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Hi Folks,

If I'm extending a lighting circuit, (adding two pendants and an outside light) from an existing pendant but the board doesn't have any protection (an old BS3036 fuse board) What's the best way to add RCD protection?

The new cable for the switches can't buried more tore than 50mm deep and I don't want to whack an RCD FCU anywhere as they are quite bulky.

What would be the best course of action to take to install this circuit so it complies with the Regs?

Thanks,
T
 
D

Deleted member 26818

Install an RCD in an enclosure next to the fuse board.
Feed the RCD from the lighting circuit fuse and then feed the lighting circuit from the RCD.
 

Fitzy

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Arms Access
You could install a 3 module consumer unit fed from your 3036 board, then install an RCD and 6a mcb for the lighting circuit in this cu, which is notifiable work.

But, by the time you’ve gone to all that effort for just 1 circuit, you’d be better off upgrading the complete board and protecting the whole house.
 

GBDamo

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Subscribed Member
Install an RCD in an enclosure next to the fuse board.
Feed the RCD from the lighting circuit fuse and then feed the lighting circuit from the RCD.
You forgot...

..and pray to god the existing circuit is fault free.
 

GBDamo

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Subscribed Member
You could install a 3 module consumer unit fed from your 3036 board, then install an RCD and 6a mcb for the lighting circuit in this cu, which is notifiable work.

But, by the time you’ve gone to all that effort for just 1 circuit, you’d be better off upgrading the complete board and protecting the whole house.
If done SpinLondon,s way would it still be notifiable? the OCPD at the origin of the circuit would be unchanged, only addition of additional protection.
 
  • Thread Starter Thread Starter
  • #7
I figured the RCD FCU at the origin would be the simplest solution.

As the old Wylex Fuses for lifting circuits are rated at 5a... What size fuse would I put in the RCD FCU? A 3a?

I believe there are currently 4 pendants on the circuit.

I don't think it would be notifiable because i would just be adding a fuse on the existing wiring, it just happens to be next to/near the fuse board?

Correct me if I'm wrong.
 

Taylortwocities

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Arms Access
As the old Wylex Fuses for lifting circuits are rated at 5a... What size fuse would I put in the RCD FCU? A 3a?
You need to get your discrimination tables out to answer that one!
My gut feel is that it won't discriminate.

But, whoa fella. Why an RCD FCU?. Just install an RCD.
You do not need any additional fusing.
 
Last edited:

GBDamo

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Subscribed Member
I would say the fuse is largely irrelevant as it is not needed to provide protection, the fuse in the DB is doing that.

All yo really want is an RCD.

Slap a 13A in it.

If such a beast existed, you could fit a non fused RCD spur.

Tin hat on.
 
D

Deleted member 26818

You need to get your discrimination tables out to answer that one!
My gut feel is that it won't discriminate.

But, whoa fella. Why an RCD FCU?. Just install an FCU.
You do not need any additional fusing.
Circuits supplying luminaires now require 30mA RCD protection.
 
  • Thread Starter Thread Starter
  • #14
I just thought it would be cheaper and simpler to just add an RCD FCU would it now?

Just means I can split the existing cable, add the RCD FCU in between and be done with it?
 
D

Deleted member 26818

I just thought it would be cheaper and simpler to just add an RCD FCU would it now?

Just means I can split the existing cable, add the RCD FCU in between and be done with it?
One of the problems with that idea, is the requirement is to provide RCD protection for the circuit, not just part of the circuit.
 

GBDamo

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Subscribed Member
The simplest and most stress free way to do this would be to put the RCD FCU at the point you connect to the old circuit.

This would require a sensible, accessible location.
 

GBDamo

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Subscribed Member
One of the problems with that idea, is the requirement is to provide RCD protection for the circuit, not just part of the circuit.
I think his intention was to do this at the DB.

Why would the whole circuit need RCD protection?

Surly it would only be a requirement for the addition, or have i misunderstood the requirement again?
 
D

Deleted member 26818

I think his intention was to do this at the DB.

Why would the whole circuit need RCD protection?

Surly it would only be a requirement for the addition, or have i misunderstood the requirement again?
It’s in the wording of the Regulation, same as for locations containing baths or showers.
The requirement is for the circuit to be provided RCD protection.
This is not the same as protecting cables concealed in walls or protecting items plugged into socket-outlets.
 
  • Thread Starter Thread Starter
  • #20
I figured I could put the RCD FCU next to the DB?

So the existing cable that comes from the fuse to the lighting circuit, essentially, split that in two, connect the side from the fuse to the supply side of the RCD FCU and then the cable that then runs to the lights on the load side of the RCD FCU....

That way the whole circuit is protected and the new fused unit stays out of sight but would still be accessible and I don't have to tamper with the fuse board too much (aside from safe isolation and testing etc)

Again, please feel free to correct me if I'm wrong?
 

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