Discuss Distribution circuit question in the Electrical Forum 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

L

LlandrilloSpark

I'm running a 30 metre length of three core 16mm armour to feed a garage conversion which could have a high loading.
The cable will be run from the external meter box where I will split the meter tails via a Henley
The problem is There is naff all room in the box and I can't fit a switched fuse in there to protect the armour as the main cut out is 100A
Can I put the switched fuse of another suitable protection device at the other end to protect against overload?
Cheers
 
can yo not fit a switch fuse in a suitable IP65 adaptable box on the wall close to the meter box ?
 
I'm running a 30 metre length of three core 16mm armour to feed a garage conversion which could have a high loading.
The cable will be run from the external meter box where I will split the meter tails via a Henley
The problem is There is naff all room in the box and I can't fit a switched fuse in there to protect the armour as the main cut out is 100A
Can I put the switched fuse of another suitable protection device at the other end to protect against overload?
Cheers



It is possible to do it that way. There are requirements though.

Regards Chris
 
I dont think the DNO would be too happy with that arrangement, if they found out of course.:biggrin5:

There wouldn't be anything wrong with what you suggest, further in to an installation but, not at the origin IMO.
 
I dont think the DNO would be too happy with that arrangement, if they found out of course.:biggrin5:

There wouldn't be anything wrong with what you suggest, further in to an installation but, not at the origin IMO.

I see no reason for the DNO to have issues. The installation if designed correctly would meet the requirements of BS7671.

Regards Chris
 
At least you didn't ask THAT dreaded question........!!

And yes, you need to protect the cable so will have to find some form of additional box to house it in.
 
The way I see it, the first 30M of distribution cable would be relying on their service fuse for protection against short circuit, albeit with the added overload protection at the load end.


I'm not saying it's wrong or non compliant but, knowing the DNO as we do they are bound to come across it, see a cable directly connect to their service fuse with no additional protection visible, put 2 & 2 together, make 49 and throw the toys out of the pram.
 
Just a Thought,

He can put the switch fuse/Isolator within 3M of the origin, suitably labelled of course, I don't know if that will help the Op any, as I cannot see the installation
 
Last edited:
The way I see it, the first 30M of distribution cable would be relying on their service fuse for protection against short circuit, albeit with the added overload protection at the load end.

True Lenny, though everyone seems to be happy using the Dnos fuse for short circuit when using standard circuits, after all its the fuse which Annex Za uses to limit Let through and allows the consumer units to be rated higher, also the standard circuits where the Dno's fuse is providing back up protection, the i2t is used for determining CSA.

Do you have discrimination(short circuit) between a 32 amp type B MCB and a 100 amp 1361, what about larger MCB's, on a short the Dno's fuse is now providing short circuit protection to your circuits.



I'm not saying it's wrong or non compliant but, knowing the DNO as we do they are bound to come across it, see a cable directly connect to their service fuse with no additional protection visible, put 2 & 2 together, make 49 and throw the toys out of the pram.

Regards Chris
 
Just a Thought,

He can put the switch fuse/Isolator within 3M of the origin, I don't know if that will help the Op any, as I cannot see the installation

Absolutely but, the issue was the service head being in an external meter cabinet with no additional room for a switchfuse.

Mounting an additional enclosure adjacent to the meter cabinet has been suggested.
 
Mounting an additional enclosure adjacent to the meter cabinet has been suggested.

Agreed Lenny, but I was thinking more on the other side of the wall to the DNO's cabinet, ie through the wall
 
Well id suggest he utilizes 433.2.2 part (i).

Regards Chris


He could & I'm not disputing that, I mentioned it earlier. The only point I raised was regarding the DNO and their inability to se the wood for the trees. They want (or at least mine do) to see the additional protection within 3M of their service head, end of. They wont be told any different and I just wanted to make the OP aware of it.

BS 7671 isn't the be all & end all.
 
He could & I'm not disputing that, I mentioned it earlier. The only point I raised was regarding the DNO and their inability to se the wood for the trees. They want (or at least mine do) to see the additional protection within 3M of their service head, end of. They wont be told any different and I just wanted to make the OP aware of it.

BS 7671 isn't the be all & end all.

Well just remind them of this;

1 Definition Network ESQCR

Consumer’s installations in buildings are not intended to be included in the definition. Such installations should comply with the requirements of BS7671 Requirements for Electrical Installations or those of other relevant standards. Electrical distribution systems on offshore installations are also excluded from the definition, e.g. oil rigs.

So tell them to concentrate on there network and you will concentrate on your installation to the relevant standards.

As for there equipment in a premise then there is also this;

ESQCR

Equipment belonging to distributors and meter operators which is installed on consumers’ premises must be suitable for itspurpose and safe. Examples of such equipment include: cables, meters, distribution boards, isolators and switches.Such equipment must also be electrically protected by fuses, cut-outs or circuit breakers. For safety and technical reasons the protective device should be situated as close as reasonably practicable to the supply terminals. Where flats are supplied by rising mains, duty holders should ensure that all equipment upstream of the supply terminals at each flat benefit from adequate electrical and mechanical protection.
In order to demonstrate compliance with the requirements of regulation 24(1) duty holders should adopt the standards of construction and installation necessary to comply with BS7671 Requirements for Electrical Installations.

Regards Chris
 
Last edited:
Wouldn't that mean the only protection the 16mm would have is the 100A service fuse? I wouldn't even consider that as an option! I would also be doing everything I could to rcd protect the armoured.
 

Reply to Distribution circuit question in the Electrical Forum 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

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
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