Why are mains plug pins usually made of brass in the UK?

[seanspotatobusiness]

Why are mains plug pins usually made of brass in the UK? They're usually a silver-coloured metal in other countries, right?

 

[Minder]

Not sure the reason, but one thing struck me as odd, being an electrician in the UK I came across quit a few outlets where the plug had overheated, this in spite of the large contact area and the lower current for a given load than a 120v system.
When coming to Canada and observing the smaller plug and and higher currents for the given load, it surprised me that there did not seem to be the overheating condition seen in UK.??
M.

 

[seanspotatobusiness]

Not sure the reason, but one thing struck me as odd, being an electrician in the UK I came across quit a few outlets where the plug had overheated, this in spite of the large contact area and the lower current for a given load than a 120v system.
When coming to Canada and observing the smaller plug and and higher currents for the given load, it surprised me that there did not seem to be the overheating condition seen in UK.??
M.

Someone told me that brass has eight times higher resistivity than copper. Do plugs elsewhere use plated copper?

 

[Arouse1973]

I think it's due to robustness. Brass is harder wearing than copper. Aluminium produces a greater oxide layer and gold is way too expensive
Adam

 

[Minder]

Many of the plugs here are just plain brass, some plated brass, I think it has to do a lot with the better contact area with N.A. plugs.
Also I did observe the UK plug pins were rough rather than smooth finish, at least back then.
M.

 

[duke37]

Zinc is cheaper than tin so brass is cheaper than bronze.
Brass with a little lead will machine easily.
Copper is too soft unless alloyed with toxic beryllium.

The overheating of the UK plugs is often due to poor connections to the inbuilt fuse. At one time I worked for an electrical company which made plugs to power stations. We were not allowed to take more than 8A from a 13A plug

 

[Minder]

That's possible, In N.A. there is no fusing in the plug and pin area is smaller.
M.

 

[Bluejets]

I think most is a compromise between cost, manufacturing and wear and tear.

No mention was made of the difference in materials in the actual sockets between the UK and US so perhaps the answer why the UK ones seem to burn out.

Usually burn out plug/ sockets here in Aus are due to old worn out usually in kitchens or laundries where large current devices reside.

Actually it is a wonder there are not more failures. I have seen double adaptors "ganged" together in a fashion where, because there were so many, 6 I think, they kept falling out. So the fix of the householder was to insert a cup hook above and tie some string around the complete assembly.
A bit like some of those now-a-day six pack sockets with loading that sends shivers up the spine.
Yes, maybe some do have an included o/l but the plug usually burns out before the o/l trips.

The silver finish is just a metal coating on the brass pins. Most in Aus appear this way although the older ones from 20 years ago did not have any coating. Commercial 3 phase plug/sockets are still uncoated.

Anyhow, found this reference....might help ....
http://www-materials.eng.cam.ac.uk/mpsite/plug/non_IE/page4.html