The weakest part of an electrical circuit is its earthing integrity and hence the most important aspect from an electrical safety perspective. Yet once designed & installed, we often forget to verify its integrity! When was the last time you verified the integrity of the earth stake at your home?
In truth, even we in the industry overlook it yet frontline protective devices RCD’s/RCBO’s, require a low impedance earth path in order to provide electrical protection and when not present, electrical safety can be compromised.
A ‘good/low impedance earth’ may be compromised by many factors including corrosion, hot joints and aging installations but by far the most variable and overlooked is the ground itself.
Soil types such as sandy/rocky environments, concrete and bitumen pose a real problem making a low impedance environment difficult and at worst impossible to achieve. Add in moisture and environmental changes and the problem is exacerbated.
Unearthed or IT systems are also problematic for RCD’s due to lack of an earth-path and the 1st and 2nd fault scenario. Although widely regarded as the safest earthing system, they are not widely used as a result.
Our RVT-VMD device is designed to accompany any RCD/RCBO and provided 'additional layers’ of electrical protection.
Our RVT-VMD device enables enhanced electrical protection within the TN (MEN), TT earthed systems and uniquely IT unearthed systems. Importantly, our Technology enables protection against the non-dangerous IT 1st fault condition. This allows the ‘Bird on the Wire’ concept to become a reality and effectively removing the human from becoming part of the electrical circuit.
When the RVT-VMD device is operating in an IT or floating environment, the device essentially becomes the centre tap/reference point of the transformer, being held at zero volts.
The RVT-VMD is detecting a voltage rise from an insulation breakdown on either L1 or L2 onto the frame being protected. When a voltage above the trigger level of 43V is detected, the device causes a 33mA imbalance across the RCD which isolates the circuit. When this occurs, 8mA of fault current flows with isolation occuring in under 20mSec.
The RVT_VMD device is an electrically connected ‘add-on’, creating an imbalance across the RCD/RCBO when a voltage leakage to earth/frame is detected, complementing RCD’s in ‘bad earth’ environments, un-earthed installations or applications including portable generators, power inverters and UPS.
Other benefits of RVT-VMD include ‘Polarity Sensitive’ and protection against ‘loss of neutral integrity’ on the supply side of the MEN point, the biggest cause of electrical shock in Australia.
Our Residual Voltage Tehnology (RVT-VMD) device mitigates electrical safety risk, especially personal protection, by ‘monitoring the earth/frame’ for a broader range of fault detection.