Spur or new circuit?

[D Skelton]

Hi guys,

My latest customer wants a couple of extra sockets installed. He has no RCD protection and no spare ways in his CU. He is not wanting a new CU so I have concluded that the way I would like to do this job is to spur of an existing 32A MCB into a 1 way RDC board with 6mm cable. Then instal a radial circuit for the sockets from a 20A MCB in the RDC board. Now I can't see a problem with this but can any of you?

Also, am I right in thinking that as my installation would technically be a spur, and not a new circuit, I would only need to complete MWC?

 

[Hawk81]

Why are you bringing a 6mm from the 32amp mcb? I would not be happy squeezing a 6mm and two 2.5mm's into one mcb. Can you not fit henleys on the main tails then make your new board separate installation.

 

[Guest123]

Is this existing 32A MCB supplying anything else already??

Could you not install service blocks in the supply tails & feed your new CU that way???

 

[D Skelton]

splitting the tails is not an option unfortunately, sorry, i should have pointed that out at the start, this is the reason i have to ask this question. the 32A breaker feeds a ring supplying 6 sockets as far as i can tell

 

[Octopus]

What load is the customer intending putting on the extra sockets. If its TV's and hifi couldn't you simply add a FCU/RCD unit off the existing ring and run a 2.5mm spur with the sockets on it?

 

[PC Electrics]

Why not simply fit an "off board" RCD (in a 2 mod enclosure) next to the existing board and run the existing ring through it (subject to testing, of course). Now that you've added RCD protection to the existing ring you can extend or spur from it to your hearts content.
or RCBO the existing RFC if you can get them (try obsolete mcb rcd rcbo mccb)

 

[i=p/u]

just spur off ring and use socket outlets with rcd incorparated.

 

[Hawk81]

just spur off ring and use socket outlets with rcd incorparated.

That would only work if the cable to the new sockets does not need to have RCD protection and if he is spurring the 2 sockets from different parts of the ring.

 

[i=p/u]

kk yeah, so socket outlets with rcd incorpared , they only for appliances that are plugged in and cable after???

 

[Hawk81]

Yes they are

 

[i=p/u]

so if he kept his cable at>50mm , he fine to just add socket outlets with rcd,

 

[Hawk81]

Yes surface cables or cables in a earth metal ducting or burried greater than 50mm

 

[i=p/u]

aye i know this stuff, have a question for you tho.. yes another. say you had a ring circuit and you cut the two leg in attic and terminated in juction boxes and then added another two legs in for different socket outlet,would this still be a ring? or isit a ring within a ring as ive heard some say

 

[Hawk81]

If you have 2 junction boxes then it is extending the ring.

 

[i=p/u]

aye 1 junction box for each leg. so what is a ring within a ring? you ever done much work down coleraine area, do you know where suppliers is down that direction or what their called. have we job on monday in porststewart??