That socket is intended for the middle eastern market. Saudi Arabian Standards Organization (SASO) issues SSA numbers.
These outlets are used alongside UK style BS1363 which also have an SSA code. MK makes both of them on UK-type plates so they can be installed easily. American plates and boxes would be very problematic.
127V 50Hz is used in quite a few Middle Eastern and caribbean countries. It's an oboselete European standard that was used in a very similar way to 120V in the US.
i.e. circuits were either 127V + 0
or 127+127 giving you a potential difference of around 220V between the two terminals but 127V between either terminal and ground.
However it's survived in places outside the EU but as far as I'm aware is being phased out as it is rather difficult to get 127V 50hz appliences. US appliences designed to be used on 50/60Hz work "ok-ish" on 127V but it's pushing the upper limit a bit particularly if there's any kind of a voltage spike. There are a lot of stories of US appliences plugged into outlets that seemed to be US standard being wiped out.
In most instances you'll find 127V is used almost exclusively for lighting with 220V used for almost everything else.
However, most countries that use 50Hz are converging on Cenelec (european) standards and adopting 230V L + 0V N for single phase and 400V for 3-phase.
Interestingly, MK has a very large presence in many places that would have had a lot of contact with the UK / former british colonies.
So you'll find MK plugs, sockets, systems and distribution / manufacturing businesses in places like India, HK / China and various Middle Eastern and african countries.
Also, I think MK's version of a NEMA outlet is actually pretty good. Shutters sould be a nice addition!
[This message has been edited by djk (edited 12-28-2003).]
