Three phase TT install with distribution circuit and RCBOs

[leesparkykent]

I have an Install where a 16mm 4core has been installed previously. ATM the SWA is coiled up either end At the supply which is a barn converted in to an office for the homeowners business and plant room in new extension to the house. There is no PME available as over head, in the middle of no where and in an earlier life was a farm. My intention is to install a 100mA time delayed RCD at the supply in the office mains room and then a fused switch/switch fuse for the distribution circuit. In the plant room at the end the distribution circuit I want to install a 3 phase DB but this is where it gets a little tricky........All the circuits that need additional protection my means of a 30mA RCD will have to be put on RCBOs however I'm struggling to find single pole switched neutral RCBOs. In a single phase installation I would use SBS compact RCBOs as they are single pole switched neutral but SBS don't do three phase DBs etc. Is any one aware of a brand where I could achieve this or think of another idea? Cheers Lee

 

[Andy™]

1 board per phase?

 

[leesparkykent]

1 board per phase?

Yeah I'm starting to think its my only option. Shame though as would of been a lot better to use a DB.

 

[ProDave]

It's TT because it was (is) a farm NOT becaue it is overhead feed. I have seen plenty of houses with overhead feed and PME.

+1 to three SP db's and happy to reccommend SBS
 

 

[leesparkykent]

It's TT because it was (is) a farm NOT becaue it is overhead feed. I have seen plenty of houses with overhead feed and PME.

+1 to three SP db's and happy to reccommend SBS
 

Yeah I have also but thought I would include it as don't want "see if the supply can be converted to PME" its not an option here.

 

[leesparkykent]

http://www.doepke.co.uk/cons2/cdtable.html I wonder if these could make something up with a four pole mains witch and three RCD's fed off each phase. might pop them an email

 

[Tony S]

Yeah I have also but thought I would include it as don't want "see if the supply can be converted to PME" its not an option here.

Why not.

If Ferg drops by he can put you straight on that subject.

I used a picture of his supply cutout in KB transformer neutral earth connections.

 

[leesparkykent]

Why not.

If Ferg drops by he can put you straight on that subject.

I used a picture of his supply cutout in KB transformer neutral earth connections.

Because the DNO wont do it. They have no obligation to provide you with an earth just to maintain it if they do provide you with one.

 

[Tony S]

Because the DNO wont do it. They have no obligation to provide you with an earth just to maintain it if they do provide you with one.

Have you asked the DNO for a reason why they won’t provide a customer earth?

The reason I cited Ferg’s supply is it is CNE to get around the eight metre rule.

It seems the wilds of Scotland are far advanced than southern England.

 

[leesparkykent]

Have you asked the DNO for a reason why they won’t provide a customer earth?

The reason I cited Ferg’s supply is it is CNE to get around the eight metre rule.

It seems the wilds of Scotland are far advanced than southern England.

no I haven't but this is a builders own house so cost may be a factor lol

 

[Tony S]

no I haven't but this is a builders own house so cost may be a factor lol

It costs nothing to ask.

If this is a new supply then the cost of the DNO driving a rod near the cutout will be absorbed in the overall price.

 

[leesparkykent]

Yeah maybe I should try. Its an existing supply.

 

[Sidewinder]

Is it separate overheads or ABC's?

 

[Tony S]

https://library.ukpowernetworks.co.uk/library/en/g81/Miscellaneous/Other/OHL+Design+Manual+-+Section+1+-+Aerial+Bundled+Conductor+(ABC)+Low+Voltage+Mains+and+Services.pdf

Page 50 onward covers PME and ABC’s

 

[Sidewinder]

Who's the DNO?