The PFS 6 Master TFR surge protector is making a noise, is this normal? With this surge protector model, a noise may be produced if the socket is not correctly set. There is a potentiometer behind the appliance in the range of 8 W to 70 W. Consult the product user guide to make the adjustments needed for installation. Once correctly set, the noise disappears. Should the problem persist, contact the INFOSEC UPS SYSTEM after-sales service on +33 (0)2 40 72 15 82 or at hotline@infosec.fr