Parallel Supplies

[Guest 004]

Is there amything wrong with having a parallel supply, that will consist of 2 different size cables?

for examples say cable 1 = 25mm, cable 2 = 10mm.

To give a 35mm

 

[SPARTYKUS]

If you're on a Naval ship, at war in the middle of the sea and having to make do with whats available right now, then yes.

What is the context Mr Enigma?

 

[Guest 004]

my client wants to save money.

I have calculated that he needs a 35mm supply. He already has a 25mm supply, the run is 100m.

 

[telectrix]

433.4, 523.1, 523.7, and appx. 10. happy reading.

 

[SPARTYKUS]

I can't think of a regulation to quote you why its a bad idea, just feels bad.

For instance if you have two runs supplying the ... Supplied thing, and at a
later date one cable of the two is damaged / disconnected ..... Well then the other one may become overloaded without anyone noticing

 

[telectrix]

that could happen even if both cables were equal size.

if he insists on parallel conductors, at least run in another 25mm. then you'll have some extra capacity for future increase in loading.

 

[SPARTYKUS]

that could happen even if both cables were equal size.

Agreed

 

[kingeri]

My BGB is in the car but from memory I thought the cables would have to follow the same route and be the same CSA.....but I may well be wrong.

 

[Guest 004]

was thinking to use same size, and of course they will follow the same route, which wiould be in a duct in the ground. So good protection.

 

[Knobhead]

Sorry kid, both to be the same size and same route.

 

[SPARTYKUS]

50mm squared it is then!! You can up the demand

 

[Knobhead]

It doesn't work like that two 25s equal more that the CCC of a single 50. I know they are a pain but they work out better than a single cable.

 

[Guest 004]

2 x 25mm it is then.

Wonder what the CCC would be then?

 

[SPARTYKUS]

Im guessing (Tony) that it works out better because of better dissipation of heat maybe, as theres more surface area free to ... Dissipate?

 

[telectrix]

Im guessing (Tony) that it works out better because of better dissipation of heat maybe, as theres more surface area free to ... Dissipate?

i'll agree with that.

 

[Guest55]

twin / parallel feeds are pretty common on submains larger than 300mm.

struggling to think of anything else to add to be honest lol.

er , carry on.

;-)

 

[SPARTYKUS]

As you were, carry on. At ease?

 

[telectrix]

As you were, carry on. At ease?

it's sunday, stand easy.

 

[SPARTYKUS]

Defcon 2.

 

[telectrix]

def beer!!!

- - - Updated - - -

defcon beer!!!

 

[Guest 004]

ok kronenberg it is

 

[SPARTYKUS]

I'll take a jug of San Miguel.

 

[Guest 004]

true sparkies get on the ****!!

 

[telectrix]

I'll take a jug of San Miguel.

bloody girlie lager. be a man and get some theakston's down your neck.

 

[SPARTYKUS]

Jennings Snecklifters my favourite. It doesnt lift the sneck.

 

[Spoon]

hoo hoo Can I join in this thread?? I'll invite Eng54 as well...

 

[Engineer54]

Parallel circuit/supply needs all conductors to be of the same CSA, follow the same route, cables be of the same type and construction. Parallel circuits can consist of several conductors/cables not just two. Such circuits can and do offer many advantages over a single much larger conductor/cable installation....

If designing the OP's circuit from scratch probably 2 X 16mm would be selected, but in some circumstances even 2 x 10mm could replace a single 35mm cable....

 

[telectrix]

so, in a nutcase, sorry, nutshell, as OP already has a single 25mm, the solution is to parallel a second 25mm cable in.

 

[SPARTYKUS]

Don't spoil it prematurely Tel

 

[telectrix]

i already said it in post #6.