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Topic Title: ring final connection blocks
Topic Summary: connection blocks to make the ring
Created On: 11 July 2013 02:48 PM
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 11 July 2013 02:48 PM
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deleted_1_AngelLaHash

Posts: 39
Joined: 27 September 2012

Basically I'm putting in a Ring Final and Lighting in to the Sheds.
Gots own DB off a 40A and then 32A for the Sockets and 6A for the Lights.

The RING is KILLING ME, pulling it in to all that trunking with so many bends in it (i was daft but got to keep going) Can i stop the ring at one point and use Terminal Block so i can stop, and points then keep going around till i meet the next socket.

Also the Earth, its ok to tap off the Ring Earth to the Lights or do they need there own line, really it will be only one or the other using the earth when it shorts, not every thing at once going down it.

(note im dyslexic so being funny passes me by, cant read emotions in to Text)
Told I posted in wrong area
 11 July 2013 03:43 PM
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AJJewsbury

Posts: 11768
Joined: 13 August 2003

Sorry, but I can't quite picture what you're trying to describe. Is this just a typical domestic shed? What wiring system are you using? (T&E, singles in trunking? - or conduit?)

What are you trying to achieve using terminal blocks? - just install a cable length as two short lengths rather than one longer one? (I'm having difficulty seeing how any cable length in a shed will be so long as to be unmanageable - have I got the wrong end of the stick somewhere?) Yes, you can join cables using terminal blocks, but they'll need to be suitably enclosed & remain accessible.

It is permitted to share an earth between two or more circuits - typically done when using common metallic conduit or trunking as the c.p.c. - but has its disadvantages with other wiring methods (e.g. losing the ability to work on the socket circuit without loosing the lights at the same time). Again I'm having difficulty imagining the setup you might have in a shed where it's at all difficult for the lights to have their own c.p.c.s.

- Andy.
 11 July 2013 04:47 PM
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deleted_1_AngelLaHash

Posts: 39
Joined: 27 September 2012

i dont think forums are for me.. Sorry
 11 July 2013 04:55 PM
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AJJewsbury

Posts: 11768
Joined: 13 August 2003

Don't give up yet!

It is hard for everyone to describe things using just text in Forums like this. We can take it step-by-step if you like.

What sort of "shed" are we talking about? A wooden hut next to a house or something else?

- Andy.
 11 July 2013 05:09 PM
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deleted_1_AngelLaHash

Posts: 39
Joined: 27 September 2012

Brick Shed(s) Toilet - Washing Machine - Work Bench (Just fixing Electric Guitars)

40A Breaker from the MAIN DB - 4mm Cable to the Sub DB 32A for the Sockets and 6A for the Lights

Wanted 2.5 Live/Natural with 1.5 Earth going from a Socket in the Washing Machine Shed, then 3 Sockets in the Work Bench Shed
Going Via 20mm Plastic Conduit (not sure if i should of gone up to 25mm Really, but its what i got now)

Running all that 2.5 is hard work pulling it via all that conduit (Plus i brought the dam wrong one (Twin and Earth) really wanted Single Core to run in Conduit, but got to make do £££) So I wonder with Terminal Blocks at Stages so it makes easy on me.


There is also a 1.5 Lighting system for the Toilet and the Work Bench Shed (even side of the DB board.
I did wonder if I was ok to tap off the EARTH from the RING for the Lighting Earth (Metal Boxes on the Sockets and Light Switchs)
 11 July 2013 05:40 PM
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AJJewsbury

Posts: 11768
Joined: 13 August 2003

OK - I'm getting some the picture now.

2.5 T&E in 20mm conduit will be a tricky especially on long lengths or around bends. There are tables for length/number of bends, which it sounds like you've exceeded (I don't recall trying 2.5 T&E in 20mm conduit on anything other than straight lengths myself). Can you put some round conduit boxes in the conduit run to allow you to pull the cable through in stages? (but still leave the cable in one cut length between sockets). A bit of lubrication might help.

Is the lighting in T&E as well? If so you'll have an earth at each position anyway. Generally the c.p.c. needs to follow the live conductors of the same circuit and enter metal enclosures through the same hole(s) - so your scope for 'pinching' it from another circuit is limited.

BTW - your 4mm2 submain won't be protected from overload by the 40A MCB - at the moment it'll probably be OK by the 32A MCB and limited lighting circuit, but bear it in mind if there are any additions.

Do you have some 30mA RCD protection in there somewhere?

- Andy.
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