TNS and 315a bs88

[Engineer54]

But they might compromise at 2x DB next to each other if it avoids then having the RCD they obviously don't want

But the switch fuse will still be at the origin of the installation and this is where the problem is, the final DB MCB's shouldn't have a problem with the Zs values being quoted above...

 

[davesparks]

But the switch fuse will still be at the origin of the installation and this is where the problem is, the final DB MCB's shouldn't have a problem with the Zs values being quoted above...

But with 2xDB at the far end he could run 2x smaller sub mains which might have a more achieveable max Zs

 

[Engineer54]

Were now getting into the realms of over design just to try and cater for a higher than expected Zs. So now you'll need a suitably sized front end isolator switch, rated at say 300A, Two suitably sized switch fuses rated at say 125/150A, and two suitably sized DB's......

 

[ImpededLoop]

Were now getting into the realms of over design just to try and cater for a higher than expected Zs. So now you'll need a suitably sized front end isolator switch, rated at say 300A, Two suitably sized switch fuses rated at say 125/150A, and two suitably sized DB's......

A lot depends on the layout of the building. If positioning two distribution boards in different places reduces the length of the final circuits, it may be advantageous.

 

[Engineer54]

A lot depends on the layout of the building. If positioning two distribution boards in different places reduces the length of the final circuits, it may be advantageous.

It's not what happening here though is it?? The planned position of the DB is stated to be 10 metre's away...

 

[ImpededLoop]

It's not what happening here though is it?? The planned position of the DB is stated to be 10 metre's away...

It is indeed but it might give the OP food for thought on other options. Sometimes bouncing ideas around can lead to alternative solutions.

 

[Engineer54]

It is indeed but it might give the OP food for thought on other options. Sometimes bouncing ideas around can lead to alternative solutions.

Very true!!