Thoughts please | Page 5 | on ElectriciansForums

Discuss Thoughts please in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

Each 20A load would need a 20A fuse to protect the 2.5, surely without this then is one of the loads increased through whatever reason, the 2.5 would melt well before the 100A tripped.
I'm with shanky887614 on this one.

2.5mm 100a mcb over-rated

I'm really surprised at the fundamental lack of understanding regarding section 434 a large number of sparks seem to show!
 
I admire their natural suspicion of cable protection through a downstream protective device though. It's difficult to feel good about, regs or no regs. One might argue that a good design goal is to not have anything unexpected in it? I'm trying to think of something bad that might happen if someone working at one of your 20A loads blithely assumed there must be adequate upstream protection for the cable. Idiot proof designs are to be preferred.
 
The basic methods of overcurrent protection at NVQ level 3 is not to teach S/C protection up stream and O/L downstream. This is probably why some people have problems getting their heads around a non fused 2.5mm2 spur at the origin of an RFC.

However, your design does not take into account section 314 unless this is a German lash-up on one circuit.....
 
It's the same sort if thing as a 10A lighting circuit wired in 1.5mm to klick multiple point lighting box then having 0.75mm flex from the klick plug to the fittings.

As its affixed load at the end of the 0.75 flex you can never overload the flex. But you need 1.5 and a 10A o/c to have all the fittings on one circuit.
 
As far as the original layout is concerned, (showing an over current device instead of just loads) this would be considered as an unconventional circuit as far as BS7671 is concerned. Another example of an unconventional circuit would be the ''Lollipop Ring Circuit, again perfectly acceptable providing it meets certain criteria. So providing due care and attention has been applied in the OPs design and installation it's perfectly fine if maybe not ideal!! Unconventional circuits are permissible under BS7671, if the designer can substantiate by calculation and method, etc. Our American (and even some of our European) friends quite often apply this type of distribution circuit.

The problem being with all the critics here is, that many here need an actual Reg No, to put against any specific, or they become flummoxed, or totally flummoxed. The Reg's are not a step by step guide, or a ''How To-Do book''!! That's not what the Reg's were ever intended to be, they actually require a reader to hold a good basic knowledge of electrical work and theory!!!
 
Last edited by a moderator:
We get this argument in rock and roll whereby you arrive at a venue to find the house supply/outlets are physically and electrically larger than the inputs to the touring distribution that you're using. Typically a 125/3 > 63/3 or 400/3 > 300/3 scenario - so we carry jumper adaptors to suit. Some of the venues go ape and just can't get their heads around the fact that if I have d/s OL protection at 'source' then it doesn't matter that the feed cable is down-sized from the source S/C protection.
 

Reply to Thoughts please in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

News and Offers from Sponsors

  • Article
Join us at electronica 2024 in Munich! Since 1964, electronica has been the premier event for technology enthusiasts and industry professionals...
    • Like
Replies
0
Views
303
  • Sticky
  • Article
Good to know thanks, one can never have enough places to source parts from!
Replies
4
Views
819
  • Article
OFFICIAL SPONSORS These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then...
Replies
0
Views
897

Similar threads

This fella puts his face to it about halfway through, he has an opinion on the very subject.
Replies
42
Views
4K
  • Article
This is an RSS feed of thread: ADVICE for young plumber required please staffs/midlands Content of the thread: hi all, posting on behalf of my...
Replies
0
Views
260

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

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top