Ddj RZ disconnecting - USB interference?

Hi. My DDJ RZ can be working fine for 20 minutes to several hours and then it will suddenly show in Rekordbox as being disconnected meaning I lose all sound until it shows as reconnected. The controller itself does not switch off but does show like it's not connected to the pc for a few seconds (jog wheel graphics indicate that no tune is loaded) I have worked out that this is being caused by electronic appliances elsewhere in the house being switched on or off and last night it happened when my son, who was in the room with me tried to connect his Bluetooth headphones to his mobile phone. I am using all the original manufacturer's leads .... could it be that it's EMP/EMI causing the problem and I require a ferrite sheilded usb lead? Or is there something else going on?