agricultural building

[Pat Tester]

Assistance please anyone with a reg book (can't find mine, may have to empty van in morning)
supply is TT
from meter into 4 pole RCD is it 300mA ? this is supplying via two fused switch in swa two separate fuse boards one single phase one three phase

Question all socket outlets on 30mA but should other circuits be on 100mA delay rcd to provide discrimination ?

many thanks

 

[spark 68]

Here you go from GN7

 

[Engineer54]

Well that answers a few questions on why agricultural installations are or tend to be less than satisfactory. As i say i wouldn't leave lighting and other non socket outlet circuits sitting on a remote or even a local 300mA RCD on a TN system, let alone a TT system....

 

[spark 68]

That needs to be considered with other regs though E54, the wiring containment is meant to be suitable for the environment, which to all intents and purposes means steel conduit in the animal sheds for example

 

[Engineer54]

That needs to be considered with other regs though E54, the wiring containment is meant to be suitable for the environment, which to all intents and purposes means steel conduit in the animal sheds for example

So what about the standard 300mA RCD's at the main distribution panel?? Potential discrimination problems with every building on the diagram. Nope, i think i'll stick to my own system set-up, that layout distribution diagram is just pants!! lol!!

 

[spark 68]

I agree with you btw, BS7671 is the minimum standard.

I added another file in the above post, and the notes say not exceeding certain mA ratings.

 

[JD6400]

I too do not disagree with you Engineer54 , a 300mA S type for all other circuits is far from airing on the side of caution !
And even 10Ma on finals in certain situations is a good choice , imo !
My post was not to question your interpretation on good practices , it was more in the vain of "Oh bug"er , I should have known that one ! ":blush5:

 

[Engineer54]

I too do not disagree with you Engineer54 , a 300mA S type for all other circuits is far from airing on the side of caution !
And even 10Ma on finals in certain situations is a good choice , imo !
My post was not to question your interpretation on good practices , it was more in the vain of "Oh bug"er , I should have known that one ! ":blush5:

If going by the overall multi building drawing, all those 300mA RCD's should be S type and not standard RCD's. Lighting and other unprotected circuits shown within the local CU/DB's should also be RCD protected. That section covering TT installations in BS 7671 really does need a complete overhaul. Some of it is little better than you would expect to see in a Third Country Standard!!