Outdoor and indoor lighting on same circuit

[Ellsa100]

Hi

The ground floor of my house has two lighting circuits which are each protected by an MCB. One of those circuits is just indoor lights. The other circuit covers both indoor and outdoor lights. There is no RCD protection for either of these circuits.

The problem with the circuit that covers both indoor and outdoor lights is that outdoor lights occasionally have issues with water ingress etc which will cause the MCB to trip, but this then trips for the indoor lights on the same circuit too. Not good.

QUESTION 1 - Is it easy for an electrician to effectively separate the circuit which currently has both an indoor and the outdoor circuit on one MCB so that the outdoor circuit is on its own independent MCB and the indoor circuit is on its own independent circuit? By easy I mean something this is not an extensive rewire job etc.

I’m guessing that the house - built in 2006 - originally probably split the ground floor lighting circuits into two circuits, each protected by a 6A MCB, because of the higher power rating of halogen bulbs - say 50W - whereas now all the bulbs are LED.

QUESTION 2 - can the two indoor circuits be combined into one circuit protected by a single 6A MCB given a typical LED consumes roughly a tenth of the power of halogens?

-> the reason I ask this is I’d rather have the whole ground floor indoor lights on one MCB and the outdoor lights on another MCB (than have two ground flood light circuits each occupying an MCB together with an MCB for the outdoor lights)

QUESTION 3 - presumably I should use MCB+RCDs or RCBOs for both indoor and outdoor lighting circuits (rather than just an MCB)?

Thank you!

 

[PeakSteve]

But the circuit doe snot have RCB protection...I thought a MCB would not trip from simply a live to earth fault - wouldn't you need an RCB or RCBO? thanks

It depends on the type of Earth, but as long as >6A fault current can flow from L to E, it can still trip an MCB!
But as stated above, it is likely to be more than simply damp (which would trip an RCD @ 30mA, but likely wouldn't run to anything like enough to trip an MCB)