this is a cable that is connected to a ring to supply electrical energy to one or more socket.
Spur
spur
A spur outlet is a circuit that does not have a secondary path and is not part of the main ring. Spur sockets can have one cable connected to earth, live, and neutral.
junction box
Extensions to a ring-main are made by running a spur from the nearest socket.
As posted, the question doesn't make much sense - do you mean spur sockets, rather than plugs? Either way, it will depend on local regulations. In the UK, you can fit one socket on a spur from a socket on a ring main.
spur evolves from spurious terminology.In electrical terminology it is denoted by a range of frequency through which any electrical circuit (specaially in case of RF and microwave circuits) is operated.
A spur is an extension connected from some point along the main circuit of an electrical installation. Spurs are sometimes called 'tees'.
A ring around wires in a wiring diagram most often represents a ring circuit in the wiring. A ring circuit is a wiring technique commonly seen in devices from the United Kingdom.
The Diamond Spur Rodeo was held annually in Spokane, WA. It was part of a circuit of rodeos in the Pacific Northwest including Ellensburg Roundup, Omak Stampede and the Pendelton Roundup.
Answer for UK, Europe and countries running a 50 Hz supply service.A ring circuit has two routes to each outlet, a radial has only one.
If you are talking about an electrical ring main it can be as long as you want it as long as it returns back to the circuit breaker with the other end of the cable, which if you didn't return the 2nd end of the cable to the circuit breaker you would have a radial circuit.