In most cases, no. Many portable heaters require more of the capacity of a circuit.
Ceiling fans are required to be installed by use of a special fan rated junction box only.
You would have to turn the circuit breaker to the off position first, before you could turn it back
We recommend that you turn them off at the circuit breaker. It’s safer. Immediately, contact a licensed electrician and the electric power company.
Electric meter bases, service entrance wiring, and interior wiring are jobs that are to be performed by a licensed and insured electrical contractor or company.