A retrofit energization arrangement especially suitable for an aircraft wherein original factory-placed wiring can be reused in common bus form for plural new loads in order to avoid the expense and hazard of disassembling original wiring bundles for new conductor incorporation. Serviceable wiring possibly earlier retired in place or becoming unneeded from equipment removal can, by way of the invention, be used for plural diverse new loads including loads of disparate operating cycle and current requirements for example, even though energized via a common bus. In the disclosed apparatus both energizing current and load control signals are transmitted via the same electrical bus between control location and load areas of the aircraft where control decoding and energy tap-off occur, the latter by switch mode power supply if needed. Control signals of sinusoidal waveform, minimal electromagnetic and radio frequency interference character and limited existing bus filtering attenuation are disclosed; these may be embodied as the Frequency Shift Keying (FSK) or Continuous Tone Coded Squelch System, CTCSS, frequencies used in the radio communication art. Loads of differing types are disclosed as examples in the described embodiment of the invention; additional loads are feasible. Use of the invention in land vehicles, watercraft and building structures is also contemplated.