Electrical – I have a heater in a 3 phase (415V AC, 230V per phase) timber kiln drawing 43A per phase. How many kW is this


I'm new to this subject, but I want to learn. I have an electric heated timber kiln and I want to replace the electric heater with an equivalent rated oil burner, therefore I need to calculate the output power of the heater from the available information. The electric heater has an input of 3 phase 415V AC, 230V per phase. The amps per phase when the heater is running is 43A.

Is the power = 230V x 43A x 3 = 29670W ?

Best Answer

Your calculation is correct. You have 30 kW of electrical heating.

For rough oil calculation you can work on a figure of 10 kWh heating per litre of oil. For 30 kW oil heating you will burn 3 L/hour assuming 100% of heat gets into the kiln. De-rate for flue losses. 85 to 90% is probably a good value for a condensing boiler.

But why do you want to burn non-renewable oil? Shouldn't you be burning renewable timber? Timber will give you about 4 to 4.5 kWh/kg and you're already in that business.