School block Swa supply | Page 2 | on ElectriciansForums

School block Swa supply

Post new thread

Discuss School block Swa supply in the UK Electrical Forum area at ElectriciansForums.net

cliffed

cliffed

-
Arms
Joined
Dec 20, 2009
Messages
2,173
Reaction score
654
Location
Worcester
What code would you give for a Swa supply 3p/N,95mm.
Supplies remote school block,2 storey,no main earth conductor,using sheath,the main earth bonding originates from this Swa,for this block,@ Main Panel board,& is 16 mm
The main earth @ origin is 120mm,Main bonding 50mm.
Cheers
 
Sort by date Sort by votes
I am guessing the OP is concerned more so about equipotential bonding in the block as this will need to meet the requirements of the size and nature of the supply and if my brain serves me correctly :rolleyes:, you cannot utilise the SWA sheath to satisfy this, it would need to be a dedicated core or a seperate conductor.... this is all assuming that equipotential bonding is required in the block itself?

It doesn't help and only confuses matters when you get muddled up with your terminology of how you describe the layout - it is a sub-main therefore using the term 'main earth' is incorrect as that is your primary earth conductor at the origin.
 
Upvote 0 Downvote
The PEN conductor and not the main tails would need to be 150mm or above for a requirement of a 50mm copper bonding conductor, so despite the fact it’s 50 mm in the main building could be down to an over specced original design and it maybe even larger than what is required.
It’s the PEN conductor which determines the required size of your bonding conductor however it’s most probably correct that your swa armour is going to be well undersized.
Sometimes you just have to assume it was designed correctly if you have no original design information, the existing building I mean and not the added block.
 
Upvote 0 Downvote
As above - you need to verify the requirements of the install and confirm them for us before we can comment, where required to be 50mm the equipotential bonding is there for safety reasons and is sized so to deal with network faults when associated with TNC based supplies, for example the N/E sheath of a PEN conductor suffers corrosion, this can lead to high resistance or even broken Neutral which can lead to high currents finding alternative paths through local installations.

EDIT- in answer, the SWA armour will probably be able to handle such a situation as it meets CSA compliance but falls short of regulations, this thus is not a safety issue but more so a compliance breach.
 
Upvote 0 Downvote
This only goes up to 70mm,,Main bonding over that is 50mm
 

Attachments

  • [ElectriciansForums.net] School block Swa supply
    DC428654-85F5-4DEA-B46B-6DFDD73F0D93.png
    19.4 KB · Views: 25
Upvote 0 Downvote
Ian1981 said:
The PEN conductor and not the main tails would need to be 150mm or above for a requirement of a 50mm copper bonding conductor, so despite the fact it’s 50 mm in the main building could be down to an over specced original design and it maybe even larger than what is required.
It’s the PEN conductor which determines the required size of your bonding conductor however it’s most probably correct that your swa armour is going to be well undersized.
Sometimes you just have to assume it was designed correctly if you have no original design information, the existing building I mean and not the added block.
Click to expand...
Thanks,agree on that, so a code 2 regarding undersizing of earth bonding cable
 
Upvote 0 Downvote
cliffed said:
This only goes up to 70mm,,Main bonding over that is 50mm
Click to expand...
Not sure what that’s off but bonding on a pme arrangement has nothing to do with the csa of the line or neutral conductors in the consumers side, it’s the DNO PEN conductor csa you need plus the DNO May stipulate a csa regardless
 
Upvote 0 Downvote
You really need to use the correct terminology when discussing or asking questions about this sort of thing.
Talking about main earth's and using an SWA sheath as cpc makes it appear confusing or that you don't know what you are talking about.

The SWA sheath is made of plastic, it's the armour which is under the sheath which can be used as a protective conductor.

Mixing up terms like CPC, main bond, main earth etc confuses the issue a lot.
 
Upvote 0 Downvote
davesparks said:
You really need to use the correct terminology when discussing or asking questions about this sort of thing.
Talking about main earth's and using an SWA sheath as cpc makes it appear confusing or that you don't know what you are talking about.

The SWA sheath is made of plastic, it's the armour which is under the sheath which can be used as a protective conductor.

Mixing up terms like CPC, main bond, main earth etc confuses the issue a lot.
Click to expand...
Agree,my wording may not be 100%,I know the armouring can be used for cpc,Main earth terminology was incorrect,to ask if I know what I’m talking about,seems a bit rude,but hey oh,have a good bank holiday.
 
Upvote 0 Downvote

Reply to School block Swa supply in the UK Electrical Forum area at ElectriciansForums.net

Similar threads

C
Best method to calculate 4 core SWA current rating for two pairs of 1PH line conductors
A picture paints a thousand words so here's an SLD showing my installation and some annotations to show the proposed relocation of the DC...
Replies
12
Views
1K
craig1410
C

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