Discuss 2 Lighting Circuits on one 6A CB in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

N

NewbieRuffy

Hi All, I am newbie to this site and very new to Electrics also, so please excuse my ignorance. I have recently obtained Part P, 17 edition and 2392. As i am sure you are aware to gain access to NIC i need to carry out 2 jobs so they can be inspected by NIC (for a nice fee of course). I chose to change my very out dated CCU which went without too much hassle. I noticed when changing to the new board that the downstairs lighting circuit had 2 tails into the CB as it seemed to always had been like this i did a like for like change and thought would investigate after CCU change. I am now at the testing stage and after some investigation and elimination i have found that its 2 circuits on one 6A CB. 1 circuit serves the whole of the downstairs lights apart from the Porch light (which is where the CCU is) which is on the other circuit in the same CB. I am not sure why this has been done and when changing CCU noticed that all was original wiring and the porch is part of the original house.

Given there are 8 other lights down stairs, and working at 100w per light using O-law this equates to 3.4A and with the porch light even though on a different circuit its well within the limits of the 6A CB, question is, as this is going to be inspected by NIC, does the Porch light circuit need its own CB?

Sorry if i go on a bit and its a bit detailed, still new :)
 
Dont worry it fine on the same mcb, maybe it was added at a later date and the CCU was the easiest place to pick up a feed from.

All the best with your NIC inspection

Sy
 
noy

thing wrong with that. even though there are 2 "circuits" coming from 1 MCB, it's classed as 1 circuit, so you will get your R1+R2 and Zs readings from wherever, and record the highest reading on your cert.
 
Hi fella, see your new to the forum. before you get bombarded with answers from all. set aside the calculations bit and give the overall view of this situation a think. What do YOU think you should do and why ?
It will save everybody a lot of explaining if we know how your thinking addresses this situation first.
 
Thanks guys for all your feedback. I did do an inspection before changing CU and as i said in original post believed it wasn't going to cause an issue and would address later, however perhaps i should have addressed and investigated before hand.

As for my own thoughts, originally i thought was is the lighting on a ring circuit? of course after investigation i found 2 lighting circuits, you say put the calculation aside but i used this in my thought process and believed that 2 circuits on 1 CB shouldnt be an issue as the overall AMPS after calculations did not exceed the CB limit. I only asked my friend because being still new and not covered 2 circuits on 1 CB before and because i want this CCU change as one of my NIC jobs, i just wanted to make sure i was doing the right thing as at £300 per assessment I dont want to get it wrong the first time i do however appreciate your feedback.
 
if you have a spare way, then you can split them. if not, then they're fine as they are. as you say, the rating of the OCPD is not exceeded, so you're good to go.
 
As others have said its not a problem, some people don't like to see more than one cable in a breaker I don't see a problem with it myself as long as its not overloaded, common sence should provale over this. It could be confusing if the cables do different things especially if it covers more than one area eg: upstairs AND say kitchen lights. which tends to happen through lack of spare ways and should really be split up when at all possible, you can split the installation up as much as you like as long as its labelled correctly.
As long as you can jusitfy what you have done without being detrimental to the installation regarding identification, loadings and utilisation as tel said your good to go. Reason i said set aside the math initially was to ease more info out of you about your knowledge and how you are going to explain to your assessment.
Do expect some comments during your visit but its not all about what you have done but more about what you know.
 
I take that the porch light is on adequate sized cable for the breaker? I thought you need more than one for assessment? A few big jobs and one small or something, at least when i joined it was......... i think i might sell my test gear.....
 
You can also run a spur from the origin of the circuit...
 

Reply to 2 Lighting Circuits on one 6A CB in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock