BS EN 50065-4-7. Signalling on low-voltage electrical installations in the frequency range 3 kHz to 148,5 kHz. Part 4-7. Portable low voltage decoupling filters. Safety requirements|Safety measures, Signals, Electrical protection equipment, Electric plugs, Electric connectors, Low-voltage installations, Signal transmission, Electrical equipment, Mains electricity supply, Electrical installations, Electric sockets, Protected electrical equipment, Electric filters, Electrical safety, Low-voltage equipment