Main Switch

[Jimmyb]

hello, Do you need a main switch in a domestic property if there are 2 boards next to each other being fed from a service block.

I was thinking of single point of isolation for the installation but some say if there near each you dont need to.

thanks inadvance

jimmy

 

[malcolmsanford]

Reg 537.1.4 Tells us

" A main linked switch or linked circuit breaker shall be provided as near as practicable to the origin of every installation as a means of switching the supply on load and as a means of isolation."

To me 2 boards would indicate 2 installations and so there should be a switch for each board and this is normally incorporated into the CU, don't these boards have main switches??

 

[Sintra]

I have always classed everything that is derived from the same service head and meter to be 1 installation whether there be 1 or 10 boards.

 

[johnboy6083]

According to the reg Malcolm quoted, even the isolators fitted by the DNO's are not suitable ( assuming an installation is as Sintra describes) as they are only rated for isolation, not on load switching. This would cause the contacts to degrade over time.

 

[JUD]

Post deleted

 

[telectrix]

as long as each CU has it's own main switch to BS 60947-3, it complies. an isolator between the meter and the CU's is purely for isolating the CUs from the supply.

 

[malcolmsanford]

According to the reg Malcolm quoted, even the isolators fitted by the DNO's are not suitable ( assuming an installation is as Sintra describes) as they are only rated for isolation, not on load switching. This would cause the contacts to degrade over time.

I think you'll find John that Functional switching for a BS 5419 (old type) or a BS EN 60947-3 can be achieved on load it is the on load for isolation that can not be achieved.

 

[oxocube]

I think its a common sense issue and all the arguments for and against have been rasied by others. But you come to a point of how many points of isolation are acceptable.

I reckon if the two points are in differnt locations ie not beside each other, then you need a single isolation point. And if you have more than two even in the same location then a single isolation point should be provided.