WiFi plug question

[winston1]

Heaters are NOT reactive loads so should be OK.

 

[bernardgreen]

Heaters are NOT reactive loads so should be OK.

The resistance when cold will be lower than when at operating temperature. Hence at switch on the load may be higher than the rated load until the heater reaches it's operating temperature.

As already mentioned remote switching of heaters can create a risk of fire.

 

[JohnW2]

The resistance when cold will be lower than when at operating temperature. Hence at switch on the load may be higher than the rated load until the heater reaches it's operating temperature.

I though that heatg elements usually used Nichrome or similar, which has an extremely small temperature coefficient of resistance? If so, whilst what you say is qualitatively true, in practice there would be very little difference in resistance (hence current) between hot and cold.

Kind Regards, John

 

[bernardgreen]

in practice there would be very little difference in resistance

There are self regulating heaters, the element(s) maintain themselves at a fixed temperature by varying the current through themselves. They can have a high ratio of hot to cold. That said they are not common in domestic use.

Water heating is one applocation https://www.traceheatinguk.co.uk/domestic-hot-water-maintenance-trace-heating

 

[JohnW2]

There are self regulating heaters, the element(s) maintain themselves at a fixed temperature by varying the current through themselves. They can have a high ratio of hot to cold. That said they are not common in domestic use.

Fair enough, but that's not really what I was talking about.

I was responding to your comment about the difference (of resistance/current) when cold ("at switch on") and when at running temperature - which, as I said, one would not expect to be much different if the elements used a material such as nichrome.

Kind Regards, John

 

[Mottie]

I’ve looked inside both heaters, they are very lightweight and the elements are as thin as a spiders web - they don’t glow or anything.
This is the 3Kw one, the 2Kw is similar. https://www.bagoftools.co.uk/home-e...MIh4GymOPA1wIV4ZPtCh2PrwUpEAQYAyABEgJH2_D_BwE

 

[bernardgreen]

Heater, a wide definition covering an enormous range of types and sizes of heat generating equipment.

Making a statement " this remotely controlled socket can be used to supply a heater " does not discriminate between the types of heater.

Can we assume that all heaters are nichrome elements ? We can assume it and then be very surprised when things go wrong because the heater involved did not use a nichrome wire element.

 

[Lectrician]

It’s for safety reasons. Turning a heater on remotely that could have been knocked over by your dog for example.

 

[Mottie]

Okay thanks. But is the possibility of a fire on an unnatrnded fire the main reason? The plugs have an on/off button which I will be using during the day to run the heaters - are the sockets man enough to run a 2kw and a 3Kw heater? They won’t melt or catch fire will they?

 

[Lectrician]

Why don’t you ask the manufacturer their reason? I’m happy it’s a safety reason due to unattended portable appliances.

 

[Mottie]

I might try but my Chinese is probably not up to much lol.