can you get thermal cut out safety plugs?

chilswelluk

Does anyone know if you can get thermal cut out safety pugs that monitor the temperature in the plug, and if it gets too high the plug will stop conducting?  This is different to a surge protector that has safety cut out for surges, but what I want to know is if anything exists specifically for temperature?  Although not specifically a thermal cut out device, but a surge protector - Masterplug sure protectors claim to have a thermal cut out function:
https://groceries.asda.com/product/extension-leads-cables/masterplug-piano-black-usb-power-1-socket-surge-adaptor/1000004372002
But I have no idea of the technical specs of this, or at what temperature it will cut out.  Whats more, not sure if anyone makes a dedicated thermal cut out device?

Neil_Jones

From the manual of another product from the same manufacturer:

"Repeated low surges over a period of years or one high surge can lead to the components in the surge protector degrading. This can lead to temperature rise and combustion. All Masterplug Surge Guard products have a safety thermal cut-out to protect against this eventuality"

However as a general rule if a device develops an electrical issue then the safety feature of the RCD/Fusebox will get involved.

chilswelluk

as a general rule if a device develops an electrical issue then the safety feature of the RCD/Fusebox will get involved.

Not necessarily, I have top branded MK electrics in my house (sockets, consumer units etc) along with new wiring and have had faulty chargers melting at the plug, which could have been a fire hazard.  At no point did this trip the RCD. That's why a dedicated thermal cut safety plug would be useful.  This would simply monitor the temperature at all points in the plug and then stop conducting if a threshold temperature is reached. 

Yes some of those surge protectors advertise thermal cutout, but they are sketchy about the technical details and the temperature thresholds.  I even read a post of some guy who melted something in one of these plugs, so not sure how good they are as a thermal safety device.

I can't understand why nobody makes such a thermal safety plug.  My electric car granny charger, has temperature monitoring built into the plug and if it gets too hot it will stop conducting.  It works perfectly.  I must be able to buy a dedicated safety plug that operates in the same way?

avoidtheupsidedownbottles

Do you mean socket rather than plug?  Most chargers are a brick incorporating their own plug so a separate protected plug wouldn't help. 

Neil_Jones

Well if nobody makes them there is clearly no need/ability for them?

The existing safety features such as the RCD tripout, the fuse in the plug and the safety design of plugs would appear to be doing the job sufficiently for safety purposes, but they are concerned with the flow of the electric as opposed to the heat inside the plug.  A hot plug implies that more power is being drawn which should eventually trip the RCD as an abnormal load, but by the time the required load is reached to trip it, its usually too late.  Normally an issue with the wiring inside the plug causes arcing.

Your granny charger in a nutshell is just a converter, it can monitor and do what it likes, whereas to apply that same functionality you're speaking about to the electrical system most likely requires a change to the standards and a need for backwards compatibility with existing plugs/electrics.

chilswelluk

Your granny charger in a nutshell is just a converter, it can monitor and do what it likes, whereas to apply that same functionality you're speaking about to the electrical system most likely requires a change to the standards and a need for backwards compatibility with existing plugs/electrics.

If anyone is interested, a guy at the link below tore down a plug from an electric car charger and repackaged it in a masterplug. What he found was a couple of thermistors.  I don't think it would be too hard for me to make a device with a thermal cut out feature, but I'm just surprised nobody sells anything like this on the market.  If you check reviews on Amazon it is full of pictures of cheap electronics where the plugs have melted etc.  Granted these cheap electronics should not be sold and are made with inferior materials / quality control, but something like the safety RCD plugs sold for lawnmowers with a thermal cut out would make things safer.  Another approach is you could even have some sort of tiny smoke detector which could remotely disconnect power.
https://www.speakev.com/threads/delphi-granny-charger-repair-ic-cpd-aptiv-240v-10a.145484/

Neil_Jones

Well all I can say is if you think you've spotted a gap in the market, Dragon's Den is that way

(my cut is 10% by the way )

forgotmyname

If the plugs getting that hot you are likely to be pulling more than the plug/socket is rated for. 13Amps at least.

It was deemed dangerous to let people fit their own plugs some years back, thats why 99% of the stuff you buy comes with
moulded plugs. Anything not fitted with a plug usually has a disclaimer to be fitted by an electrician etc.

Bimetallic strips will cut the power and restore it once things have cooled but the main issue is why did it get so hot and
not blow the fuse.

Myser

chilswelluk said:

Not necessarily, I have top branded MK electrics in my house (sockets, consumer units etc) along with new wiring and have had faulty chargers melting at the plug, which could have been a fire hazard.  At no point did this trip the RCD. That's why a dedicated thermal cut safety plug would be useful.  This would simply monitor the temperature at all points in the plug and then stop conducting if a threshold temperature is reached.

Genuine chargers that have been tested to the appropriate electrical safety standards and have a genuine CE mark are very unlikely to melt, catch fire or disintegrate.  They will use components that will self extinguish if they catch fire and an enclosure that has to meet a certain flammability rating.

Was the charger that you had a clone/cheap one?

Unfortunately, MK accessories aren't the quality they used to be.

a

So you want a bespoke device that cost money to make, to be used on cheap inferior plugs to stop fires, making the plugs more expensive than the ones up to code? You could also just chop the origional plug off and ise a CE plug instead?

Although not exactly what you want, you do get thermal monitors, used in kitchens instead of smoke detectors that are half way towards your pupose

stragglebod

a said:

So you want a bespoke device that cost money to make, to be used on cheap inferior plugs to stop fires, making the plugs more expensive than the ones up to code? You could also just chop the origional plug off and ise a CE plug instead?

Although not exactly what you want, you do get thermal monitors, used in kitchens instead of smoke detectors that are half way towards your pupose

This. The people who are happy to risk electrocution or house fires if it means they can get something cheaper won't pay for such a device, and the people who make sure they buy decent quality stuff from trusted suppliers won't need it.