Watts to Amps Calculator

Every time a business adds new machinery, an EV charger, a heat pump or a process oven, the first electrical question is the same: what current will it draw, and is the existing cable and breaker rated to carry it. Converting nameplate watts into amps at the right voltage and power factor is the starting point. A 22kW three-phase EV charger pulls around 32A per phase at 400V, which means a 32A breaker is the minimum, with cable sized for the run length to keep voltage drop inside the 5% limit set out in BS 7671.

Mid-market businesses adding capacity at multiple sites need consistent answers across the portfolio. A 50kW process load installed at six bakeries will draw the same current at each site, but the cable run, the ambient temperature and the grouping with other circuits will all be different. The watts to amps conversion gives the consistent reference point. From there, the local design engineer applies the derating factors and signs off compliance against the regulations, with the documentation ready for the next periodic inspection.

Purely Energy helps facilities and operations teams plan capacity additions across multi-site portfolios. We sit between the equipment specification and the supply contract, making sure that when a site adds 100kW of new load, the MIC reflects it, the supply transformer can deliver it and the tariff shape captures the new consumption pattern. We do that work across 30+ panel suppliers, so the procurement decision is not constrained by who happens to have account managed the client last year.