Digital Line monitoring relay with Neutral loss protection 3-phase 3-wire or 3-phase 4-wire 2 changeover 280-500 V AC (L-L) 160-300 V AC (L-N) 35 mm module - 7UG0814-1CA20

Product Description

Siemens 7UG0814-1CA20 Digital Line Monitoring Relay – Advanced 3-Phase System Protection with Neutral Loss Detection

Product Description

The Siemens 7UG0814-1CA20 is a SIRIUS digital line monitoring relay with neutral loss protection, designed for monitoring three-phase electrical networks in 3-phase 3-wire and 3-phase 4-wire configurations. It monitors critical power-supply conditions such as under-voltage, over-voltage, under-frequency, over-frequency, phase failure, phase sequence reversal, phase asymmetry and neutral loss.

The relay operates over a wide voltage range of 280–500 V AC line-to-line (L-L) and 160–300 V AC line-to-neutral (L-N). It has a built-in control supply, so a separate auxiliary supply is not required. The device provides 2 changeover outputs (1 CO + 1 CO) for alarm, control and protection circuits.

With its compact 35 mm module width and 35 mm DIN-rail mounting, the 7UG0814-1CA20 is well suited for industrial control panels, motor control centers, automation systems and electrical distribution applications where reliable three-phase line supervision and neutral-loss detection are required.

Key Features

• Brand: Siemens

• Product Family: SIRIUS 7UG

• Part Number: 7UG0814-1CA20

• Product Type: Digital Line Monitoring Relay

• Special Function: Neutral Loss Protection

• Network: 3-Phase 3-Wire / 3-Phase 4-Wire

• Supply Voltage: 240/415 V AC

• Operating Voltage L-L: 280–500 V AC

• Operating Voltage L-N: 160–300 V AC

• Control Supply: Built-in / Self-Powered

• Output Contacts: 2 CO

• Output Configuration: 1 CO + 1 CO

• Phase Failure Monitoring: Yes

• Phase Sequence Monitoring: Yes

• Phase Asymmetry Monitoring: Yes

• Neutral Loss Monitoring: Yes

• Under-Voltage Monitoring: Yes

• Over-Voltage Monitoring: Yes

• Under-Frequency Monitoring: Yes

• Over-Frequency Monitoring: Yes

• Frequency Range: 45–65 Hz

• Trip Delay: 0–999 seconds, programmable

• Operating Temperature: 0 to 50°C

• Relay Operation: Fail-Safe & Shunt Trip

• Rated Output: 5 A at 250 V AC, AC-12

• Module Width: 35 mm

• Mounting: 35 mm DIN Rail

• Standard: IEC 60947-5-1

Applications

The Siemens 7UG0814-1CA20 line monitoring relay is suitable for:

• Three-phase power supply monitoring

• Neutral loss monitoring

• Motor protection systems

• Motor control panels

• MCC panels

• Industrial automation

• Machine control cabinets

• Electrical distribution panels

• Pump control systems

• Compressor control panels

• HVAC systems

• Industrial machinery

• Generator systems

• Transformer secondary monitoring

• Factory automation

• Power supply supervision

• Electrical equipment protection

• Alarm and control systems

Benefits

• Digital three-phase line monitoring

• Dedicated neutral loss protection

• Supports 3-phase 3-wire systems

• Supports 3-phase 4-wire systems

• Wide 280–500 V AC L-L operating range

• 160–300 V AC L-N operating range

• Built-in control supply

• No separate auxiliary supply required

• Two changeover relay outputs

• Phase failure detection

• Phase sequence reversal detection

• Phase asymmetry monitoring

• Under-voltage protection

• Over-voltage protection

• Under-frequency monitoring

• Over-frequency monitoring

• Programmable trip time delay

• Fail-safe and shunt-trip operating modes

• Compact 35 mm DIN-rail module

• Suitable for industrial automation applications

Monitoring Functions

The 7UG0814-1CA20 continuously supervises the connected AC network and can identify several abnormal conditions:

• Under Voltage: Detects voltage falling below the configured threshold.

• Over Voltage: Detects excessive line voltage.

• Under Frequency: Monitors frequency below the configured limit.

• Over Frequency: Detects excessive frequency.

• Phase Asymmetry: Detects excessive voltage imbalance between phases.

• Phase Sequence: Detects incorrect phase rotation.

• Phase Missing: Detects loss of one or more phases.

• Neutral Loss: Detects loss of the neutral conductor in applicable 4-wire systems.

The trip time can be programmed from 0 to 999 seconds, allowing the relay to accommodate applications where short-duration voltage disturbances should not immediately initiate a protection response.

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Frequently Asked Questions

Q1. What is Siemens 7UG0814-1CA20?
The 7UG0814-1CA20 is a Siemens SIRIUS digital line monitoring relay with neutral loss protection for monitoring three-phase AC electrical networks.

Q2. Does 7UG0814-1CA20 provide neutral loss protection?
Yes. Neutral missing/loss is one of the dedicated monitoring functions of this model.

Q3. Which electrical systems are supported?
The relay supports 3-phase 3-wire and 3-phase 4-wire configurations. Siemens documentation also identifies the device for selectable network configurations within the 7UG0814 family.

Q4. What is the operating voltage range?
The operating band is 280–500 V AC L-L and 160–300 V AC L-N.

Q5. Does the relay require an external auxiliary supply?
No. The control voltage is built in, meaning the relay is powered from the monitored network.

Q6. How many relay outputs are available?
It provides 2 changeover outputs, configured as 1 CO + 1 CO.

Q7. What faults can the relay detect?
It can monitor under-voltage, over-voltage, under-frequency, over-frequency, phase asymmetry, phase sequence reversal, phase failure and neutral loss.

Q8. What is the frequency monitoring range?
The under-frequency and over-frequency monitoring functions operate across 45–65 Hz.

Q9. Is the trip delay adjustable?
Yes. The trip time delay is programmable from 0 to 999 seconds.

Q10. What is the module width?
The relay has a compact 35 mm module width and is designed for 35 mm DIN-rail mounting.

Q11. Where is 7UG0814-1CA20 used?
It is suitable for MCC panels, motor control panels, industrial automation systems, machine control cabinets, power distribution panels and three-phase electrical equipment.

Q12. Can it detect phase failure?
Yes. Phase missing/failure is one of the supported line-monitoring functions.

Q13. Can it detect incorrect phase sequence?
Yes. The relay monitors phase sequence reversal, helping identify an incorrect phase rotation condition.

Q14. Does it monitor voltage asymmetry?
Yes. Phase asymmetry monitoring is included, with the Siemens operating documentation specifying an adjustable range of 5–99.9%.

Q15. What type of output contacts does it have?
The relay has 1CO + 1CO, providing two independent changeover relay outputs for control, alarm or protection circuits.

Q16. Is the relay suitable for motor protection applications?
Yes. It can be integrated into motor control and protection circuits to supervise the incoming three-phase supply and initiate a control response when configured line faults occur.

Q17. What standard does the relay comply with?
The Siemens operating documentation identifies IEC 60947-5-1 for the device.

Q18. What is the difference between 7UG0818-1CA20 and 7UG0814-1CA20?
Both are three-phase line monitoring relays, but 7UG0814-1CA20 specifically adds neutral loss protection. Siemens' product comparison lists neutral-loss protection for 7UG0814-1CA20, while it is not listed for 7UG0818-1CA20.