Calculator · amps / kW
Heater amps
Convert heater kW into current at 110V, 230V or 400V and check 13A, 16A, 32A and three-phase supply classes.
A quick check before choosing electric heaters or splitting loads.
Guided job flow
Site Heating Power Check
A guided flow for answering: can this site supply run the electric heaters without overheating cable reels, dropping voltage or overloading one phase?
Flow steps
- Select 13A, 16A, 32A, 63A, 110V transformer, generator or three-phase supply.
- Add heater kW or choose equipment presets.
- Run amps, transformer, cable reel derating, voltage drop, RCD leakage and phase balance checks.
- Export a site power note and equipment category links.
Tools in this flow
Tool index
Calculator · 110V / site transformer
110V transformer heater check
Check whether a 110V site transformer can realistically power temporary heaters, dehumidifiers, fans or drying kit without overload or unacceptable voltage drop.
For construction sites, drying contractors and hire desks using 110V heaters or 110V drying equipment.
Calculator · extension lead / cable reel
Heater cable reel derating
Check whether a coiled, partly unwound or long extension reel is a bad match for a 2kW or 3kW temporary heater.
For heater setups using 13A plugs, 16A commando leads or long extension reels.
Calculator · BS 7671 / voltage drop
HVAC voltage drop envelope
Estimate voltage drop over long leads for heaters, air movers, dehumidifiers and portable AC, with compressor start warnings.
A planning aid, not a certification cable design package.
Calculator · RCD / earth leakage
RCD leakage budget
Estimate cumulative leakage from compressors, dehumidifiers, portable AC, heaters, pumps and long wet leads before stacking everything behind one RCD.
Use it when drying or cooling equipment trips randomly or when several items share one RCD/RCBO.
Calculator · three-phase / phase balance
Three-phase load balancer
Allocate single-phase heaters, dehumidifiers, fans and portable AC units across L1/L2/L3 to reduce imbalance and nuisance trips.
For 32A, 63A and 125A temporary distribution boards with mixed 230V loads.