Electric Boiler
fuel burning burners uses both fuels(such as oil, natural gas, and oil) and electricity. The heating element are fuels and controlling elements are electricity, which typically for residential 15A wire is sufficient to run the control circuitry and pumps. So if there is electric failure the boiler will not function

Electric boiler uses electricity for both heating component and control circuitry. A typical 100 A is needed for the boiler for about 70,000 btu/hr

So to have a boiler such size in common houses you need 200A service panel.
advantage of electric boiler

  1. it is clean energy.
  2. no flue gases are created thus no carbon monoxide, NO(nitrogen oxide, which may has bad smell, mainly for the neighbour), and any other gases. So you are always safe
  3. the probability of fire is less
  4. it does not need venting the flue to outside, so it can be installed almost anywhere.
  5. it is 100% efficient(as all electricity is directly converted to heat)
  6. the cost of installation is less as there is no need for gas license to install it

Disadvantage
Electricity is more expensive than fuels, about three times more

A typical electric boiler installed