If your not sure whether to call a Plumber or an Electrician for your no hot water issue, its generally an electrical problem.
Hot Water Heating problems are normally related to one of the below issues:
Hot Water heater Thermostat
Hot Water Heater Element
Ripple Control Relay at Meter board
Shorting within cabling
A faulty hot water heater Switch
Faulty Fuse or associated Switchboard wiring
We can Help with all of the above issues , every so often the problem for no Hot Water could be caused by a faulty Ajax Valve or a Temperature Tempering valve issue which will require a plumber to fix.