L
loz2754
Not necessarily. A final radial circuit can be wired as a tree with multiple branches, one or more of which branches could be connected to the same way, so it is still only one radial circuit.
J
John-SJW
G
GBDamo
It's an argument as old as time, but my take is...
The interpretation of 314.4 is all down to how you define a final circuit.
If the regulation was meant to mean a final circuit will consist of a single line conductor in the case of a radial and two line conductors in the case of a ring, then this is what they should have said.
In my mind a final circuit is exactly what a competent electrician had designed it to be, accounting for design characteristics and manufacturers instructions. Therefore, as spurs are permitted, where and how the electrician decides to make a spur is not restricted by 314.4.
- Aug 12, 2017
- 14,331
- 20,726
- 3,557,381
- 51
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Practising Electrician (Qualified - Domestic or Commercial etc)
Doesn’t #40 answer your own question?
I agree with #43 above
I agree with #43 above
J
John-SJW
Yes, as I can read and interpret English. It says final circuits must have their own way (mcb, RCBO).
J
John-SJW
There is no ambiguity in 314.4. The final circuits must have own RCBO or MCB.
A final circuit is any circuit whether it is a ring or radial, with any of them with branches, spurs, etc. It is clear in the writing of 314.4 they cannot be connected to one way.
- Sep 5, 2010
- 71,498
- 72,015
- 18,688
- 78
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Electrical Engineer (Qualified)
- Business Name
- Telectrix
but if you have 2 radials off 1 MCB, then those 2 radials combined are, by definition, 1 final circuit.
L
loz2754
Maybe you're confusing cables with circuits.
A circuit can consist of more than one cable connected to the source.
G
GBDamo
You arguing a logical fallacy, an argument from authority.
You claim there is no ambiguity where the constant debates on this subject clearly reveal otherwise.
Rather than state, as fact, "there is no ambiguity" you should say "I see no ambiguity" which is fine, its a personal opinion and one your entitled to.
If you could add a technical reason why this practice is unacceptable then fine but at the moment the argument seems to me to be "I don't like it and the regs say you can't do it".
When I originally mentioned this reg on this post, I said this was fine and happens a lot, there is one reg to be mindful of, and asked the question - "can the two legs be considered one circuit".
The last bit is key, as very often they can, but sometimes they can't legitimately be classed as one circuit due to ccc or ocpd requirements.
For example, at a recent EICR I found an unlabelled 30 amp rewireable fuse, testing showed it fed a sub main to a shed and apparently strangely two sockets in a utility room. Take front off board and find a 6mm and a 2.5mm live in the same fuseholder. One might logically guess the 2.5mm was a radial for the two sockets. In fact it was yet another radial for a boiler FCU. (the utility room sockets turned out to be a joint box off the 6mm)
In that situation I had no issue citing 314.4 as one reason it wasn't adequate, the ocpd wasn't suitable for the boiler circuit and the whole lot was downright confusing. Definitely two circuits in the same fuseholder.
But if the same OCPD is needed, the same CCC, and the total loading is suitable, it clearly becomes one circuit in my mind.
The last bit is key, as very often they can, but sometimes they can't legitimately be classed as one circuit due to ccc or ocpd requirements.
For example, at a recent EICR I found an unlabelled 30 amp rewireable fuse, testing showed it fed a sub main to a shed and apparently strangely two sockets in a utility room. Take front off board and find a 6mm and a 2.5mm live in the same fuseholder. One might logically guess the 2.5mm was a radial for the two sockets. In fact it was yet another radial for a boiler FCU. (the utility room sockets turned out to be a joint box off the 6mm)
In that situation I had no issue citing 314.4 as one reason it wasn't adequate, the ocpd wasn't suitable for the boiler circuit and the whole lot was downright confusing. Definitely two circuits in the same fuseholder.
But if the same OCPD is needed, the same CCC, and the total loading is suitable, it clearly becomes one circuit in my mind.
This is the crux of the matter. You ARE interpreting the wording incorrectly.
J
John-SJW
The text:
314.4 Where an installation comprises more than one final circuit, each final circuit shall be connected to a separate way in a distribution board
What don't you understand about the clear English 314.4 is written in?
J
John-SJW
- Jul 15, 2016
- 23,292
- 1
- 29,150
- 315,788
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Electrical Engineer (Qualified)
G
GBDamo
I wouldn't say incorrectly exactly just a little lacking in nuance.
Both sides of this debate are, after all, opinions.
I mean, if he follows his opinion he will never leave an unsafe situation but may limit the customer's options.
- Jul 15, 2016
- 23,292
- 1
- 29,150
- 315,788
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Electrical Engineer (Qualified)
This has been debated many times no harm in doing it again but can we keep it friendly.
G
GBDamo
You're just shouting the same thing louder.
A final circuit, in my opinion, is any number of suitable conductors fed from the same OCPD.
Then you are into the realms of good workmanship and following manufacturers instruction.
A ten legged radial all in one MCB = crazy.
A two legged radial in one MCB = perfectly acceptable.
Any technical objections yet or are we sticking to the sophistry?
Don't put a SPD on to a RCBO, use a MCB if the SPD type demands some form of OCPD below the DNO's fuse rating (many larger SPD are fine up to 125A or similar fuses).
- Firstly it is very likely to trip it on any modest surge event (as only 30mA equivalent to earth needed, averaged over the response time of the RCBO), disabling the SPD, and obviously taking out whatever other stuff the RCBO was feeding.
- Secondly there is a grater chance of the RCBO electronics being damaged if it has to divert a 10kA or more spike, even if only for tens of microseconds.
- May 16, 2018
- 694
- 1,130
- 1,168
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Practising Electrician (Qualified - Domestic or Commercial etc)
- If other, please explain
- Multi Skilled, fully qualified Electrical & Mechanical Engineer.
Currently Director of Technical Operations & Projects.
The crux of this lies in whether its acceptable to spur from the supply source of the final circuit to extend the circuit.
Consider this, would it be acceptable to spur off the circuit cable inside the CU using an appropriate junction connection?
- Jul 26, 2009
- 6,085
- 1
- 5,990
- 12,688
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Practising Electrician (Qualified - Domestic or Commercial etc)
L
Lucien Nunes
I believe the point is to specify the general configuration and function of a distribution board-based system rather than to define how many cables comprise each circuit. For example, it prohibits the 'tree system' where one main cable runs through every room in the house, with a fuseholder in each room tapping off that room's supply. This was popular in the early days of wiring. It also prohibits final circuits being paralleled up with distribution circuits and other random topologies.
- Aug 12, 2017
- 14,331
- 20,726
- 3,557,381
- 51
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Practising Electrician (Qualified - Domestic or Commercial etc)
I’ve just been in the BBB, looking at fig 15A and B, Spurs and fused spurs off ring and radial circuits. Although doesn’t mention 1.5mm on a 6A, but it does say……
- Dec 9, 2008
- 13,496
- 18,280
- 3,557,381
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Other
- If other, please explain
- C&G 17th edition regs
C&G 2382-18 (18th edition regs)
C&G 2394 Inspection & Test
C&G PAT
2 x BPEC electrical courses/exams
Weve been here before John. You've asked a question, received lots of good responses saying it's OK, and ow seem to want to argue the ---- using lots of bold writing and accusing people of not understanding English.
- Dec 9, 2008
- 13,496
- 18,280
- 3,557,381
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Other
- If other, please explain
- C&G 17th edition regs
C&G 2382-18 (18th edition regs)
C&G 2394 Inspection & Test
C&G PAT
2 x BPEC electrical courses/exams
Absolutely, nothing wrong with that. Same circuit, just a spur.
- Jul 15, 2016
- 23,292
- 1
- 29,150
- 315,788
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Electrical Engineer (Qualified)
- Dec 9, 2008
- 13,496
- 18,280
- 3,557,381
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Other
- If other, please explain
- C&G 17th edition regs
C&G 2382-18 (18th edition regs)
C&G 2394 Inspection & Test
C&G PAT
2 x BPEC electrical courses/exams
Ah, fair point. Sorry.
Would you never connect a 2nd cable to the OCPD od a radial circuit then?
- Jul 15, 2016
- 23,292
- 1
- 29,150
- 315,788
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Electrical Engineer (Qualified)
- Dec 9, 2008
- 13,496
- 18,280
- 3,557,381
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Other
- If other, please explain
- C&G 17th edition regs
C&G 2382-18 (18th edition regs)
C&G 2394 Inspection & Test
C&G PAT
2 x BPEC electrical courses/exams
Ah well, at least you didn't use bold text to tell me ?
G
GBDamo
Well that clears it up.
I know that refers to a ring but it confirms the principle of a spur at source is approved but the Bible.
J
John-SJW
What you are saying is that two final circuits can be joined, with one being a spur or sub of the other. The spur point just happens to be at the source - the way. Sorry the text is clear on that. No ambiguity. I even underlined the words.
J
John-SJW
No opinions involved. The text is abundantly clear. I advise many to swot up on English.
- Dec 9, 2008
- 13,496
- 18,280
- 3,557,381
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Other
- If other, please explain
- C&G 17th edition regs
C&G 2382-18 (18th edition regs)
C&G 2394 Inspection & Test
C&G PAT
2 x BPEC electrical courses/exams
I advise you speak to people with respect, rather than repeatedly asserting that your opinion is gospel and that other people don't understand English.
If you know the answer already then why ask the question? Or was it just to create an argument?
N
nicebutdim
To paraphrase Father Jack; this appears to be an ecuminical matter.
J
John-SJW
As a university graduate who had to extensively use and read English in studying and professionally all my life, I know simple English. I have written reams of technical documents and edited many others. It appears many cannot grasp something so fundamentally simple. Those who do not know English too well will ride along with the mob.
The text is abundantly clear - two final circuits cannot be connected to one way in and CU.
L
Lucien Nunes
We have two loads, A & B connected electrically in parallel to a DB way. The cables connecting them in parallel can run either [A-DB-B] or [DB-A-B]. The electrical implications of the two configurations are plain to see and don't seem to be in dispute. The argument is whether these two configurations have different textual descriptions, and therefore whether one of them is prohibited by a regulation.
In the meantime, people are connecting showers to RFCs, leaving CU busbar screws loose, running switch lines down the bare core of T+E, and being paid for it.
In the meantime, people are connecting showers to RFCs, leaving CU busbar screws loose, running switch lines down the bare core of T+E, and being paid for it.
- Dec 9, 2008
- 13,496
- 18,280
- 3,557,381
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Other
- If other, please explain
- C&G 17th edition regs
C&G 2382-18 (18th edition regs)
C&G 2394 Inspection & Test
C&G PAT
2 x BPEC electrical courses/exams
Two final rings - yes I agree.
Is your argument not wandering off again though?
PS, I have a very good grasp of the English language, and have proof-read technical documents at a previous company. I don't always choose to use verbose language when typing forum posts on a mobile phone keypad however.
J
John-SJW
I am being direct and open. I am not perfidious. Many here just cannot understand basic, simple English. They need to swot up. Simple.
- Dec 9, 2008
- 13,496
- 18,280
- 3,557,381
- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Other
- If other, please explain
- C&G 17th edition regs
C&G 2382-18 (18th edition regs)
C&G 2394 Inspection & Test
C&G PAT
2 x BPEC electrical courses/exams
Similar threads
OFFICIAL SPONSORS
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
