In standard residential or building electrical installations, personnel safety against mains voltage is ensured by a Residual Current Device (RCD) combined with an earth rod. However, this protection is not effective when 230Vac is supplied by an AC power generator, such as a DC-AC inverter or a generator set. These systems create what is known as a floating network system.
The VTB Insulation Monitor: The Only Safe Solution
The VTB Insulation Monitor 25-1 / VTB 230-25 is specifically developed to guarantee personnel safety in a floating network system, as required by the NEN 1010 standard.
In this type of network, no RCD (not even Class B) offers sufficient protection, especially when power is used outside the mobile unit. The VTB Insulation Monitor solves this by continuously measuring the insulation resistance and immediately shutting off the 230Vac power as soon as an unsafe situation is detected.
Application and Legal Necessity
This protection system is crucial for:
The insulation monitor is mandatory for driving and movable units used commercially (e.g., company vehicles, market stalls, site cabins, and fire engines).
Liability: The employer is obligated to guarantee a safe workplace. Without a VTB Insulation Monitor, the 230Vac cannot be switched off in case of a fault, leading to very serious consequences. Installing the VTB 25 resolves the entire issue surrounding personnel safety.
Although caravans and RVs do not fall under this legal obligation, the danger is identical. For beach houses, tiny houses, and garden sheds where an earth rod is missing or impractical, the VTB 25 also offers a simple and safe solution.
The VTB Insulation Monitor is easily mounted between the output of the AC power source and the loads.
Integrated Systems: The VTB 25 model is suitable for use with inverters featuring an integrated transfer relay, such as a Victron MultiPlus (charger and inverter in one), thanks to its capability to connect the required mains voltage detection.
Technical Specifications (VTB 230-25)
