My last 'non Amd 3' CU Install. | Page 15 | on ElectriciansForums

Discuss My last 'non Amd 3' CU Install. in the UK Electrical Forum area at ElectriciansForums.net

Dave OCD

-
Mentor
Esteemed
Arms
Joined
May 5, 2015
Messages
4,158
Reaction score
7,261
Location
Cornwall
Put this in today, I hope it doesn't burst into flames.:tongue3: Didn't have the time to faff about and get the cabling 'perfect' as I had so much to do today but I think it's ok. With the BG boards I generally 're number' the earth bar as to me it's illogical having the CPCs running in the opposite order of the neutrals,I'll miss the insulated CUs. Sorry about the
poor photo. :)
[ElectriciansForums.net] My last 'non Amd 3' CU Install.
 
At that particular point in time it dropped down to a coil sitting on the workbench below the board ;)
The supply board is immediately to the left of this one and the cable now does a neatish loop up to it. I think it's cable tied to the upright scaffold to the left (which is the structure of the workbench and mezzanine above)

As I said its our workbench so didn't exactly get tip-top tidying

Well at least your honest lol, seriously it just goes to prove we can all put pieces up for all to see, everyone of us will have our own opinions on what is great, okay, rough etc, but the point I am getting at is situations, we don't know them all, you pointed out your own with the workbench.
 
The first job I did as a self employed spark was 4 of the previous version of the above dimmer and a complete rewire of all outgoing circuits, I'm not sure if I've got any pictures of it in progress but this is the finished article.
Each one is fed with 80A TP allowing the install to dim 96x2.4KW channels simultaneously.

[ElectriciansForums.net] My last 'non Amd 3' CU Install.
[ElectriciansForums.net] My last 'non Amd 3' CU Install.
 
Well with an all RCBO board [of which I've installed quite a few] I always leave spare ways. Now can you post up a picture of one of your CU installs which I'm sure will be absolutely perfect ? But you never know,I might be able to make pointless negative observations if I can be bothered. Merry Christmas.



Wasnt having a go at the standard of your work, because in all honesty the job yo've shown is neat.

However, if you dont like leaving an unprotected way in a dual CU because a DiYer may add a shower, then surely if you left a spare way in an all RCBO board the same DIYer ciuld also add a shower, without the alll important RCD protection couldn't they?

Thats all ivwas saying.
 
I'd query whether the piranha nut on the incoming supply has the locking screw in place, seeing as it's done up onto a plastic enclosure. (May be out of sight.)

Thanks, I also hadn't spotted that, I'll fix it for them when we go to finish off.

At the other end of the supply the have just fitted piranha nuts and relied on the teeth biting into the metal enclosure to make the connection, which is something I'm in two minds about at the moment.

[ElectriciansForums.net] My last 'non Amd 3' CU Install.
 
Thanks, I also hadn't spotted that, I'll fix it for them when we go to finish off.

At the other end of the supply the have just fitted piranha nuts and relied on the teeth biting into the metal enclosure to make the connection, which is something I'm in two minds about at the moment.

I'm happy to rely on the teeth biting into the metal enclosure and don't even think that the locking screw is required in this situation if done up nice and snug. This is provided that the cable is properly cleated to eliminate movement and that it's a dry environment, so corrosion at the interface is unlikely.

Here's one I did last week. Continuity between gland and earth bar was confirmed (and actually there's a separate cpc in the cable anyway).

[ElectriciansForums.net] My last 'non Amd 3' CU Install.


Should raise a couple of other issues, but I don't care!
 
As far as I can remember the manufacturers instructions stipulate that the grub screw be tightened whatever.

The one issue that I'd pull it up on is the wrong cores being used for N and E.
Yellow (which is now black) has always been used for earth
Blue (which is now grey) has always been used for neutral
 
As far as I can remember the manufacturers instructions stipulate that the grub screw be tightened whatever.

The one issue that I'd pull it up on is the wrong cores being used for N and E.
Yellow (which is now black) has always been used for earth
Blue (which is now grey) has always been used for neutral


See, I said that the pic would raise issues. :D

You may be right about the manufacturer's instructions, but my judgement is that a tight metal to metal joint like that, not subject to vibration or movement, is perfectly OK. After all, everyone's happy with the usual thin nut provided with gland kits, which has no additional locking. I regard the locking screw as only essential where a plastic enclosure forms part of the 'sandwich' which may creep and result in a loose joint.

As far as the cable colours go, yellow may always have been used for earth and blue for neutral (which is now history), but the regs allow me to sleeve black with blue and grey with green/yellow, so I choose to do this (despite what the NICEIC or others may stipulate). If I was installing or extending a three phase cable then, of course, I would comply with Table 51 and Appendix 7 of the BYB.
 
My concern is the csa of just the points of the teeth making contact, what will happen under fault conditions? In the case of the fuse switch I posted above the incoming side is connected to the 200A busbar so will have an appreciable fault current available.

Blue and yellow are not history, they are still present in many installations.
If you extend a 3 core cable of any type would you join blue to grey and yellow to black?
What about the convention of using the L1 core for live, L2 core for sw live and L3 core for neutral?
 
My concern is the csa of just the points of the teeth making contact, what will happen under fault conditions? In the case of the fuse switch I posted above the incoming side is connected to the 200A busbar so will have an appreciable fault current available.

I think that the points of the teeth on the brass nut will be somewhat flattened and biting tightly into the steel of the enclosure. I recon the joint will be as good as the usual banjo, which will only be making metal-to-metal contact in places if looked at at a microscopic level anyway.


Blue and yellow are not history, they are still present in many installations.
If you extend a 3 core cable of any type would you join blue to grey and yellow to black?

If three phase, I follow the regs, L1 brown, L2 black, L3 grey. If working to a design, I'd follow the drawings. If single phase and my own job, I make my own decisions. Unfortunately, the IET haven't seen fit to define what the colour allocation should be when using bn/bk/gy cable in single phase applications. Maybe they should have.

What about the convention of using the L1 core for live, L2 core for sw live and L3 core for neutral?

When they were red, yellow and blue, it made some sense. Moving to brown black and grey....
 
Last edited:

Reply to My last 'non Amd 3' CU Install. in the UK Electrical Forum area at ElectriciansForums.net

News and Offers from Sponsors

  • Article
As the holiday season approaches, PCBWay is thrilled to announce their Christmas & New Year Promotions! Whether you’re an engineer or an...
Replies
0
Views
558
  • Article
Bloody Hell! Wishing you a speedy recovery and hope (if) anyone else involved is ok. Ivan
    • Friendly
    • Like
Replies
13
Views
993
  • Article
Join us at electronica 2024 in Munich! Since 1964, electronica has been the premier event for technology enthusiasts and industry professionals...
    • Like
Replies
0
Views
924

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top