An electric heater with a metallic outer casing is rated at 1.1 kW and is designed to run on the standard UK AC mains supply (230 V rms, 50 Hz).
Which row correctly identifies the rms current IrmsI_{\text{rms}}Irms drawn by the heater, the minimum suitable fuse rating from the standard set {3 A,5 A,13 A}\{3\text{ A}, 5\text{ A}, 13\text{ A}\}{3 A,5 A,13 A}, and whether the mains cable must include an earth wire?
Irms=4.8 AI_{\text{rms}} = 4.8\text{ A}Irms=4.8 A; fuse rating = 5 A5\text{ A}5 A; earth wire required = Yes
Irms=4.8 AI_{\text{rms}} = 4.8\text{ A}Irms=4.8 A; fuse rating = 5 A5\text{ A}5 A; earth wire required = No
Irms=6.8 AI_{\text{rms}} = 6.8\text{ A}Irms=6.8 A; fuse rating = 13 A13\text{ A}13 A; earth wire required = Yes
Irms=4.8 AI_{\text{rms}} = 4.8\text{ A}Irms=4.8 A; fuse rating = 3 A3\text{ A}3 A; earth wire required = Yes
