what size of cable will i need for pizza oven, 3 Phase MCB?

[bongos]

He is a qualified electrician tho...

 

[ban-all-sheds]

well i have just qualified as an electrician,but havent had enough experience in domestic wiring

Or commercial/industrial, by the looks of it.

Kevin - when you said you had just qualified, what exactly did you mean? What qualification(s) did you get?

 

[ColJack]

Not going to make a huge difference though is it!

Atleast it is not tens of amps out which it would be if you had originally designed the circuit

my error was to oversize the cable, and too big is better than too small....
The TLC calculator came back with the same current and cable size as I originally got..
when I put in 4C PVC SWA and 400V 40m..
if I put in 230V, same everything else, it told me there was no suitable cable..
so I'm guessing that the TLC calulator is wrong too..

 

[RF Lighting]

He is a qualified electrician tho...

Qualified maybe, but competent??

 

[ColJack]

you had me doubting myself.. but the 3phase 18.5KW motors where I used to work are have 45A stamped on the rating plate.. and are wired in 10mm cable..
that's why my calculation sounded right to me..

 

[ban-all-sheds]

Yup.

18500W @ 415V = 45A.

But not 45A per phase any more than it's 415V per phase...

 

[kevin1234]

so is it 45 amps or 27amps per phase then?

 

[kevin1234]

that's the problem with using 230 and 400 though..
230 x sqrt3 = 398.37V..

so depending on the method you use you get a different answer..

power / (3 x Vphase ) = 18500 / (3x230) = 26.81A..
power / (sqrt3 x Vline ) = 18500/ (sqrt3 x 400 ) = 26.70A..

so is it 26.81 or 46.25 amps?

 

[Lectrician]

Would your customer be happy to know you have to resort to asking these questions on a forum?

Is that what they pay you for?

 

[kevin1234]

Would your customer be happy to know you have to resort to asking these questions on a forum?

Is that what they pay you for?

jesus christ what is it with people these days!! I know im only qualified and all! but how is anybody supposed to get experience when everybody just thinks you should know everything!!

So can anybody give me the answer?

 

[RF Lighting]

i am only enquirying i aint planning on doing anything

Oh, so you were lying to us then

 

[kevin1234]

All you's ever do on here is moan at people for not knowing the answer!! you all expect everyone to have 15 years experience behind them n know everything!!

You forget about the others who are only just qualified, and cant get any work, and are trying there best to get experience!

so could anyone answer my question?

 

[RF Lighting]

You are a danger to your customers and should not be doing this work.

I know you just want a simple answer, but that is not going to happen.

You are installing electrical circuits for a living, so the least you could do is actually make the effort to learn how to properly design and install circuits your self, rather than just guessing at it like you do now.

 

[kevin1234]

You are a danger to your customers and should not be doing this work.

I know you just want a simple answer, but that is not going to happen.

You are installing electrical circuits for a living, so the least you could do is actually make the effort to learn how to properly design and install circuits your self, rather than just guessing at it like you do now.

well how else am i supposed to learn when people wont help and understand that they were once upon a time in the same place i am just now, as i keep saying i want to learn, but cant get the experience as there is no work! so im trying my best to learn!

anybody help!

 

[Lectrician]

If you want to learn - go google, or better still, sign up to a course.

Asking us for an asnwer is not the way.

You have been given two sets of workings. One is correct and one is incorrect. Try googling 3 phase power and see what you find.