Using 7 Core Armoured as Twin and Earth ?

[keithy1959]

Pete - will do - I was struggling to explain it in words !!

I'm back up there tomorrow, so I'll try and sketch it as much as I can, but I suspect the 7 core is connected to the house wiring, somehere under a tiled (suspended ) floor.

 

[MDJ]

This doesn't sound right to me .

Can I ask why?

 

[Deleted account]

Makes no difference providing they are equal cross sectional area.

Obviously in this case they are equal cross sectional areas, but why must they be.

I can understand it would make design easier, but not sure of the specific reasoning.

Cheers

 

[Risteard]

looks to be 1m2 or possible 1.5m2.

You'll struggle getting such a large conductor into the terminals...

 

[westward10]

Obviously in this case they are equal cross sectional areas, but why must they be.

I can understand it would make design easier, but not sure of the specific reasoning.

Cheers

If they are the same csa the resistance is equal so the load is balanced across the two. Differing csa will result in an imbalance across the two.

 

[Deleted account]

If they are the same csa the resistance is equal so the load is balanced across the two. Differing csa will result in an imbalance across the two.

Trying to get my head round this and not disagreeing, just like to know the ins and outs of stuff.

Does the resistance need to be equal as it's the overal resistance and csa that the current would be traveling.

Wouldnt the current be greater down the larger conductor than the smaller?
Due to current traveling down the path of least resistance would it would balance itself out proportionately between conductors.

 

[Spoon]

With reference to @westward10 post above:

 

[keithy1959]

Can I ask why?

Out of ignorance, perhaps. I know the math (area) is OK, but it seems a bit like making a ring circuit from the wrong cable - I appreciate the correct breaker would fix that, but I was interested from a good practice point of view.

From an installation point of view, the house is on a 1 in 3 slope, with the garage floor roughly level with the bedroom ceilings, so replacing the cable is going to be a pain. I guess I'm just checking this wasnt a "just enough" solution to save the grief.

 

[Octopus]

Pete - will do - I was struggling to explain it in words !!

I'm back up there tomorrow, so I'll try and sketch it as much as I can, but I suspect the 7 core is connected to the house wiring, somewhere under a tiled (suspended ) floor.

Not wishing to state the obvious but doubling up may only be possible if you can locate the connections ........ at both ends

 

[keithy1959]

You'll struggle getting such a large conductor into the terminals...

The truly sad thing is, it took me a few re-reads before it dawned on me what you were implying

 

[keithy1959]

Not wishing to state the obvious but doubling up may only be possible if you can locate the connections ........ at both ends

Absolutely !! I imagine that ultimately there will be some serious "re-organisation", so we will see. It's one of those houses where nothing is simple

 

[Toneyz]

What is the SWA connected to in the house?

 

[keithy1959]

The various cables provide supply to a single socket in the garage, the two way switching and supply for the outside light that is paired with one on the house wall, and the power to the garage light. They are stranded cables, and I dont know enough to say if they are 1mm3 or 1.5

The SWA goes all the way back to the consumer unit, and appears to be connected into the ground floor lighting circuit for lights and a 16a fuse for the Socket.

They have decided to leave all alone for the time being, and tidy it up when they have the consumer unit replaced in the New Year. As they have long term plans to turn the garage into a games room, we (ie Daddy) will probably get a new 6mm SWA run up at the same time as the CU is done.

I have put an RCD plug / double socket up there for the time being with 500Watts Max written all over it - just in case !!

Thanks for all your advice on this.

Keithy