An experienced technician was performing annual maintenance on a large electrical installation. In accordance with internal safety procedures, she began by applying the Lockout-Tagout-Tryout (LOTO) procedure. After identifying the correct control cabinet, she switched off the main power supply, locked the main switch with a personal padlock, and attached a tag with her name and date.
She then performed the verification step: checking whether the installation was actually de-energized. A REMLIVE RL-24i Isolator Check was mounted on the cabinet door. The front display was clearly flashing, indicating the presence of voltage. Despite switching off the main switch, an energy source was still active.
Further investigation revealed that an additional supply branch had not been isolated. After switching off this energy line as well, she checked the display again. This time, the indicator remained off, confirming that the installation was fully de-energized. Only then did she begin the maintenance work.
This scenario reflects a realistic field situation. Complex electrical installations often include multiple power supplies, backfeeds, or residual voltages. Visual voltage indication on the door of a control cabinet provides an additional safety barrier within the LOTO procedure.
Electrical safety indicators provide a direct visual indication when an electrical circuit is energized. The purpose of such indicators is to reduce the risk of electric shock, arc flash incidents, and unintended start-up of installations. They also support rapid fault diagnostics.
In industrial control cabinets, voltage indicators are used as an additional verification alongside measuring instruments and test procedures. They do not replace voltage verification with a suitable measuring device, but provide a continuous visible status indication.
The Remlive RL-24i product range includes two specific applications:
-RL-24i Isolator Check
-RL-24i Phase Indicator
Both systems are designed for installation in control panels, with the measuring unit mounted on a DIN rail and the display unit installed on the enclosure door. This allows the voltage status to be visible without opening the cabinet.
The RL-24i Isolator Check is designed to monitor and confirm the presence of voltage during and after isolation of electrical installations. The system is intended for integration in control cabinets and distribution boards where maintenance activities are performed.
The circular display unit is mounted on the door of a control panel or switchgear. This ensures that all personnel can immediately see whether voltage is present. It supports visual verification within LOTO procedures and reinforces the “try-out” phase, where the effectiveness of isolation is confirmed.
The RL-24i Isolator Check can monitor voltages up to 690 VAC in CAT IV configurations.
Measurement category CAT IV refers to the highest overvoltage category according to IEC 61010-1 and applies to measurements at the source of the low-voltage installation, such as main distribution boards. This implies suitability for environments where high short-circuit currents and transient overvoltages may occur.
The display provides a clear visual indication of voltage status. When voltage is present, the display flashes at one-second intervals. This periodic pulse ensures the indication is not confused with reflections or ambient light.
The indicator shows a “live” status on the front of the control cabinet. This eliminates the need to open the cabinet door for an initial voltage indication, contributing to risk reduction—particularly in situations where opening the cabinet may expose personnel to arc flash hazards
The voltage supplied to the door unit is 3.8 V DC. This low voltage level enhances user safety. The measuring unit is installed on a DIN rail inside the cabinet, while the display unit is galvanically isolated. This prevents hazardous voltages from appearing on the cabinet door.
The RL-24i allows monitoring of individual phases, even after partial isolation of the system. The device consumes only minimal power, which is relevant for continuous monitoring.
The enclosure complies with protection class IP66. This means it is completely dust-tight and protected against powerful water jets, maintaining the integrity of the control cabinet.
The housing is made of V0-rated material according to UL 94. A V0 classification means the material is self-extinguishing and does not produce flaming droplets. In addition, the material is halogen-free, reducing smoke development and toxicity in case of fire.
The operating temperature range is -35 °C to +55 °C, making the indicator suitable for industrial environments with varying climatic conditions.
The RL-24i Isolator Check complies with, among others, the following standards and directives:
-EN 61326-1 (EMC requirements for measurement, control, and laboratory equipment)
-EN 61010-1 (Safety requirements for measurement equipment)
-UL 61010-1
-CSA C22.2 No. 61010-1
-NEMA 4X
-IEC 60204 (Safety of machinery – Electrical equipment of machines)
-RoHS 2011/65/EU & 2015/863
These compliances confirm that the product meets relevant requirements for electrical safety, electromagnetic compatibility, and material restrictions.
The RL-24i Phase Indicator is designed for monitoring three-phase power systems. The system provides a visual indication of the presence of each phase and verifies the correct phase sequence.
Correct phase sequence is essential for motors, pumps, and conveying systems. An incorrect phase sequence can result in reverse rotation, mechanical damage, or process disruption.
The Phase Indicator can monitor voltages up to 1000 VAC, making it suitable for a wide range of industrial low-voltage installations.
The door display shows the status of each individual phase and verifies whether the phase sequence matches the required configuration. Two versions are available: one where clockwise rotation is indicated as correct, and one where counterclockwise rotation is considered correct.
This distinction is relevant in applications where direction of rotation is critical, such as pump systems or conveyor belts.
As with the Isolator Check, galvanic isolation is applied between the DIN rail-mounted measuring unit and the door-mounted display unit. The door unit operates at 3.8 V DC, contributing to user safety.
The system enables monitoring of individual phases, even after partial isolation. Power consumption is low, making it suitable for continuous monitoring.
The Phase Indicator is designed to IP66, ensuring that the integrity of the control cabinet is maintained. The enclosure is V0-rated and halogen-free, similar to the Isolator Check.
The temperature range of -35 °C to +55 °C allows use in a wide range of industrial conditions.
Although both systems contribute to electrical safety, they differ in functional purpose.
The Isolator Check is primarily intended for verifying absence of voltage during maintenance or repair. It supports LOTO procedures by providing visible confirmation of voltage presence or absence. Its use is particularly relevant in situations where multiple power supplies or hidden energy sources may be present.
The Phase Indicator, on the other hand, is focused on monitoring the operational status of three-phase systems. It helps detect phase loss or incorrect phase sequence, which is essential for preventing mechanical damage and process interruptions.
In maintenance situations where safe isolation must be confirmed, the Isolator Check is the appropriate choice. In operational situations where the integrity of a three-phase system must be monitored, the Phase Indicator is functionally suitable.
Within a broader machine safety concept, visual voltage indicators can be considered an additional protective measure. They do not replace voltage measurement with a suitable two-pole tester but enhance the visibility of the energy status.
When applied in combination with LOTO procedures, they support the verification phase, in which it must be demonstrated that an installation is actually de-energized. This contributes to risk reduction, particularly in complex installations with multiple energy sources.
Correct application requires that installation and wiring are carried out in accordance with applicable standards, including IEC 60204 for machine wiring and relevant national regulations.
The Remlive RL-24i Isolator Check and RL-24i Phase Indicator are designed as industrial voltage indicators for use in control cabinets and distribution systems. The Isolator Check supports safe isolation during maintenance by providing clear visual voltage indication. The Phase Indicator monitors the integrity and phase sequence of three-phase systems during operation.
Both systems are designed with attention to galvanic isolation, low-voltage supply to the door unit, IP66 protection, and a V0-rated enclosure. Compliance with international standards such as EN 61010-1 and IEC 60204 underlines their technical conformity.
In industrial environments where electrical safety is an integral part of machine safety, such indicators contribute to increased transparency of energy status and improved risk control during both operational and maintenance activities.
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