@ben "In all cases, gravity ensures..." so not suitable for use in space then? :)
Of course, the UK "13A socket" is actually rated for 10A continuous... but you should still have been ok with a 2KW heater. I don't think "don't plug heaters into extension cables" is particularly good advice TBH - there's no reason that a good extension cable should be any more dangerous than a good wall socket (which also usually have switches). IMHO this extension cable is substandard since it claimed to be 13A
@ben I have some Aliexpress smartplugs which claim to be 16A, despite having a 13A UK plug on one side and 13A UK socket on the other... I'm absolutely sure they aren't CE/BS certified, and no I'm not going to try putting 16A though them!
FWIW, people who need to charge an EV through an extension cable seem to recommend cables sold by Toughleads. Although your experience does show that pulling large currents continuously through even a brand new and properly rated 13A socket isn't without risk.
I suspect the advice about extension leads is probably driven more by it involving additional physical connections (so more to be loose etc) and the risk that someone'll then plug a hoover into a spare socket.
You're right though, it absolutely should have coped - it claims 13A @ 250v (3.2kW) and we were well under.
@ben I would be tempted to send it back to tesco (possibly together with a copy of your analysis) - despite the design causing the switch to fail safe, I certainly wouldn't want to rely on that happening before the plastic catches fire, so they are selling a fire risk (if they think you shouldn't plug high power stuff into an extension, why label it as suitable for 13A?). Although its interesting that there are neons soldered onto the hot bits and it looks like the solder didn't melt.
@ben The advice not to plug EV chargers into extension leads mostly seems to be because most EV granny chargers have thermisters in the plug to detect an overheaty socket, and that obviously can't protect the wall socket if its plugged into an extension instead.
@ben Well, an EV charger is about the biggest continuous load you're going to plug into a 13A socket. Kettles might draw more, but only for short periods, but if you're charging your car with a granny charger you could well be pulling a continuous 10A for 24 hours straight. (As mentioned, UK sockets are rated for 10A continuous, and there's always the concern that an old socket might have loose fitting or corroded contacts, so very possible it isn't up to doing the rated current)
@ben@steve Minor point but your calculation of the current as 8.69 A is a possible underestimate.
If the heater is rated at 2 kW at 230 V then its resistance would be 26.45 Ω. If the mains voltage is at the maximum allowable value (251 V, it could actually be higher in practice - though you have PV so would probably notice if it was) then the current would be 9.49 A which is getting close to the continuous rating of the sockets and leads.
An EV charger wouldn't be a simple resistive load so would likely actually draw less current at 251 V, assuming it follows a power limit. It might actually draw more current at the lowest possible voltage though I suspect they're bright enough not to do that. Wouldn't bet on it, though, without confirmation.
@edavies@ben I usually charge on a single phase type-2, rated at 32A. If the EVSE tells the car to draw 32A, that's what my car seems to draw, regardless of the voltage. So on low-voltage days, the EVSE screen shows 32A but a lower KW power than on high-voltage days. Although not a resistive load, I guess the charger can tune itself load pretty well to stick closely to the current limit, regardless of the voltage. I rarely use a granny charger, but I can't imagine it would behave differently.
Add comment