Consumer Unit Load

[ianphilip007]

hello guys

i have a query if you have a C.U. with a 63A main switch fed from a 60Amp main fuse, does the total value of Mcb's fitted have to be below 60Amps before diversity? or is it that as long as the max demand is below the 60Amps ? I have always thought as long as the max demand figure was below the C.U. rating that was ok. just read a note in the OSG about the C.U. having to be able to take total load current applied with no diversity which totally confused me anyone make sense of that ?

 

[Bozza]

Total load not to exceed main switch rating. All your mcb's added together will exceed the main switch rating but, how often do you have all your mcb's pulling the maximum current rating.

 

[Bradzz]

Just somthing in one of my books

 

[ianphilip007]

think ive just been totally stupid lol just re read the note from the OSG. i assume it means no diversity applied to the rating of the mainswitch itself, and not as i thought diversity applied to the individual circuits. that makes sense now lol unless im wrong

 

[Bozza]

Apart from a shower circuit. (no diversity allowed)

 

[kamkam]

Pages 96-97 of OSG Tables 1A &1B its all there.