Mersen Terra SPD & GMD

Mersen TERRA SPD (Earth status indicator SPD)

Monitoring the grounding system in the surge protection device itself

For the protection to work properly, the correct status of the grounding system in an electrical installation is essential.
DID YOU KNOW that nobody knows what percentage of installed surge protection devices are providing good protection?
TERRA® is the first protection device on the market that, in addition to indicating that it is properly wired, guarantees that there is an adequate path to ground, which is essential if the protection device is to shunt the energy peaks to ground effectively.

The premium solution for the most demanding installations
TERRA®’s simple information makes it the ideal solution for both unskilled personnel and maintenance professionals specialised in ground connections.
It helps to avoid situations that might cause power cuts and repair costs, with the resulting damage to your brand image.
It provides additional information about the grounding system, with potential synergies for protection and safety in general, not just for surge protection

Why Surge-Trap® TERRA ?

In the surge protection industry, one can find several examples of combination / integration of 2 functions in 1 single device:

• Mersen outstood as the World’s first mover by combining transient and power frequency overvoltage protection (SPD+POP)
• Some other manufacturers have combined SPDs with MCBs or RCDs, etc.

However, nobody had so far addressed a true potential issue with surge protection devices, which has to do with the fact that the SPDs themselves may neither be installed correctly nor operating under conditions of maximum effectiveness.

GMD – Ground ( Earth )monitoring devices

GMD® is a control device that continuously monitors the state of the ground connection:
• Ensures proper operation of surge protection devices (SPDs) that discharge energy through the facility ground connection.
• Provides additional safety information to avoid indirect contact.
• Reduces preventative maintenance costs.

By the loop resistance calculation method, GMD® checks the impedance of the actual leakage path of an indirect contact, enabling it to detect the following possible incidents, both in the installation itself and in transformer centre to which it is connected:
• Deterioration of the ground connection due to ageing of the earth rods, due to theft or increased soil resistivity during dry periods.
• Breakage or incorrect wiring of the neutral cable.

Ratings and features

The system of grounding measurement by loop impedance can be applied to the various neutral configurations: TT, TNS and TNC-S
• Un (L-N/L-L): 120/208 V, 230/400 V
• Monobloc DIN rail format
• Alarm function on the ground value (PE). Activates the output if it detects a value shown on the display exceeding a maximum preset by the user
• It provide real time value of earth & its loop
• Any deviation from the set value will be indicated through Alarm
• Possibility of creating alarm function ,out side the panel or at any Monitoring station
• Easy to install in DIN RAIL in panels.