Most ham radio equipment operates on 12vdc. AC brings noise, so aside from dedicated external power supplies, you won't see much AC-powered equipment.
The maximum power a ham can transmit is 1500 watts. You don't need a 220v circuit to draw 1500 watts, and the majority of hams operate with less than 200. If there is 220v equipment in there, it will be the first I've ever seen.
Don't turn on any transmitters or amplifiers, especially if they aren't connected to an antenna. You can damage the transmitter. Powered on, there is some risk of RF burns should you contact antenna feedlines while transmitting. While any transmitter is powered on, treat all antenna connectors like power outlets. With the transmitter off, they are safe.
Ham radio can be anything from a couple handheld radios to entire rooms full of transmitters feeding acres of antenna arrays. Without knowing what you're dealing with, it's hard to identify any specific risks.