I am in the industry and they are covered as contents under your policy. Just as a television, stove, clothing, etc...
You can get extra insurance for them probably as antiquities, but if you have enough to cover the value of them in your policy then your fine. Maybe if you have some high end machines I would consider it. I have 100,000 coverage for contents and that covers the value of my machines. Thats here where I live, make sure you check the fine print in your policy though!
God forbid something happens, it's not like you can just get your cheque and goto the local electronics shop to buy new replacements!!