10 amp rating on wall socket

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qwerty7

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#101176 25-Apr-2012 21:37

I notice that the wall sockets have 10 amp stamped on them in small print

I have a BIG HUNGRY oil fin heater rated at something like 2400W

The fuses in the fuse box are 15 amp

When the heater is on full the plug and cord can get quite warm

Should I be worried ?

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#615176 25-Apr-2012 21:52

Do you have the heater plugged straight into the wall socket? or is it going through something else first?

qwerty7

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#615186 25-Apr-2012 22:06

straight into the wall socket, nothing else plugged into the same socket

StarBlazer

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#615205 25-Apr-2012 22:37

Good question. I have a couple of heaters that do the same and they are lower than 2400W.

I gues 2400W on a 240V system it is just about at the peak of 10A (V=I/R). That said the voltage here is not quite 240V - I'm sure it was around 230V last time I checked which means the maths doesn't quite add up. It's been a while since I had to think about this stuff - If I'm correct, a 2.4KW heater will be pulling more than 10amps. Perhaps someone could correct me on this.

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larknz

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#615206 25-Apr-2012 22:37

A 2400w heater draws 10 amps, so there is no problem with the rating of the socket. A flex or plug running at full load will normally get warm. It's only when things get very hot that you may have problems. You are allowed to have 2 sockets connected to a circuit controlled by a 15 amp fuse. That's why the fuse is rated higher than the socket rating.

larknz

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#615207 25-Apr-2012 22:40

A 2400 watt heater draws 10 amps when the voltage is 240 volts. If the voltage is lower then the current will be lower.

illicit

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#615212 25-Apr-2012 23:12

Watts = volts x amps

So, if the voltage decreases, the current rises. Otherwise it wouldn't be 2400 watts.

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larknz

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#615219 25-Apr-2012 23:32

The element has a fixed resistance. The output wattage of the element is not fixed but is dependent on the voltage.
watts = volts squared divided by resistance.
Therefore if volts drop the wattage drops.

gzt

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#615225 25-Apr-2012 23:48

qwerty7: When the heater is on full the plug and cord can get quite warm
Should I be worried ?

If you unplug it, is any pin on the plug too hot to touch or way way hotter than the others at any point?

richms

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#615230 26-Apr-2012 00:35

1mm wire will get warm with 10 amps going thri it. Thats why lighting circuits have to be in 1.5mm cable if you are putting them in insulation inorder to get a 10a breaker. the older 1mm cable should only be on a 6amp one unless it is in free air.

There is all sorts of derating equations that sparkys are supposed to do on installs, but seldom actually bother doing.

Outside the wall, 1mm cable is good for 10 amps for short distances, anything up near 20m then the extension cable should be 1.5mm.

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#615280 26-Apr-2012 09:05

My "2400W" heater only actually uses 1900W, according to my cheapy power meter.

My electrician told me that you can only put 20A through the type of cable I have, so I have to put a new breaker in my switchboard to get more power down the back of my house.

dolsen

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#615291 26-Apr-2012 09:32

From what I've seen, the phase and netural conectors on 15 amp plugs are the same size as those on 10A plugs, only the earth pin is wider (to prevent them being plugged into a 10A socket). I would expect that the manafacturer of the 2400W heater to have used a cable that can carry the approprate load.
Of course, if it gets really warm, then there might be an issue.

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gzt

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#615303 26-Apr-2012 09:53

dolsen: <snip> I would expect that the manafacturer of the 2400W heater to have used a cable that can carry the approprate load. Of course, if it gets really warm, then there might be an issue.

The reality is that manufacturers use OEM plug/cable sets which are marked as meeting a specified standard.

I wonder what the expected life of equipment is under the current standard, and the corresponding life of a plug/cable set at maximum load.

I have needed to replace severely degraded moulded plugs on older 2400W heaters and tumble driers.

qwerty7

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#615344 26-Apr-2012 11:54

gzt:
qwerty7: When the heater is on full the plug and cord can get quite warm
Should I be worried ?

If you unplug it, is any pin on the plug too hot to touch or way way hotter than the others at any point?

I don't think i have ever touched the pins after i have unplugged it. What are you suggesting? (so i know what to look for)

qwerty7

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#615347 26-Apr-2012 11:58

richms: 1mm wire will get warm with 10 amps going thri it. Thats why lighting circuits have to be in 1.5mm cable if you are putting them in insulation inorder to get a 10a breaker. the older 1mm cable should only be on a 6amp one unless it is in free air.

There is all sorts of derating equations that sparkys are supposed to do on installs, but seldom actually bother doing.

Outside the wall, 1mm cable is good for 10 amps for short distances, anything up near 20m then the extension cable should be 1.5mm.

interesting info thanks

maybe i need to refresh my electrical knowledge i was thinking the fact the fuse was 15amps would allow the heater to draw 15 amps through the 10 amp socket

i remember at least once the plug was almost too hot to touch and the wall felt warm above the socket. Don't freak out I hate dodgy electrics, but something doesn't seem right

Bung

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#615379 26-Apr-2012 12:25

qwerty7: i remember at least once the plug was almost too hot to touch and the wall felt warm above the socket. Don't freak out I hate dodgy electrics, but something doesn't seem right

If there's no resistance there won't be any heat. Dirty or loose contacts in the socket can be an issue especially when the socket is used for the vacuum plug that often gets dragged out sideways.

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