Main switch on Three phase board

[Richard]

Hi,

Changing an old Three phase board in a school today which feed off-peak storage heating and underfloor heating. The supply Is TN-S.

The board were fitting in a Crabtree Loadstar, and comes supplied with a three pole isolator.

As this is effectivly the main board for the effected circuits, should the main switch also switch the neutral? Looking at BS7671

537.1.4 - A main switch intended for operation by ordinary persons, e.g of a householder or similar, shall interupt both live conductors of a single phase supply

537.2.1.1 - Every circuit shall be capable of being isolated from each of the live supply conductors. In TN-S or TN-C-S, it is not neccesery to isolate or switch the neutral conductor where it is regarded as being reliably connected to earth by a suitably low impeadance.


Just what to check i'm correct in thinking a three pole isolator will be ok.

Thanks

 

[Guest123]

A TP isolator will be fine in this instance.

 

[Richard]

Fair enough! So one re-instated there will be no means of disconnecting the board or any of the circuits from the neutral conductor?

To me it doesn't quite sound right, but I can find a reg that says that..!!

Thanks

 

[Guest123]

537.2.1.1 - Every circuit shall be capable of being isolated from each of the live supply conductors. In TN-S or TN-C-S, it is not neccesery to isolate or switch the neutral conductor where it is regarded as being reliably connected to earth by a suitably low impedance.

:wink5:

 

[Richard]

lol Yea, your not wrong!

 

[Guest123]

lol Yea, your not wrong!

Don't look for problems that don't exist, you'll drive yourself up the wall.

I do understand where you're coming from though.

 

[Richard]

Nice one, thanks for the info

Rich