N
Newboy2013
Hi, clearly a new boy with a diversity question to ask. I need to install two new circuits for NAPIT to inspect and am running into a bit of trouble at the chosen site. The issue is one of diversity with two Consumer Units, as firstly there appears to be no guidance on the loading of Distribution Circuits (I have assumed breaker rating value), and secondly before I have even started work things look overloaded with the way that I have worked things out.
The house has two CU's, teh second one installed recently to provide power and lighting to the extension, and is itself fed from a 40A breaker in CU1 via 10mm2 cable.
Simpley doing a calc on info below gets me to a point where with diversity I have a calling for over 120A through a 100A switch. Have I done the calcs right, and would a better solution be to install a Henley block and feed both CU's from this.
[TABLE="width: 655"]
[TR]
[TD]Consumer Unit[/TD]
[TD]Breaker[/TD]
[TD]Rating (A)[/TD]
[TD]Points[/TD]
[TD]Type[/TD]
[TD]Purpose / Notes[/TD]
[TD="align: right"]Diversity (W)[/TD]
[TD="align: right"]Diversity (A)[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 01[/TD]
[TD]6[/TD]
[TD]9[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Up Right[/TD]
[TD="align: right"]900[/TD]
[TD="align: right"]3.9[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 02[/TD]
[TD]6[/TD]
[TD]5[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Down Right[/TD]
[TD="align: right"]500[/TD]
[TD="align: right"]2.2[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 03[/TD]
[TD]6[/TD]
[TD]4[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Up Left[/TD]
[TD="align: right"]400[/TD]
[TD="align: right"]1.7[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 04[/TD]
[TD]6[/TD]
[TD]6[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Down Left[/TD]
[TD="align: right"]600[/TD]
[TD="align: right"]2.6[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 05[/TD]
[TD]6[/TD]
[TD]7[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Utility[/TD]
[TD="align: right"]700[/TD]
[TD="align: right"]3.0[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 06[/TD]
[TD]Blank[/TD]
[TD]0[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 07[/TD]
[TD]20[/TD]
[TD]3[/TD]
[TD]Radial[/TD]
[TD]Power Utility[/TD]
[TD][/TD]
[TD="align: right"]8[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 08[/TD]
[TD]Blank[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 09[/TD]
[TD]30[/TD]
[TD]11[/TD]
[TD]Ring[/TD]
[TD]Power Left[/TD]
[TD][/TD]
[TD="align: right"]30[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 10[/TD]
[TD]30[/TD]
[TD]8[/TD]
[TD]Ring[/TD]
[TD]Power Right[/TD]
[TD][/TD]
[TD="align: right"]12[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 11[/TD]
[TD]40[/TD]
[TD]1[/TD]
[TD]Radial[/TD]
[TD]Distribution Circuit CU 2[/TD]
[TD][/TD]
[TD="align: right"]40.0[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 12[/TD]
[TD]30[/TD]
[TD]1[/TD]
[TD]Radial[/TD]
[TD]Cooker (11.1kW)[/TD]
[TD][/TD]
[TD="align: right"]21.5[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[TD]180[/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD="align: right"]125.0[/TD]
[/TR]
[/TABLE]
[TABLE="width: 655"]
[TR]
[TD]CU2[/TD]
[TD]MCB 01[/TD]
[TD]32[/TD]
[TD]8[/TD]
[TD]Ring[/TD]
[TD]Extension Power[/TD]
[TD][/TD]
[TD="align: right"]32[/TD]
[/TR]
[TR]
[TD]CU2[/TD]
[TD]MCB 02[/TD]
[TD]32[/TD]
[TD]3[/TD]
[TD]Ring[/TD]
[TD]Garage Power[/TD]
[TD][/TD]
[TD="align: right"]12.8[/TD]
[/TR]
[TR]
[TD]CU2[/TD]
[TD]MCB 03[/TD]
[TD]6[/TD]
[TD]9[/TD]
[TD]Radial[/TD]
[TD]Entension Lights Tungsten[/TD]
[TD="align: right"]900[/TD]
[TD="align: right"]3.9[/TD]
[/TR]
[TR]
[TD]CU2[/TD]
[TD]MCB 04[/TD]
[TD]16[/TD]
[TD]1[/TD]
[TD]Radial[/TD]
[TD]Central Heating (112 W)[/TD]
[TD][/TD]
[TD="align: right"]0.0[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD="align: right"]48.7[/TD]
[/TR]
[/TABLE]
The house has two CU's, teh second one installed recently to provide power and lighting to the extension, and is itself fed from a 40A breaker in CU1 via 10mm2 cable.
Simpley doing a calc on info below gets me to a point where with diversity I have a calling for over 120A through a 100A switch. Have I done the calcs right, and would a better solution be to install a Henley block and feed both CU's from this.
[TABLE="width: 655"]
[TR]
[TD]Consumer Unit[/TD]
[TD]Breaker[/TD]
[TD]Rating (A)[/TD]
[TD]Points[/TD]
[TD]Type[/TD]
[TD]Purpose / Notes[/TD]
[TD="align: right"]Diversity (W)[/TD]
[TD="align: right"]Diversity (A)[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 01[/TD]
[TD]6[/TD]
[TD]9[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Up Right[/TD]
[TD="align: right"]900[/TD]
[TD="align: right"]3.9[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 02[/TD]
[TD]6[/TD]
[TD]5[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Down Right[/TD]
[TD="align: right"]500[/TD]
[TD="align: right"]2.2[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 03[/TD]
[TD]6[/TD]
[TD]4[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Up Left[/TD]
[TD="align: right"]400[/TD]
[TD="align: right"]1.7[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 04[/TD]
[TD]6[/TD]
[TD]6[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Down Left[/TD]
[TD="align: right"]600[/TD]
[TD="align: right"]2.6[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 05[/TD]
[TD]6[/TD]
[TD]7[/TD]
[TD]Radial[/TD]
[TD]Tungsten Lights Utility[/TD]
[TD="align: right"]700[/TD]
[TD="align: right"]3.0[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 06[/TD]
[TD]Blank[/TD]
[TD]0[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 07[/TD]
[TD]20[/TD]
[TD]3[/TD]
[TD]Radial[/TD]
[TD]Power Utility[/TD]
[TD][/TD]
[TD="align: right"]8[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 08[/TD]
[TD]Blank[/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[TD][/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 09[/TD]
[TD]30[/TD]
[TD]11[/TD]
[TD]Ring[/TD]
[TD]Power Left[/TD]
[TD][/TD]
[TD="align: right"]30[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 10[/TD]
[TD]30[/TD]
[TD]8[/TD]
[TD]Ring[/TD]
[TD]Power Right[/TD]
[TD][/TD]
[TD="align: right"]12[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 11[/TD]
[TD]40[/TD]
[TD]1[/TD]
[TD]Radial[/TD]
[TD]Distribution Circuit CU 2[/TD]
[TD][/TD]
[TD="align: right"]40.0[/TD]
[/TR]
[TR]
[TD]CU1[/TD]
[TD]MCB 12[/TD]
[TD]30[/TD]
[TD]1[/TD]
[TD]Radial[/TD]
[TD]Cooker (11.1kW)[/TD]
[TD][/TD]
[TD="align: right"]21.5[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[TD]180[/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD="align: right"]125.0[/TD]
[/TR]
[/TABLE]
[TABLE="width: 655"]
[TR]
[TD]CU2[/TD]
[TD]MCB 01[/TD]
[TD]32[/TD]
[TD]8[/TD]
[TD]Ring[/TD]
[TD]Extension Power[/TD]
[TD][/TD]
[TD="align: right"]32[/TD]
[/TR]
[TR]
[TD]CU2[/TD]
[TD]MCB 02[/TD]
[TD]32[/TD]
[TD]3[/TD]
[TD]Ring[/TD]
[TD]Garage Power[/TD]
[TD][/TD]
[TD="align: right"]12.8[/TD]
[/TR]
[TR]
[TD]CU2[/TD]
[TD]MCB 03[/TD]
[TD]6[/TD]
[TD]9[/TD]
[TD]Radial[/TD]
[TD]Entension Lights Tungsten[/TD]
[TD="align: right"]900[/TD]
[TD="align: right"]3.9[/TD]
[/TR]
[TR]
[TD]CU2[/TD]
[TD]MCB 04[/TD]
[TD]16[/TD]
[TD]1[/TD]
[TD]Radial[/TD]
[TD]Central Heating (112 W)[/TD]
[TD][/TD]
[TD="align: right"]0.0[/TD]
[/TR]
[TR]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD] [/TD]
[TD="align: right"]48.7[/TD]
[/TR]
[/TABLE]