Circuit Cable to short.

[craig1]

Hello,

What method would be used if a circuit cable will not reach

the MCB termination? Would you crimp an extension inside the CU

or chase the individual circuit back to where its connected within

the circuit and add a longer length of cable.

THANKS
craig

[didthathurt]

Personally, I would crimp (using proper ratchet crimpers). However, doing so inside the CU can, on occassion, make routing the cables neatly quite difficult as the length of the crimp can be quite a proportion of the cable length inside the enclosure. If that looks like it might cause a problem in your box, you can cut the cable back and joint outside the box (stagger the crimped joints - its's far neater) using heatshrink to complete the job. You'll be able to give yourself all the cable you need that way.

[craig1]

You mean chisel out the plaster to locate the cables above the cu. Cut

the circuit cables then ratchet crimp a length of cable.

thanks for the info.

[didthathurt]

[TheGaffersSon]

For neatness, I wouldn't crimp inside the CU. Can you not run a new cable? Pain in the ar-se but is a better job. Or how about a JB in between the powerpoint and the CU?

[didthathurt]

You certainly could use a JB for this job. I would crimp (definitely outside the CU - but I try to be a bit circumspect when the alternative has no real argument against it other than convenience and personal preference) as the crimped joint is easier to fit into existing conditions (normally) and you don't have some of the siting problems you can come across when fitting JB's in already utilised locations. Here, for example, we already know the cable is a tad too short, so it's probably safe to assume the JB would have to be quite close to the CU which might involve drilling holes for the mount screws in the vicinity of other cables. Also, as the JB would have to be accessible, you may not be able to site it any further away depending on how the original cable is routed.
A new cable for that entire leg, for me, is the bonus prize solution, as any joint in a cable has the potential to become a problem - I would suspect the disruption so caused might militate against though, That's my thinking in going for the crimps just a little outside the CU in this case.
Does that help?

[TheGaffersSon]

didthathurt wrote:

You certainly could use a JB for this job. I would crimp (definitely outside the CU - but I try to be a bit circumspect when the alternative has no real argument against it other than convenience and personal preference) as the crimped joint is easier to fit into existing conditions (normally) and you don't have some of the siting problems you can come across when fitting JB's in already utilised locations. Here, for example, we already know the cable is a tad too short, so it's probably safe to assume the JB would have to be quite close to the CU which might involve drilling holes for the mount screws in the vicinity of other cables. Also, as the JB would have to be accessible, you may not be able to site it any further away depending on how the original cable is routed. A new cable for that entire leg, for me, is the bonus prize solution, as any joint in a cable has the potential to become a problem - I would suspect the disruption so caused might militate against though, That's my thinking in going for the crimps just a little outside the CU in this case. Does that help?

Agreed, replacing the whole cable would be the best option.

If it's too short I presume its a new cable, and isn't to late to be replaced.
IE, no tiles have been put down or anything.

The choice is yours, remember a JB has to be accessible so stick it away from the CU, underneath a floorboard. Like Didthathurt said, watch where you fix it if you do choose to stick it near the CU.

[JohnD]

If you're really lucky, and its a downstairs socket circuit, you can put a new socket in, close to the CU, and say it's for the maintenance man to plug in his tools and his RCD tester. then just run a new leg from the new socket to the MCB. Similar if it's the downstairs lights.

[securespark]

JohnD wrote:

If you're really lucky, and its a downstairs socket circuit, you can put a new socket in, close to the CU, and say it's for the maintenance man to plug in his tools and his RCD tester. then just run a new leg from the new socket to the MCB. Similar if it's the downstairs lights.

Except don't fit a 13A socket on the lighting circuit...!

[JohnD]

securespark wrote:

JohnD wrote: If you're really lucky, and its a downstairs socket circuit, you can put a new socket in, close to the CU, and say it's for the maintenance man to plug in his tools and his RCD tester. then just run a new leg from the new socket to the MCB. Similar if it's the downstairs lights. Except don't fit a 13A socket on the lighting circuit...!

Quite right, I was thinking of a shrouded batten holder or something