Block st 400v to 230v transformers block st 100423 the block 100va transformer 400v to 230v is a low inrush current control safety or isolation current transformer with screw connection terminals designed with a very good switch on behaviour thanks to reduced starting currents plus high performance for the volume thanks to compact design this high quality tranfsormer also has excellent corrosion protection and low noise thanks to blockimpex vacuum impregnation block st 100423 100va