On the ship I am most familiar with that AC/DC power supply is located near the GMDSS but in a separate room. Aside from the power supply that room also has some other comms related gear. Both the power for the SAT and cable run for dish antenna for the internet goes through there as does the power supply for the LRIT, the antenna tuner for MF/HF.
It’s a convenient place for cable runs etc so that’s where they went… A central location of some mischief perhaps.
It’s sort of an electrical distribution room as both AC and DC come in and 24 volt supply to leaves. Also has some comms cables.