changing a consumer unit

[saass]

we will be changing our consumer unit in the near future, it is unlikely that there's enough cable on the ends of some circuits for them to reach the required terminals in the new unit.

Of particular concern is a ring main that was added to the existing unit some years ago, it is unlikely that the cpc of the (say)outgoing leg is long enough to reach the earthing terminal in the new unit, I'm interested in knowing what is considered industry best practice in this scenario.

I'm perfectly aware that a terminal block and a length of appropriate sized and sheathed wire can extend the cpc but is this a "textbook" practice or should a junction box be added to the leg and a new bit of t/e run from the jb to the unit.

similarly what would be considered best practice if all of the existing circuits' ends fell short in this manner

just interested in knowing the best practice solution to such problems
and yes i do know the work is notifiable and that the installation will need to be tested/certifcated etc

 

[ban-all-sheds]

As you know that you know that in reality you'll have to have an electrician do the swap for you, so you might as well leave all such decisions to him.

 

[ericmark]

There are many different ways to extend cables. Common is use of junction boxes. Although the crimp is accepted I have found many specially on solid cores not doing a good job and over heating. Likely due to use of cheap crimp pliers. But experience tells us what will work where. And with a job like consumer unit change then one does not do it unless one has the experience required.

I would advise since the LABC charges are so high it's not worth DIY'ing on this type of job. Will likely be cheaper to get it done for you.

 

[saass]

thanks for the prompt replies, Mr shed you miss the point,perhaps I'd like to be able to judge a potential contractor by the ability to solve problems the way that it SHOULD be done, to do this I need to be armed with this knowledge myself, that's why I was asking specifically about best practice

 

[ricicle]

Why are you poking around in your existing consumer unit ?

Cables that are not long enough will possibly be the least of 'the electrician's' concerns.

 

[1john]

Agreed with Ricicle, more pressing matters will be main equipotential bonding and insulation resistance readings along with CPC continuity rather than extending a few circuits.

There are several ways to acheive this, equal amounts of contractors will have opinions as to which way is the best way.

 

[sparkwright]

There may be some slack on the cables that can be pulled from wherever they go. If the cables are not long enough to enter the new board it is common to extend using junction boxes, or a pattress + blanking plate + connector blocks, or sometimes even an enclosure with din rail connectors.

If the cables enter the new board, but the wires are too short, line crimps or connector blocks are the norm to extend them.

 

[holmslaw]

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[securespark]

Any spark not proceding in this manner is a crook and a con man, you have been warned.

While I agree a PIR is the ideal way to proceed, I think it harsh to label an electrician who does not as a crook and a conman.

 

[holmslaw]

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