10 amp rating on wall socket

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sleemanj

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#615473 26-Apr-2012 14:44

qwerty7:
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

Assuming something else doesn't fry first, yes it would, but that fuse will be supplying more than one socket, so the combined current draw on all the sockets being protected by that fuse could not be over 15amps, or the fuse will blow.

Also consider that the instantaneous startup current draw of some devices (fridges etc) may be quite high, but drop to well under the 10amp range within a few hundred milliseconds - you wouldn't want a 10amp fuse blowing every time your fridge compressor kicked in :)

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James Sleeman
I sell lots of stuff for electronic enthusiasts...

qwerty7

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#615477 26-Apr-2012 15:05

yes your right, of course it would supply more than one socket. (classic case of trying to make things too complicated and forgetting to look at them simply)

Bung

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#615486 26-Apr-2012 15:37

sleemanj:
qwerty7:
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

Assuming something else doesn't fry first, yes it would, but that fuse will be supplying more than one socket, so the combined current draw on all the sockets being protected by that fuse could not be over 15amps, or the fuse will blow.

A heater intended for 10 amp sockets wouldn't be approved if it could draw more than 10 amps.

The fuse or circuit breaker is there to protect the cable.

gregmcc

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#615528 26-Apr-2012 16:33

sleemanj:
qwerty7:
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

Assuming something else doesn't fry first, yes it would, but that fuse will be supplying more than one socket, so the combined current draw on all the sockets being protected by that fuse could not be over 15amps, or the fuse will blow.

Also consider that the instantaneous startup current draw of some devices (fridges etc) may be quite high, but drop to well under the 10amp range within a few hundred milliseconds - you wouldn't want a 10amp fuse blowing every time your fridge compressor kicked in :)

You will find that circuit breakers rating 15 amps (or whatever) it wont trip the moment it reaches 15 amps, there is a time vs. amps constant built in so if it have a very high current drain such as a short circuit there will be an almost instant trip, whereas if you have a slight overcurrent draw then it will several hours before it trips

gzt

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#615556 26-Apr-2012 17:11

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

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

qwerty7: 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: 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: 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.

Almost too hot too touch would definitely indicate a problem at that end. There are three main possibilities for the cause of this kind of fault:

1. A fault within the moulded plug - where a wire joins a plug pin
2. Bad contact between one or more plug pins and the wall socket
3. A fault within the wall socket - worn out socket or bad contact at any terminating point within the socket

Touching the plug pins* after you have unplugged it too see if one is hotter than the others - if one of the pins is insanely hot, then there is bad contact on that pin within the socket or within the moulded plug itself.

If it is bad contact between the plug pins and the socket then bending the plug pins outward slightly can help get good contact - but I'm sure it is not a recommended solution. By the way, this can potentially damage dodgy moulded plugs and cause them to become faulty (#1).

If you get a tradesman out, then replacing the plug and socket at the same time might save you a second visit.

Way back, I did encounter a situation where a tradesman had replaced a wall socket and neglected to tighten the positive/phase terminator. The bad contact between the wire and the terminal generated a surprising amount of heat in the socket and it was only running a TV. That situation would be a rare situation!

Do you have another 2400W heater you can try on that socket to see if the same thing happens at the socket?

[*Edit: Just in case it is not obvious - do not touch the pins in the socket under any circumstances!]

lapimate

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#615583 26-Apr-2012 17:56

Bung: ... 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.

Also NZ domestic wiring connections are generally secured by means of compression screws and over time the copper wire may deform or "creep" under the pressure of the screw thereby causing contact to loosen and contact resistance heating to develop. This may exacerbate the loss of plasticiser from PVC or TPS insulation which results in brittle deterioration of the insulation.

richms

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#615602 26-Apr-2012 18:43

Also goes without saying that buying off brand junk outlets is just going to make it worse. As is using junk extension cords and powerstrips.

Richard rich.ms

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