3 kW heater and 13 amp plug checker
Why a 3 kW heater is a tight fit on a UK 13 amp plug/socket and what to check before use.
Quick answer
A 3 kW heater is a tight fit on a UK 13 amp plug/socket. At 230 V, 3,000 W is about 13.0 A before fans, chargers, dehumidifiers or any other same-time load are counted.
Typical example
A 3 kW heater plus an 80 W fan is roughly 13.4 A. That is above a 13 A rating and well above an 80% planning warning point of 10.4 A. A 2 kW heater plus a small fan is closer to 9.0 A.
Run time changes the decision
A short supervised test is not the same as running a high plug load for hours. Sustained heat, loose contacts, old sockets, long leads and cable reels all make the plan less forgiving.
Plug and lead condition
Stop if the plug, socket, fuse carrier or lead is warm, hot, soft, melted, cracked or discoloured. Treat that as a visible condition to report, not something to normalise.
Practical alternatives
Use a lower-wattage heater, stagger other loads, confirm a separate circuit, or arrange a 16 A/32 A supply if the heating plan really needs that much input power. Do not solve it by adding adaptors.
Handoff note
Send the heater wattage, plug/socket rating, run time, other same-time loads, lead details and visible condition notes to the supplier or competent electrician. The dedicated checker builds this calculation trail.