MCB sizing

[Jako13!]

Is there any issues in having 10amp breaker if the circuit is pulling just under 6 amps? I know the breakers there to protect the cable and the cable is 2.5 3 core armour. Just curious.

 

[Taylortwocities]

You have answered your own question. For 2.5mm SWA you could have an MCB of up to 25amps. If you need to limit the current at the delivery end of the SWA - maybe because there’s lights there using smaller wiring, or because the instructions state a fuse is needed - then fit an FCU with an appropriately lower rated fuse.

 

[Wilko]

If you know the load is 6A then with 2.5mm conductors the 10 MCB may be a reasonable choice .

 

[Dustydazzler]

Day one of electrical skool

cable bigger than device , device bigger than load

 

[Lucien Nunes]

Otherwise written Iz>=In>=Ib or Ib<=In<=Iz

 

[Zerax]

Or could be... Iz≥In≥Ib or Ib≤In≤Iz

(just showing off as I've just discovered how to do those symbols)
(still working on how to do subscript on here)

 

[radiohead]

Fixed loads do not necessarily require overload protection, as long as fault current protection is met by the device a device rating may exceed the CCC of the cable and still be compliant.

 

[telectrix]

Or could be... Iz≥In≥Ib or Ib≤In≤Iz

(just showing off as I've just discovered how to do those symbols)
(still working on how to do subscript on here)

show us how. us plebs can only do the < and >. and i can sometimes enter "a" without activating the caps lock.

 

[Taylortwocities]

show us how. us plebs can only do the < and >. and i can sometimes enter "a" without activating the caps lock.

Yes, and put a couple if smiley emoticons on thd post as well!

 

[Jako13!]

So when is over load protection needed? In theory you could run a lighting circuit of a 16amp breaker then as long as the cable is correct for 16 amps?