The same heater is a different load in a different country
A "2000 W heater" is not a fixed current. It is 8.7 A on a 230 V supply and 16.7 A on a 120 V supply. That single fact explains most of the confusion, and most of the melted plugs.
In the UK and Europe, a 2 kW convector or oil-filled radiator is an ordinary load that a 13 A plug is built for. In North America the same 2 kW would be an extraordinary load, which is why US space heaters are almost always 1500 W — 1.5 kW at 120 V is 12.5 A, right at the useful limit of a 15 A household circuit.
So the first question is never "will this plug handle 2000 watts". It is "how many amps, on what voltage, for how many hours".
The number printed on the plug is optimistic
Most cheap smart plugs carry a 10 A rating. Better ones say 13 A or 16 A. What the small print usually means is a resistive peak under test conditions, not a continuous duty figure.
Apply the continuous load rule — a load that runs for three hours or more should sit at roughly 80% of the rating — and the numbers get uncomfortable:
- A 10 A plug is realistically an 8 A continuous device. A 2 kW UK heater at 8.7 A already exceeds it.
- A 13 A plug handles the 2 kW UK heater, but not a 3 kW one (13.0 A), which is why fixed appliances in the UK stop being plug-in devices at all.
- A 16 A plug on 120 V handles the US 1500 W heater at 12.5 A with a little margin, and nothing larger.
This is also why the US 1500 W figure is not a marketing coincidence. It is the largest heater that fits inside a 15 A circuit with the 80% rule applied.
Heaters are the easy case, and it still fails
A heating element is a resistive load, and resistive is the easiest thing a relay can switch. There is no inrush spike to speak of, because a cold element is already low resistance and simply draws its normal current immediately.
And still the plug fails. The reason is not the switching, it is the duration.
A relay contact has a small resistance. Current through it makes heat. Heat raises the resistance a little, which makes more heat. In a closed plastic housing, with no airflow, at 90% of rating, for six hours a night, that loop settles somewhere hot. The failure is not dramatic — the plastic discolours, the housing softens, and one day the contact welds shut and the heater will not turn off.
That is the failure you should be designing against, and the only defences are derating the plug properly and buying one that is rated for the market you are in.
The loads that are genuinely hard
If the resistive case is the easy one, the hard ones are:
- Fan heaters and anything with a motor — the motor's inrush is several times its running current, and that spike is what welds contacts.
- Compressors — dehumidifiers, portable air conditioners, fridges. Highest inrush of the common domestic loads.
- Pumps and any inductive load — the inductive kick at switch-off erodes contacts over time.
A plug that has survived a 2 kW panel heater for two winters can still be destroyed in one season by a 500 W pump, because the pump's problem is not the watts.
Two things not to do
Do not daisy-chain. A smart plug into an extension lead, or into another smart plug, puts two contact resistances and two cable runs in series, and the joint that gets warm is the one nobody is looking at.
Do not put it on a ring or a shared circuit without thinking. In the UK, a 13 A plug into a socket on a 32 A ring is fine for a load the plug is rated for, and it is not fine for a 3 kW heater running alongside other loads on the same ring. In North America, two 1500 W heaters on one 15 A circuit is a guaranteed breaker trip, and a space heater plus anything else on the same circuit is marginal.
What to look for
- A printed continuous rating, for your market — 13 A BS 1363 in the UK, 15 A in the US, 16 A in the EU. Not a bare "10 A max".
- A relay, and ideally a stated resistive load rating.
- A thermal cutoff or at least a housing rated for the heat it will make.
- The right plug for the country — a UK 13 A fused plug is a physically different product from a US 15 A one or a Schuko, and the rating follows the plug.
If the heater is fixed, or it is 2 kW or larger, the honest answer is that it should not be on a plug at all. It should be on a dedicated circuit behind a properly rated switch, which is a different job and usually an electrician's.
Where to start
For plug-in control of a load a plug can genuinely handle, the market-specific versions matter more than the headline number. The UK 13 A Wi-Fi plug-in socket and the US socket are the same idea built to two different standards, which is the whole point.
The rest of the range, with their ratings listed, is in the smart socket category — worth reading the current ratings across them before choosing, because the spread is wider than the prices suggest.
Build and rating detail from the manufacturing side is on XingLiao's factory site.
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