Energy & electrical
Resistive heater current
- where
- current (A)
- heater input (W; any unit you pick is converted)
- supply voltage (V)
Explain this equation
Works out the current drawn by a resistive heater such as an immersion element. Use it as a starting point for checking circuit loading.
P is the heater input power. U is the supply voltage. I is the current.
For a resistive load the current and voltage are in step, so power is simply voltage times current. Dividing power by voltage gives current.
Sense check: a 3 kW immersion on 230 V draws about 13 A. A 6 kW load would draw about 26 A.
Watch out: single-phase resistive loads only. Cable, protective device and installation must be selected separately to the regulations.
Enter your values to see the result.
Good to know
Single-phase resistive load only, power factor approximately 1. Cable, protective device and installation selection are separate.
Sources
Results are arithmetic only. Worked examples are not recommended design settings. This library does not provide automatic gas pipe selection, live gas tightness tests, purging procedures, combustion acceptance limits, installation approval or commissioning certification. Manufacturer data and the applicable current method remain essential.