Electrical shock is the major factor contribute to injury and more serious death statistic for electrical incident around the world.We can’t assume are is present or not because it is not visible and can look with naked eyes.
Electrical safety principle is to keep away person from live voltage.For electrical person,they need to clarify voltage value is safe or not before proceed any maintenance and repairing activity to avoid electrical shock using a multimeter.
To minimize the electrical shock incident,some country have the new standard and regulation for machine and power panel safety installation such as to install the Voltage Verification.It can show the voltage status for the machine or control panel with visual LED indication.
How this Voltage Verification operates?
A voltage indicator uses a high impedance voltage detection circuit per phase to sense and illuminate AC/DC voltage. The illumination of the LEDs occurs only when current passes through two of these voltage detection circuits.
Envision four voltage detection circuits (L1, L2, L3, GND) “meeting” each other in the center.Below is illustration for Normal and Failed condition.
Voltage Verification Wiring Diagram and installation
Usually the voltage verification are installed at incoming power supply after the circuit breaker.We also can install at outgoing power supply for double protection.It depend on design and how critical for our electrical application.Below is basic wiring diagram for Voltage Verification.
In the market now,we can choose many types of Voltage Verification.For this post i would like to introduce the voltage verification designed by GRACE ENGINEERED.They have several models and i choose the R-3W model.I already installed for a new machine and panel at my factory and this device is added in the new regulation for machine safety.