Extending Circuits

[ban-all-sheds]

Fair enough - although it would only be a token impediment to tinkering!

My memories of student nurses remind me that they are often far from averse to a bit of tinkering.

 

[JohnW2]

You experience in the aircraft engineering trade will also tell you that the fewer joints and components in a circuit the better.

Indeed. However, in this case, unless the existing meter-side tails are long enough to reach the new CU (or are going to be replaced, which would obviously involve additional hassle), there would still have to be Henleys, hence exactly the same number of joints - and, given that the isolator would virtually never be operated, the chances of it 'failing' must be vanishingly small.

Some may argue (oh yes they will) that one can totally isolate the consumer unit by having an isolator but, in your domestic installation, it really is only of any use when the consumer unit is being changed; and that is what you are about to do; so it probably wouldn't be used again for another 20 years…..

I am personally pretty 'neutral' in terms of the isolator issue. However, CUs vary in relation to how well protected are the supply-side connections/terminals of the main switch - one often has to have ones hands very close to them when doing things with neutral and/or earth bars - so I personally always welcome the opportunity to isolate the entire CU (with an external isolator) when 'playing around' within it!

****TTC starts wondering who is going to break the seals****

Assuming that you're talking about the seals on the Henleys, and given that they are presumably 'unofficial' seals, it doesn't really matter, does it?

Kind Regards, John

 

[sparkwright]

I suspect removing the Henleys and adding an isolator is going to be difficult for the electrician.

I don't know what his policy is on working on live stuff.

Can't really see a major issue with a row of round 20 and 30 amp (a probably a 60 amp) junction boxes to extend the circuit cables, TBH.

True it won't look particularly good, but this is just a cupboard under the stairs.

You must have what you think looks best, if it's suitable.

Whatever you do, DO NOT let him just use the old fuse box as a big junction box. That would be rubbish.

Back to isolators, those MEM or Lewden or whatever they're called ones are the best. You know the ones. Pictures...

 

[JohnW2]

I suspect removing the Henleys and adding an isolator is going to be difficult for the electrician. ... I don't know what his policy is on working on live stuff.

Indeed - but exactly the same issues arise in relation to changing the CU, don't they? [and, in passing, hands up all those who can put their hand on their heart and say that they have never removed or connected cables to a live Henley!]

Can't really see a major issue with a row of round 20 and 30 amp (a probably a 60 amp) junction boxes to extend the circuit cables, TBH. ... True it won't look particularly good, but this is just a cupboard under the stairs. You must have what you think looks best, if it's suitable.

I agree that would be functionally more-or-less as good as any other approach - as you say, it really comes down to aesthetics. I personally find the rectangular MK 30A ones more pleasing to the eye in such situations (i.e. when there is a 'line'of them) - but it's really just a personal choice.

Kind Regards, John

 

[ban-all-sheds]

and, in passing, hands up all those who can put their hand on their heart and say that they have never removed or connected cables to a live Henley!

True it won't look particularly good, but this is just a cupboard under the stairs.

Look where that sort of thinking can lead:

 

[bernardgreen]

Junction boxes

• bernardgreen
• 13 May 2011
• 6

All junctions boxes must be accessible

 

[RF Lighting]

Back to isolators, those MEM or Lewden or whatever they're called ones are the best. You know the ones. Pictures...

View media item 8401

Untitled

• RF Lighting
• 27 Aug 2014
• 2

 

[sparkwright]

Don't mean those ones!

 

[sparkwright]

Back to isolators, those MEM or Lewden or whatever they're called ones are the best. You know the ones. Pictures...

MEM800KMF. Click do a similar version.

 

[JohnW2]

Back to isolators, those MEM or Lewden or whatever they're called ones are the best. You know the ones. Pictures...

MEM800KMF. Click do a similar version.

The KMF is a switch-fuse, not just an 'isolator'.

Kind Regards, John

 

[sparkwright]

Valid point, valid point.

We don't need a fuse in this case, assuming the tails are short.

 

[Greenie9657]

Thanks everyone for your input. I was planning to move the meter outside and then a switch fuse would have been needed as the tails would have been more than 3 meters in length. But I soon got rid of that idea when the DNO wanted a mortgage to move it. Robbing gets!

 

[ban-all-sheds]

Back to isolators, those MEM or Lewden or whatever they're called ones are the best. You know the ones. Pictures...

 

[RF Lighting]

That's the same one I posted pictures of. I've never seen an unjointed length of meter tail burn out

 

[JohnW2]

That's the same one I posted pictures of. I've never seen an unjointed length of meter tail burn out

I wouldn't have expected that you would have done! However, as I wrote before, it depends upon what alternatives are being contemplated - if the alternative under consideration were to retain Henleys, then the number of joints/terminations would be the same as with an isolator.

Happy New Year!

Kind Regards, John