I have 20 amp sockets in my kitchen (as all newly built housing has, really) but there are no 20 amp kettles on the market. I wish I could get that extra 600 watts or power :(
No it's not. It's just against code if they use a NEMA 5-15 outlet. If GP used NEMA 5-20 outlets and the appliance used a 5-20 plug, then there's no issue.
Many commercial appliances use 5-20 plugs. Also, lots of commercial cleaning equipment seems to use 5-20, which is why you see businesses tend to only use 5-20 outlets.
I'm not aware of any kettles that use 5-20 plugs but I bet they exist somewhere.
IIRC NEC requires 20 amp circuits for the kitchen. However the only time I've seen a 5-20R in a residential kitchen is after the electrician got done with mine (he insisted code required the 20 amp receptacles).
It's not required, but it is allowed. And, the only thing you need to do is swap a 5-15 for a 5-20. No other work needs to be done and it's all compliant.
The circuit rating is 80% of nominal for continuous loads - runtimes of 3 hours or more - according to NEC in the US. Not sure what you mean by “regular appliance”; there is no such definition by code.
A kettle is fine at a full circuit load for under 3 hours.
It's not, and for laymen "continuous load" has a specific meaning in this context. It means something that runs for 3+ hours continuously, without a break.
Well they can be, until they boil dry, and the thermal cut out kicks in.
Prior to the late 70s / early 80s so called "automatic kettles" were not necessarily all that common in the UK, and one had to manually switch them off.
I certainly recall a time or two with a kitchen full of steam due to forgetting about putting the kettle on.
There are regional differences that are probably causing some confusion. In the US, breakers have a nameplate rating 25% higher than their continuous load capacity. Go to Australia, for example, and the identical breaker will have a nameplate rating 80% of what it would in the US.
So you can run indefinitely at the nameplate rating in Australia, but only 3 hours in the US. And the startup current (inrush) can be much higher than the rating. Most breakers are thermo-magnetic. The magnetic part has a much higher tripping point and allows for inrush current. The thermo part trips when it gets too hot, and that'll be the current printed on the breaker.
Practically speaking, any intermittent device that _can_ run continuously or can fail to a continuous needs to be considered as such for safety purposes.
For example, a fridge should only run the compressor intermittently, but it has two obvious cases where the compressor could run indefinitely:
* An influx of heat, like filling an empty fridge with room temperature cans.
* A door being left open.
In the case of the kettle, it will likely be evaluated against it's "nominal" draw after the initial startup. If the auto-off sensor were to fail, it could run continuously at the tempurature.
I probably can’t speak to your jurisdiction, but no electrical inspector I’ve ever met would consider those loads continuous - in its precise, non-colloquial meaning - for the purpose of rating the circuit.
An appliance manufacturer may be under different UL regulations for failure modes of a device on a specific rated circuit. I don’t know anything about that.
Even in the context of your refrigerator example (which I don't necessarily agree with), a kettle should have two thermostats - a primary one that keeps the temperature setpoint, and a safety cutoff in case the primary stops working. In both fail and the kettle is somehow drawing its nominal power for hours at a time, the main safety hazard is going to be the kettle itself trying to dissipate >1Kw.
Yes, laymen and non-experts are going to use words to mean the wrong thing. NEC defines continuous load as 3 or more hours of uninterrupted demand. If you want to use the amateur definition, go right ahead, but understand there's an accepted industry definition of that term, even though it looks just like normal words. :)
If this is the standard then everything is a continuous load. A soldering iron or a hair dryer or a blender might get left on forever, who knows. Maybe I want the microwave to run 24 hours a day. If everything is a continuous load, why would the NEC make a difference at all?
I would install an US 240V@20A receptacle and replace the plug on the kettle.
You can also wire a duplex 120V with the two phases (you might find this in some kitchens, and in my workshop). Then you can make a dangerous extension cord adapter combining the split phase 120V into one 240V female plug.
