Not sure why 6mm² is relevant, so -
may I suggest the use of sockets and installation methods which do allow fitting the circuits required.
Please can someone tell me, is comparing 4mm and 2.5mm cable the same as comparing a chainsaw and a blender?
- Thread starter PotatoSoup
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- 2.5mm v 4mm fire hazard shock
may I suggest the use of sockets and installation methods which do allow fitting the circuits required.
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Pretty obviously the rating which they can safely carry.
That may well be the i tended meaning, but I would not regard it as particularly 'obvious'. The current which a plug/socket can safely carry cannot dictate what might be connected to the plug.
Maybe it is the case that 'portable' ('plug-in') appliances and equipment which draw more than 10A are 'not allowed' in Australia?
Kind Regards, John
It's more a case that an appliance that could draw more current, should have the correct plug...
AS/NZS 3112 - Wikipedia
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Many thanks. That's very interesting and definitely something of which I was not aware - and is a far more useful answer to my question than Risteard's suggestion that the the answer was "obvious".
What I'm less clear about is the 'point' of having all those variants of sockets. If one assumes 20A circuits, what is the difference between the 10A, 15A and 20A sockets that could be connected to it, other than that they will only accept a plug of the same or lower 'rating'? Are the 15A ones really not able to 'safely carry' 15A or 20A, or the 15A ones not able to 'safely carry'; 20A?
In other words, at first sight it would seem (to me) that it would be simpler and more flexible/versatile for all sockets on 20A circuits to be 20A ones. What am I missing?
Kind Regards, John
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An interesting system, however it seems looking at it that the 10 amp plug will fit all, so I assume fused? I was actually wondering if there is a blender attachment for my chainsaw, it has a leaf blower and hedge cutting attachment so suppose possible!
I know there was some thing about maximum motor sizes for vacuum cleaners, but if also a leaf blower it seems it does not count, so I have a 3 kW vacuum cleaner.
Be it blender v chain saw, or ring v radial there are many pros and cons, with the former we are really looking at use in the house, so the petrol version is not really to be considered, and with the latter we are looking at the 13 amp British socket, and the main limitation is what cables will fit in the sockets, specially is special sockets, be it filtered, USB, RCD, or wifi are used, we want to be able to select a socket appropriate for the area and use it without having to have deep back boxes with connectors in them to connect up over sized cables.
So simple, the 13 amp socket was designed to be used with the British ring final, there will of course be exceptions, but in the main best if used with a ring final which they were designed to be used with.
I will admit I was a little worried about installing a system which when some one did an EICR showed it did not comply with volt drop requirements, but after making the program so I could easy work out volt drop from the loop impedance, I realised hard to prove it was out of spec unless well out, as the loop impedance tester is not that accurate.
In 1954 my parents bought their house, and it was 2022 before I realised the wall lights had never complied with regulations, and by then the builder was long gone, and house had already been rewired. So even if many radials don't comply, unlikely anyone will need to correct them.
I know there was some thing about maximum motor sizes for vacuum cleaners, but if also a leaf blower it seems it does not count, so I have a 3 kW vacuum cleaner.
Be it blender v chain saw, or ring v radial there are many pros and cons, with the former we are really looking at use in the house, so the petrol version is not really to be considered, and with the latter we are looking at the 13 amp British socket, and the main limitation is what cables will fit in the sockets, specially is special sockets, be it filtered, USB, RCD, or wifi are used, we want to be able to select a socket appropriate for the area and use it without having to have deep back boxes with connectors in them to connect up over sized cables.
So simple, the 13 amp socket was designed to be used with the British ring final, there will of course be exceptions, but in the main best if used with a ring final which they were designed to be used with.
I will admit I was a little worried about installing a system which when some one did an EICR showed it did not comply with volt drop requirements, but after making the program so I could easy work out volt drop from the loop impedance, I realised hard to prove it was out of spec unless well out, as the loop impedance tester is not that accurate.
In 1954 my parents bought their house, and it was 2022 before I realised the wall lights had never complied with regulations, and by then the builder was long gone, and house had already been rewired. So even if many radials don't comply, unlikely anyone will need to correct them.
The !0 A, 15 A and 20 A socket-outlets shown are connected to circuits rated at 20 A (2.5 mm²).
25 A and 32 A socket-outlets are supplied by circuits of those higher ratings
The "higher rated" socket-outlets are for use with devices with a higher current "draw".
Window mounted Air-Conditioners often required more than 10 A, so 15 A socket-outlets were required.
("Installed" (hard wired) Air-Conditioners are now much more common.)
Surface mounted 10 socket-outlets (https://commons.wikimedia.org/wiki/File:Australian_Surface_Socket-Outlet_and_Plug.jpg ), used largely for "luminaires" and "ceiling-fans", are usually installed on 10 A (1.5 mm²) "Lighting Circuits".
(Hence, there should be no problems of which any "Winston" could complain !)
While these higher rated socket-outlets exist, I doubt if 99% of the Australian population will ever have seen any above 15 A in use (I have not)
The 15 A Plug and Socket-outlet is used at Caravan Parks.
Higher rated socket-outlets tend to be "Industrial" and "Round-Pin" socket-outlets are usually used above 15 A.
If you view (or scan) https://www.cool386.com/plug/plug.html you will see that the Australian (10 A) plug was developed in the 1930s.
At the time, there were (by one count) around 70 different types of (two and three pin) British and US plugs and socket-outlets (of various "ratings") in use in Australia !
In the above it is remarked :- "While electrical safety wasn't given the attention that gets these days, it was realised that earthing of appliances was a necessity, and thus three pins were required."
This is summarised in https://en.wikipedia.org/wiki/AS/NZS_3112
"Australia's standard plug/socket system was originally codified as standard C112 (floated provisionally in 1937, and adopted as a formal standard in 1938).
The Australian standard of 1937 was the result of a "gentlemen's agreement", reportedly from 1930, between manufacturers Fred Cook of Ring-Grip, Geoffrey Gerard of Gerard Industries and Brian Harper Miller of the State Electricity Commission of Victoria (SECV).
The design was based on an American plug and socket-outlet first intended for use at 120 V which was patented in 1916 under U.S. Patent 1,179,728 by Harvey Hubbell."
"One of the reasons behind the adoption of that particular design was that it was cheap to make, with the flat pins being able to be easily stamped out of sheet brass, in contrast to round pins or thicker rectangular ones used in other countries."
The American plug and socket were "rated" at 15 A 120 V (1800 W maximum) - and, I suspect that the patent may have "lapsed" !
Considering that Australia used 240 V, rating these at 10 A 240 V gave 2400 W maximum - which was probably considered (more than) enough for domestic appliances, at the time.
It is my understanding that Australian "wiring practices" of the time were closely aligned to those of pre-war UK.
Certainly, after WWII "Power" wiring in Australian homes was usually "Imperial" 7/029, which is the equivalent of 2.5 mm² today.
Using Fuses, this wiring was "rated" at 16 A but became "rated" at 20 A when using quicker acting Circuit Breakers.
Similarly, "Lighting Circuits" (3/029) were rated at 8 A but became "rated" at 10 A when using Circuit Breakers.
25 A and 32 A socket-outlets are supplied by circuits of those higher ratings
The "higher rated" socket-outlets are for use with devices with a higher current "draw".
Window mounted Air-Conditioners often required more than 10 A, so 15 A socket-outlets were required.
("Installed" (hard wired) Air-Conditioners are now much more common.)
Surface mounted 10 socket-outlets (https://commons.wikimedia.org/wiki/File:Australian_Surface_Socket-Outlet_and_Plug.jpg ), used largely for "luminaires" and "ceiling-fans", are usually installed on 10 A (1.5 mm²) "Lighting Circuits".
(Hence, there should be no problems of which any "Winston" could complain !)
While these higher rated socket-outlets exist, I doubt if 99% of the Australian population will ever have seen any above 15 A in use (I have not)
The 15 A Plug and Socket-outlet is used at Caravan Parks.
Higher rated socket-outlets tend to be "Industrial" and "Round-Pin" socket-outlets are usually used above 15 A.
Since you have raised this question, the answer may be one of "chicken and egg" or of "evolution" of standards and practices.
If you view (or scan) https://www.cool386.com/plug/plug.html you will see that the Australian (10 A) plug was developed in the 1930s.
At the time, there were (by one count) around 70 different types of (two and three pin) British and US plugs and socket-outlets (of various "ratings") in use in Australia !
In the above it is remarked :- "While electrical safety wasn't given the attention that gets these days, it was realised that earthing of appliances was a necessity, and thus three pins were required."
This is summarised in https://en.wikipedia.org/wiki/AS/NZS_3112
"Australia's standard plug/socket system was originally codified as standard C112 (floated provisionally in 1937, and adopted as a formal standard in 1938).
The Australian standard of 1937 was the result of a "gentlemen's agreement", reportedly from 1930, between manufacturers Fred Cook of Ring-Grip, Geoffrey Gerard of Gerard Industries and Brian Harper Miller of the State Electricity Commission of Victoria (SECV).
The design was based on an American plug and socket-outlet first intended for use at 120 V which was patented in 1916 under U.S. Patent 1,179,728 by Harvey Hubbell."
"One of the reasons behind the adoption of that particular design was that it was cheap to make, with the flat pins being able to be easily stamped out of sheet brass, in contrast to round pins or thicker rectangular ones used in other countries."
The American plug and socket were "rated" at 15 A 120 V (1800 W maximum) - and, I suspect that the patent may have "lapsed" !
Considering that Australia used 240 V, rating these at 10 A 240 V gave 2400 W maximum - which was probably considered (more than) enough for domestic appliances, at the time.
It is my understanding that Australian "wiring practices" of the time were closely aligned to those of pre-war UK.
Certainly, after WWII "Power" wiring in Australian homes was usually "Imperial" 7/029, which is the equivalent of 2.5 mm² today.
Using Fuses, this wiring was "rated" at 16 A but became "rated" at 20 A when using quicker acting Circuit Breakers.
Similarly, "Lighting Circuits" (3/029) were rated at 8 A but became "rated" at 10 A when using Circuit Breakers.
I must say that I mentally assumed the opposite. We were told explicitly that the 10A 'outlet' was unfused, so I was thinking (rightly or wrongly) that the same applied to the corresponding 10A plug.
I'm not sure what that has to do with this discussion
That is probably historically true. However, the fact that the corresponding 13A plugs are fused is as relevant to radials (particularly 32A ones) as to ring finals. Even with 20A radials, in the absence of a fused plug one would theoretically have to have a 2.5 mm² flex for appliances, and with a 32A radial, one would theoretically need 4.0 mm² flex - which would be ridiculous/impractical, particular for small appliances.
That ought to be an unnecessary worry, since there are effectively no 'requirements' in BS7671 regarding voltage drop, and an EICR is not meant to 'code' (at least, not above C3) something that is not 'required' by BS7671, even if recommended in guidelines.
Kind Regards, John
That's interesting.
The same could have happened in the UK; up-rating the ring circuit to 40A instead of just 32A. Although possible, this probably was not required.
Alternatively, the cable used could have been reduced to 1.5mm² in line with the regulation (method C, of course).
This would then make arguments between rings and radials more conclusive.
Similarly.
Thanks for explaining and clarifying the situation.
That makes the situation much simpler (for most people) than I had feared. In fact, it's really very similar to the 'pre-WWII' situation in the UK (which persisted in many homes, including my parents', until the 1970s or beyond) when we had 5A and 15A sockets, protected and used in much the same ways as you describe for the present situation in Australia.
Kind Regards, John
No.
However, all "Power Boards" sold in Australia must be equipped with a 10 A "Overload Cutout" (Circuit Breaker).
These are always "re-settable".
File:Four way power board Australian plugs.jpg - Wikimedia Commons
As I wrote to eric, that is what I had assumed from what you wrote.
Although not necessary, the equivalent things in the UK have been known to contain 13A fuses. However, as said, that is not necessary, since the plug supplying them will contain a fuse, which cannot be greater than 13A.
However, that does not relate to the implied point being made by eric about a single 'socket outlet' - that if a '10A plug' is plugged into a '10A outlet' (both plug and socket being unfused) on a 20A circuit, there is presumably no way of being sure that the plug will not be connected to a load drawing more than 10A, maybe even 20A?
Kind Regards, John
True.
However, no "commercial" product sold in Australia drawing more than 10 A would be fitted with a 10 A plug.
Any such "commercial" product would come fitted with a 15 A plug (or, perhaps, a 20 A plug, in the case of an Oven.)
Replacing such a plug with a 10 A plug would be "contrary to regulations".
Of course, the "wiring of the premises" would not be overloaded by any single device in such cases - and
there is really no "current carrying differences" between 10 A, 15 A and 20 A Socket outlets - except that 20 A Socket-Outlets are not available as "doubles" while 15 A Socket-Outlets are !!
(https://directwholesale.com.au/prod...-250v-15amp-horizontal-twin-powerpoint-white/ )
The "capacity" of the flexible "cord" used is probably more significant.
Having written the above, I must "report" that (over 8 years ago), my Daughter brought back from the UK a "Thermomix", which she wanted to use here in her Kitchen, and asked me to replace the UK plug with an Australian plug.
Looking at the, name-plate, I noted that the (nominal) maximum current "drawn" by this UK/European 230/240 V device was just over 10 A !!!
I had the choice of
replacing a pair of 10 A socket-outlets in her Kitchen with 15 A socket-outlets and using a 15 A plug (at some cost - and inconvenience in obtaining the "parts")
or
just using an easily available 10 A plug, which (sometimes) might be slightly "overloaded".
(Guess what I did ?)
Also true, but any practices rely on people not doing things which are "contrary to regulations" obviously leaves some uncertainties.
That's what I suspected, and the reason I asked what was the difference (other than pin sizes) between 10A and 20A outlets. As you go on to say ..
... that would be the issue in the UK. Per UK regs, a flexible cable protected only by a 20A MCB would have to be at least 2.5mm² - which would be a bit ridiculous for a load which, say, drew only a fraction of 1A (as is true of many 'electronic' loads). With a BS1363 plug, it could be fitted with a 3A fuse (or even a 1A one!), in which case one could use 0.5 mm² flexible cable.
What are the Australian requirements as regard flexible cable sizing in such situations?
It's obviously something we don't (or shouldn't) talk about too much in a forum like this, but there clearly are some situations in which it is 'not unreasonable' to resort to common sense, rather than feeling obliged to adhere strictly to every word of regulations !
Kind Regards, John
That's not strictly - or actually - true, is it?
If the load cannot draw more than the CCC of the flex, then, as with most appliances in the home, the fuse in the plug isn't really necessary.
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