OK i might end up feeling silly after this one - Points of Utilisation?

[Robinson]

Just trying to work out my Max demands and diversities for a job and assessment, just want make sure all firm in my mind. However question is. (all be it may a stupid one)

Diversity OSG Tab1B. No. 10. S/O - 100% of current demand of largest point of utilisation + 40% of current demand of every other point of utilisation.

Would be correct in assuming that a double socket would have 2 points of utilisation?

Hope this not too much of a dafty.

 

[telectrix]

IMO a double socket outlet is 1 point of utilisation. although it has 2 outlets. it is 1 wired point.

 

[Robinson]

Hmmm ok interesting. Is there anywhere i can get in the big red book you know of i could get a confirmation on that. be looking to no avail.

 

[Robinson]

that didnt make much sense. ya get me though

 

[Des 56]

16th edition On site guide page 156 "recomended provision of sockets
Number of sockets in dining room = 3
All sockets are twin

If you counted a twin as 2 points, then the guidance is telling yoiu to use one and a half twin sockets, which is nonesense


Single socket is one twin socket is oine,tripple socket is one point of utilisation

 

[ringer]

@Telectrix - a double socket may be considered as a single point for costing/pricing purposes or for spurs etc, but for diversity calcs, that 'point' is capable of consuming 26A. However.....

@James - OSG p96 Table 1A - for 13A socket outlets, read Notes:1 which refers you to Appendix 8
Also, read p95 which gives you two alternatives to the standard 100%+40% calculation. According to these paras the OSG says you, as the designer, can use your own system for calculating diversity. If you quote these paras to your assessor, make sure you can back up your decisions with reasonable logic and assumptions.
Appendix 8 gives you a design for a circuit of 13A S/O based on floor area rather than number of outlets, but do bear in mind the paras on p158 about reasonable sharing of the load re washing machines, dishwashers etc

 

[Robinson]

As this is for calculations i do want to be able to back it up. as you said ringer and i thought that point is capable of consuming 26amps.
The circuit in question is this then a Radial 2.5mm - 3 double sockets. (2 low level in dining area of a kitchen/dining open plan and 1 at work surface height above some units in same dining area) also a switch fuse spur for very small 15" max LCD TV and a Spur for a overhead extract 5amp jobby.
I was at the point of trying to assess if this is all too much for a radial. 20 m cable run, clip direct. There basically seperate radials for each appliance in Kitchen and a ring for the actual kitchen (above unit sockets).
So all these sockets in question would be used for really would be poss lamp stands/table lamp...also Maybe a kettle(max load) on the one above unit. so i wanted to get the total demand with diversity etc etc....as was bit concerned

kinda lost the plot now heheheh

 

[chronyx]

Hi guys, found this through Google! To save starting another thread, I will bump this as I'm just curious to see how experienced sparks interpret the 'regs' :confused5:

I have a double socket on a 4mm radial, right near the C.U.

Would this count as 13A, 19.5A, or 26A? (Business/Commercial so 100%+ 50% under standard arrangement.) Just not sure as it is possible to plug in 2x 13A loads!

 

[ackbarthestar]

Maximum demand is usually applied to sub-main cables supplying the circuits fed from distribution boards not individual points of utilization unless of course its a radial feeding one item of equipment such as a cooker.
example: for ring final circuits: 1st circuit = 100%, 2nd circuit = 40% domestic (50% commercial), 3rd circuit = 40 or %50 etc

A point of utilization with regards to skt outlets can either be 1 single or 1 double. In either case both are usually supplied using a 2.5 or 4.0mm2 cable and will be protected by fuses of a maximum combined value which will be no greater than 26A maximum.

 

[Engineer54]

Just trying to work out my Max demands and diversities for a job and assessment, just want make sure all firm in my mind. However question is. (all be it may a stupid one)

Diversity OSG Tab1B. No. 10. S/O - 100% of current demand of largest point of utilisation + 40% of current demand of every other point of utilisation.

Would be correct in assuming that a double socket would have 2 points of utilisation?

Hope this not too much of a dafty.

This is something you should really know, if your out there installing circuits in clients homes and offices...

 

[chronyx]

Thanks ackbar :icon7: