Amount of sockets on a ring

[markharris]

Osg says that a socket circuit's diversity is calculated as 100% of maximum point of utilization,then 40% of remaining points. To me that means the max sockets you can have for a 32a ring would be only be 4 sockets!!!!!
Obviously I am interpreting this info the wrong way, but can anybody explain the rules governing how many sockets you can put on a 32a ring for example?

 

[High Tower]

your looking at diversity calcs,

Sockets allowed on a ring final circuit is unlimited, as long as the floor area does not exceed 100Msq backed by a 32a mcb.

 

[markharris]

Ok, but would having six four way extension leads plugged into 3 double sockets so 12
Appliances (computers/printers/Internet hubs) cause a 32a mcb to trip on a 32a ring?

 

[High Tower]

quite possibly, is there a RCD, as all that crap would take out a RCD, that amount of adaptors is a bad idea from the start!

 

[markharris]

Sorry to be a pain, but why would it trip the rcd, do too many extension leads generate a fault current?

 

[High Tower]

No mate, all IT equipment works on earth leakage, most pc's work on around 3.5mA earth leakage, so put more than about 8 items on any RCD rated at 30mA it will trip, dont forget its not just one circuit on a RCD but many, so even if your little array of extension leads dont eport 30mA add it to other circuits and it may well!

 

[markharris]

Thanks high tower, so I guess you still have to assess the amount of equipment with the amount of sockets that you will have when designing your circuits, even though it will fall within the 100m floor surface area,and not just have an unlimited amount.

 

[High Tower]

If your designing circuits that carry large amounts of IT equipment you then get into the position of splitting circuits into smaller circuits, with RCBO's and high integrity earthing.

 

[High Tower]

Theres still no limit anywhere in 7671 regarding number of sockets

 

[topquark]

No limit on number of sockets, just a limit on the voltage drop (and hence the overall length of the ring).

 

[SirKit Breaker]

Ok, but would having six four way extension leads plugged into 3 double sockets so 12
Appliances (computers/printers/Internet hubs) cause a 32a mcb to trip on a 32a ring?

Do the maths. Add up the loads, and divide it by 230, if it is less than the rated capacity of the protective device then you are fine. As stated excessive use of extension leads is not good, but at least make sure they have a 13a fuse fitted so as not to overload the point in the ring where it is connected. And i also agree with the comments regarding RCD tripping.

Cheers......Howard