2amp and 5amp plugs and sockets

[JohnW2]

Especially given that a USB Type-C connector can carry 5A!

Quite so. One only has to look as the size of the components of a 2A plug and socket in comparison with, say, a 0.5 mm² conductor to 'get confused' by the ratings. The only 'unknown' is the quality of contact between the plug's pins and the socket, but (per USB etc.) I find it hard to see that that would limit the safe current to 2A, either!

Kind Regards, John

 

[AdrianUK]

The old round pin plugs & sockets had a relationship between the pins sizes...

The earth pin is a bigger diameter than the L & N pins.

The earth pin of the 2A plug is the same diameter as L & N pins of the 5A plug...
The earth pin of the 5A plug is the same diameter as the L & N pins of the 15A plug....
The earth pin of the 15A plug is the same diameter as the L & N pins of the (very rare) 30A plug.

 

[sparkwright]

I never knew that, but makes good sense from a manufacturing point of view.

Good old fashioned common sense.

We'll all be trying to push the wrong plugs in the wrong sockets now, this would be easy on those small surface sockets that went on skirting boards that John mentioned.

 

[JohnW2]

The earth pin of the 2A plug is the same diameter as L & N pins of the 5A plug...
The earth pin of the 5A plug is the same diameter as the L & N pins of the 15A plug....
The earth pin of the 15A plug is the same diameter as the L & N pins of the (very rare) 30A plug.

Are they the same length, as well as diameter? If they were, that would clearly be a major 'manufacturing advantage', as mentioned by sparkwright.

Kind Regards, John

 

[SimonH2]

However, although in the distant past, some small socket formats ('custom', surface mounted) were available ...

When I got to uni, we had some 2A sockets (surface mount IIRC) in our rooms fed from the lighting circuit - which wasn't metered. Only place to get the plugs was Woollies, or many outgoing students sold them on.
At my parent's last house, it had quite a few sockets where a "double plate" had a single 13A socket, a fuse, and 2off 2A sockets - a very practical way of providing more sockets for lights without filling the wall up.

 

[AndyPRK]

I imagine such plates were sold during the change over from round pin to 13a

 

[FrodoOne]

After reading this thread I realised that the plugs in question were to the BS546 standard and I remembered that South Africa used the 15 A version of this plug/socket outlet combination.

At least, it did.
However, on checking, I found this article https://www.businessinsider.co.za/new-power-plug-electricity-socket-in-south-africa-2018-12

So, from the start of 1918 it has been compulsory in South Africa to install Type N socket outlets, referred to as SANS 164-2.
This article also indicates that wall plates with both SANS 164-1 and SANS 164-2 socket outlets are being installed.

It also states "South Africa’s old three-pronged plug is a killer – here’s how we ended up with a notoriously dangerous electrical system." and https://www.businessinsider.co.za/south-africas-old-three-pronged-plug-is-a-killer-2018-8 has more details.

(The new plug is actually an IEC Type N, although in South Africa it is being called a SANS 164-1)
(Type N plugs and socket outlets are also used in Brazil.)

 

[SUNRAY]

I imagine such plates were sold during the change over from round pin to 13a

I think they were available until fairly recently, say last 10 years. They were very popular for HiFi systems.

 

[SUNRAY]

After reading this thread I realised that the plugs in question were to the BS546 standard and I remembered that South Africa used the 15 A version of this plug/socket outlet combination.

At least, it did.
However, on checking, I found this article https://www.businessinsider.co.za/new-power-plug-electricity-socket-in-south-africa-2018-12

So, from the start of 1918 it has been compulsory in South Africa to install Type N socket outlets, referred to as SANS 164-2.
This article also indicates that wall plates with both SANS 164-1 and SANS 164-2 socket outlets are being installed.

It also states "South Africa’s old three-pronged plug is a killer – here’s how we ended up with a notoriously dangerous electrical system." and https://www.businessinsider.co.za/south-africas-old-three-pronged-plug-is-a-killer-2018-8 has more details.

(The new plug is actually an IEC Type N, although in South Africa it is being called a SANS 164-1)
(Type N plugs and socket outlets are also used in Brazil.)

If they are soooooooo dangerous I'm surprised there are no attempts to stop us using them in their hundred, even thousands, here in the UK

 

[SUNRAY]

Are they the same length, as well as diameter? If they were, that would clearly be a major 'manufacturing advantage', as mentioned by sparkwright.

Kind Regards, John

5A to 15A are.

 

[JohnW2]

5A to 15A are.

Thanks. It therefore sounds as if the pin sizes may well have been determined primarily on the basis of manufacturing convenience/cheapness, rather than primarily electrical considerations, then!

Kind Regards, John

 

[SUNRAY]

Thanks. It therefore sounds as if the pin sizes may well have been determined primarily on the basis of manufacturing convenience/cheapness, rather than primarily electrical considerations, then!

Kind Regards, John

I must admit that I still love the format of the 2-30A plugs and they always feel better than 13A (and a dam site more reliable) I'm truly not surprised in the slightest that 5A & 15A have steadfastly remained the standard within the entertainment environment.
About 2015-5 I found a 15A socket and plug on 7/0.029 & 4mm² flex, BS88 feeding a Strand Junior8 with 8x1KW lamp. According to the paper tag hanging from the T&E the fuse had been uprated to 30A in 1976 and been in regular service since.

Virtually 40years of regular 130% overload without a hint of damage. Compare that to the performance of a 13A socket/plug which struggles to perform properly at 13A.

 

[winston1]

(The new plug is actually an IEC Type N, although in South Africa it is being called a SANS 164-1)
(Type N plugs and socket outlets are also used in Brazil.)

SANS 164-2

Brazil has modified type N so it is not compatible with the standard. They have changed the pin diameter.

 

[securespark]

These plugs have been the standard since the 1950s, and have been blamed for fires and electrocutions. Unlike many other electricity systems across the world, the outlet came with a switch, to turn the plug on and off. This created the false impression of safety, when switched off.

SA’s old plug outlet system had a switch – but this was seen as dangerous because it creates the false impression of safety when it is switched off. In fact, you could still shock yourself if it was switched off.

Well, either the switches were faulty or were connected to the neutral.

 

[AndyPRK]

They said people were working on appliances with it plugged in

And the switch gap wasn’t big.

Also no shutters.