Adding fused spurs for appliances to existing ring no 30ma RCD old fuse box ?

[Hayd]

I have been asked to add 2 fused spurs supplying under unit dishwaher and washing machine to an existing kitchen ring. The fuse board has 3036 wire fuses and has a large 100ma RCD protecting it. TN-c-s system, earthing and bonding are fine. Is it okay to add these spurs or do I somehow have to add rcd protection to that circuit alone ( the customer does not want a fuse board upgrade which would probably be the safer option.)? There is also no room where the fuse box is to add any further boxes or devices.

 

[Sintra]

Have you got a copy of BS 7671 or the on site guide.

 

[bigbaddave]

Have a think about this one.. What is another way of RCD protecting your work? that will not cost much more.

But secondly does the said work need RCD protecting ??

 

[Paul.M]

Surface mount the cables (clipped direct) in the under cupboards and no RCD is needed (long as Zs and disconnection times are met). If that is not possible you will have to use conduit or an RCD socket but that looks naff in a kitchen.

 

[wildgoose]

Must be rcd protected fused spurs to meet regs. Also the cable from the ring to the rcd spurs, needs to be mechanically protected or visibly surface clipped.
I've previously converted the existing socket into a dual box (single socket with the rcd spur. This overcomes the connection wire difficulty above.

Finally, it's work being done in a kitchen so it must be LABC notified and that means a test report - easy if you are registered as you probably know??

 

[Hayd]

Must be rcd protected fused spurs to meet regs. Also the cable from the ring to the rcd spurs, needs to be mechanically protected or visibly surface clipped.
I've previously converted the existing socket into a dual box (single socket with the rcd spur. This overcomes the connection wire difficulty above.

Finally, it's work being done in a kitchen so it must be LABC notified and that means a test report - easy if you are registered as you probably know??

All as I thought, but just good to run things past more experienced sparks. I think best plan seems to be an external 30ma rcd mounted just outside where the fuse box is, then wire the kitchen ring to that before it goes back to the CU, to protect the whole kitchen.

Feel free to offer any better ideas.

Thanks

 

[wildgoose]

Ok but your customer doesn't want to upgrade the old 3036 fuseboard?? By rcd protecting the kitchen ring, you are of course now taking responsibility for that complete circuit. I hope it has not been modified too much in the past to make things difficult and that their no N/E faults or insulation issues?

Before you commit to doing it this way, I advise you do a few basic measurements from the fuse box end. Then you can make the call on which solution you offer to the customer with associated cost's.

I'm assuming you are a Spark and this is your customer - right?

 

[Paul.M]

Must be rcd protected fused spurs to meet regs. Also the cable from the ring to the rcd spurs, needs to be mechanically protected or visibly surface clipped.

Sorry Wldgoose that is incorrect. A spur from a RFC for a single or double socket for only one point (at a time) does not even need a FCU. Cable route is different, as you say it needs to be surface mounted, in conduit or on an RCD if in the wall less than 50mm from the surface of both sides of the wall.

Its also a MWC as well.

 

[Octopus]

All as I thought, but just good to run things past more experienced sparks. I think best plan seems to be an external 30ma rcd mounted just outside where the fuse box is, then wire the kitchen ring to that before it goes back to the CU, to protect the whole kitchen.

Feel free to offer any better ideas.

Thanks

So do you have the BGB or the OSG?

 

[Hayd]

So do you have the BGB or the OSG?

I have OSG & BS 7671, yes am a spark was just really checking others thoughts on the best way on going about it. Took r1,r2&rn values , checked Ze and zs of current ring and insulation test when looking at the job. All values well within tolerance stated in OSG for fuse type. I have to move a couple of sockets as well so will already be taking responsibility for the whole circuit.

After scouring the forums most seems to think adding an external 30ma RCD then replacing the fuse with a plug in MCB the way to go.

 

[wildgoose]

Sorry Wldgoose that is incorrect. A spur from a RFC for a single or double socket for only one point (at a time) does not even need a FCU. Cable route is different, as you say it needs to be surface mounted, in conduit or on an RCD if in the wall less than 50mm from the surface of both sides of the wall.

Its also a MWC as well.

Correct it doesn't but it must have rcd protection and either the rcd spur or rcd socket would in that case be the most appropriate solutions.

The spur solution by the way is what was being asked about on the original post and not a socket.

 

[Sintra]

A kitchen ain't a special location.

 

[wildgoose]

But under Part P they group "Special Installations, Special Locations & Kitchens" all in the same section (5) ie:- those areas needing additional requirements and therefore requiring LABC notification.

 

[Sintra]

Yea see that I've just had a read of section 5. No real special requirements for a kitchen apart from the notification. Just glad I don't do domestic and especially not in England or Wales :lol:

 

[wildgoose]

You are right there! Must be a huge number of jobs-worths making a very nice living out of all these complicated regulations.

Apparently in Europe, there's a whole city dedicated to training and creating these people - it's called Brussels

 

[D Skelton]

Since when have SFCUs needed RCD protection?!?! If the cable is surface mounted then add an SFCU for each appliance and a flex outlet below.

Some people seem to think that you need to whack an RCD on anything with an electron! "Sorry sir, I can't change the socket for you because the RCD protecting it isn't RCD protected, and the regs need me to RCD protect the RCD protection protecting the RCD protection. Also sir, that wooden front door of yours, is that...."

 

[Hayd]

Since when have SFCUs needed RCD protection?!?! If the cable is surface mounted then add an SFCU for each appliance and a flex outlet below.

Some people seem to think that you need to whack an RCD on anything with an electron! "Sorry sir, I can't change the socket for you because the RCD protecting it isn't RCD protected, and the regs need me to RCD protect the RCD protection protecting the RCD protection. Also sir, that wooden front door of yours, is that...."

The cables are not surface mounted they are to be buried but not over 50mm, also some of the sockets are being moved, so therefore they will all need protection by RCD as I understand it as they will all be on the same circuit and the newly moved sockets can be used for portable appliances.

 

[D Skelton]

The cables are not surface mounted they are to be buried but not over 50mm, also some of the sockets are being moved, so therefore they will all need protection by RCD as I understand it as they will all be on the same circuit and the newly moved sockets can be used for portable appliances.

You have six options available to you then:

1. Protect cables buried in walls in galv conduit or earthed galv capping and add RCD socket outlets/RCD SFCUs protecting socket outlets.
2. Use FP200, MICC or SWA in the walls and add RCD socket outles/RCD SFCUs protecting socket outlets.
3. Utilise electrical seperation as your protective measure so you don't need RCD protection.
4. Get the homeowner to become a fully qualified electrician so he becomes a qualified person thus the install not needing RCD protection.
5. Change CU to incorporate RCD protection.
6. Add a stand alone RCD in line with the kitchen ring/radial circuit.

I know which two of those six I'd be leaning towards

 

[Deleted member 26818]

Can't use FP200, on it's own, would still need another acceptable method of additional protection.
The skilled or instructed person exemption does not apply to domestic premises, as there are no Statutory Requirements, which pertain to them.
pBit confused as to why the OP states they intend installing a plug in MCB.

 

[D Skelton]

I always thought FP had an earthed metallic sheath that would make it suitable for that purpose, not that I've ever used it for such purposes or even thought about it. With regards to the instructed person comment, it was clearly meant in jest, as was turning the customers kitchen in to an electrically separate installation