC, 50/60Hz motors, regardless of their size. It automatically selects between the 200V and 400V rangewhen the user selects the nominal voltage setpoint. Other adjustments include a 2-30 second trip delay, a 2-300 second restart delay (and manual restart) and a voltage unbalance trip point of 2-8percent. The voltage monitor’s circuitry is powered through the line side connections, so there is no need for separate control power, making it easy to install. Equipped with an infrared LED, the 455 Series can communicate to the optional hand-held diagnostic tool, Informer-MS to obtain valuable information such as real-time voltage, voltage unbalance on both line and load sides, motor run hours, last 20 faults, last 32 motor starts, high and low voltage trip points, voltage unbalance trip.

455-575

3PH Lin-Lod VltMon/475-600V/aj.VUB,TD,RD. The 455 Series are 3-phase voltage monitors that combine load and line side monitoring to offer complete protection. Monitoring the load side will alert the user of contactor failure or impending contactor failure. Line side monitoring will also protect the motor from damaging fault conditions that may be present prior to the motor starting. With other line/load side monitors, the motor must be started before a voltage fault is detected. With the 455, your motor is fully protected at all times. The 455 Series are 3-phase, dual range voltage monitors that protect 190-480VAC, 50/60Hz motors, regardless of their size. It automatically selects between the 200V and 400V rangewhen the user selects the nominal voltage setpoint. Other adjustments include a 2-30 second trip delay, a 2-300 second restart delay (and manual restart) and a voltage unbalance trip point of 2-8percent. The voltage monitor’s circuitry is powered through the line side connections, so there is no need for separate control power, making it easy to install. Equipped with an infrared LED, the 455 Series can communicate to the optional hand-held diagnostic tool, Informer-MS to obtain valuable information such as real-time voltage, voltage unbalance on both line and load sides, motor run hours, last 20 faults, last 32 motor starts, high and low voltage trip points, voltage unbalance trip.

Frequently Asked Questions about Littelfuse

What certifications and standards do Littelfuse products comply with?

Littelfuse products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Customers can verify specific product certifications by consulting individual product datasheets on Littelfuse.com, which provide comprehensive details about standards compliance for each component.

What industries and applications are Littelfuse products used for?

Littelfuse products are critical for electrical protection and safety across multiple industrial sectors, including manufacturing, automation, power distribution, and electrical control systems. Their comprehensive product portfolio serves industries that require robust electrical protection, including motor and pump applications, solar installations, programmable logic controllers (PLCs), electrical switch panels, and critical infrastructure environments. Key product lines protect against overcurrent, voltage transients, ground faults, and temperature-related electrical risks, ensuring equipment safety and operational reliability.

What technical support does Littelfuse offer?

Littelfuse offers comprehensive technical support through multiple channels. Their Technical Hotline (800-TEC-FUSE) provides direct access to engineers who can help identify issues and recommend solutions. Additionally, Littelfuse offers extensive online Technical Resources at Littelfuse.com, including datasheets, product manuals, whitepapers, application guides, and online design tools. Their experienced product and application engineers also provide step-by-step support from design to installation.

What are the main product lines offered by Littelfuse?

Littelfuse offers comprehensive industrial protection and control product lines, including fuses, fuse holders, protection relays, temperature sensors, and electrical safety components. Their key product categories span surge protective devices, custom OEM products, electrical switch panels, medium voltage fuses, ground-fault protection relays, motor and pump protection devices, and temperature sensors. These products are designed to minimize electrical safety hazards, limit equipment damage, improve productivity, and safeguard personnel from electrical faults.

What are the key features of Littelfuse products?

Littelfuse products feature exceptional circuit protection technologies with key characteristics including UL/IEC safety standard compliance, low internal resistance, and advanced protective capabilities across multiple product lines. Their components provide critical protection for industrial systems, offering features like overcurrent protection, voltage transient suppression, and resettable protection devices with ultra-low resistance and compact designs. Key product lines include fuses, metal oxide varistors (MOVs), TVS diodes, PolySwitch devices, and specialized electronic protection components that enhance system reliability and safety.

What environmental ratings do Littelfuse products have?

Littelfuse products feature comprehensive environmental ratings, including NEMA Type 1, 2, 3, 3R, 4/4X, 12, and 13 certifications, as well as IP65 protection. These ratings ensure superior protection in diverse industrial environments, with an operating temperature range of -40°F to +131°F (-40°C to +55°C). Many products also include UV-stabilized materials and neoprene gaskets for enhanced durability in outdoor and challenging conditions.

What accessories are available for Littelfuse products?

Littelfuse offers several key accessories across their product lines, including fuse holders, voltage monitoring modules, and terminal connectors. Specific accessories include the LPSM003ZXID (indicating) and LPSM003Z (non-indicating) POWR-SAFE Dead Front fuse holders for Class CC and Midget-Style fuses, the VRM6048 voltage monitor accessory module, and female quick connect terminals (P1015 series) in various wire gauge sizes. These accessories are designed to enhance protection, monitoring, and connectivity for Littelfuse electrical components.

What is Littelfuse's warranty policy?

Littelfuse provides comprehensive warranty details on their official website at www.littelfuse.com/warranty. Customers should visit this page to review the specific warranty terms and conditions for their specific product lines. For direct warranty support or questions, customers can contact Littelfuse Technical Support at 1-800-TEC-FUSE or email [email protected].

What communication protocols do Littelfuse products support?

Littelfuse supports a comprehensive range of industrial communication protocols, including PROFIBUS, PROFINET, EtherNet/IP, DeviceNet, Modbus RTU, and CANopen. Our products provide flexible connectivity solutions across multiple industrial automation platforms, enabling seamless integration with various control systems and network architectures.

How are Littelfuse products typically installed?

Littelfuse products are typically installed using specialized mounting hardware like fuse holders, blocks, and panels designed for specific industrial applications. The POWR-SAFE Dead Front holders, for example, provide optimum protection for Class CC and Midget-Style fuses, supporting installations up to 600 VAC/DC. Installation often involves using precision terminals with strain relief, such as 0.25 in. female quick connect terminals, to ensure secure and safe electrical connections in industrial control systems.