The PT73 is a device that can provide additional protection to our units. Its use is recommended on systems where there are large surges and fluctuations in 230 Vac power supply. Moreover, it is very effective in cutting the peak voltage that is generated when you closed the MV switch, thanks to a turn-on delay. The device can be easily installed inside the panel through the DIN EN50022 rail. A red led indicates the possible intervention of fuses.