Use Second fused spur or single

[Yanni]

There is a fused spur that feeds the front security light of our property.
I want to add a second security light to the side of the property and can either feed it from the wiska box where the first security light is fed from or using a separate fused spur that already exists inside the property next to the first fused spur.

Inside, the second fused spur is fed from the first one and the previous owners have just left a redundant cable hanging on the outside.

what would you do? Remove completely the second fused spur and feed both lights from same wiska box or keep them on separate fused spurs ? I can also upgrade both spurs to RCBOs.

 

[Taylortwocities]

Either. It depends on the better wiring route.

Yanni, I do not understand this

I can also upgrade both spurs to RCBOs.
View attachment 263030

An RCBO goes inside the consumer unit.

 

[Yanni]

Sorry I meant change the spur to rcd.

 

[Taylortwocities]

Sorry I meant change the spur to rcd.

Not necessary for an external light. In any case, probably the circuit already has RCD protection in the consumer unit?

 

[winston1]

There is no point in feeding a FCU off another one. There will be no discrimination.

 

[yorkspark]

That rcd spur cannot be fitted on a non rcd protected circuit anyway, so don't bother changing

 

[EFLImpudence]

That rcd spur cannot be fitted on a non rcd protected circuit anyway, so don't bother changing

I think we have worked out that that belief is because of a misreading of the regulations and the meaning of 'additional'.

 

[opps]

That rcd spur cannot be fitted on a non rcd protected circuit anyway, so don't bother changing

I am not an electrician, I do not understand your post. Are you saying that an RCD cannot be used unless the consumer unit is RCD protected?

 

[securespark]

There is no point in feeding a FCU off another one. There will be no discrimination.

It could be that the second is fed from the feed terminals of the first, not the load terminals.

 

[333rocky333]

I am not an electrician, I do not understand your post. Are you saying that an RCD cannot be used unless the consumer unit is RCD protected?

I believe the regs state certain Bs numbers only can be used for the Rcd protection needed to conform with regs.
As the Rcd spur has a Different Bs number, not on the list. there is a belief by some they do not conform when used alone.

Edit
Bit more about it from Yorkspark here
https://www.diynot.com/diy/threads/summerhouse-outbuilding-wiring-thoughts.572568/#post-5016749

 

[EFLImpudence]

As above, I believe we have previously debunked that reason.

 

[opps]

I believe the regs state certain Bs numbers only can be used for the Rcd protection needed to conform with regs.
As the Rcd spur has a Different Bs number, not on the list. there is a belief by some they do not conform when used alone.

Edit
Bit more about it from Yorkspark here
https://www.diynot.com/diy/threads/summerhouse-outbuilding-wiring-thoughts.572568/#post-5016749

Thanks for the reply.

https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=104590

I know a few electricians follow the rationale outlined in post number 6- my (lay) interpretation is that the electrician is not legally required to replace the whole consumer unit if they want to add RCD protection to a spur. BTW, the OP was told that he was allowed to add a RCD protected spur by the Niceic.