Will the outlet be connected to an inverter? Or only when on shore power? If the latter, then it shouldn't matter because the main use of the VHF is when sailing or at anchor and there's no AC there.
One way to test might be to place an extension cord near the VHF and power up the VHF and some AC device. Look for the instructions the USCG put out last year about checking for LED interference do the same with the AC device powered up. A note, a lot of AC noise is caused by the device, say a motor running, than by the AC it self.