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

[Lectrician]

you were right the first time oharaf.. for 230V it's
P/(3x230)


so 26.8A..

so why is this right! and not the other one then could somebody explain?!?

Because the other way was incorrect.

Do you know how to convert Kw into Amps? Do you understand the differences between three phase and single phase? Do you understand about single phase loads connected to three phase supplies?

 

[ColJack]

you were right the first time oharaf.. for 230V it's
P/(3x230)


so 26.8A..

so why is this right! and not the other one then could somebody explain?!

I made a mistake with the first answer I gave because I used the phase voltage and not the line voltage..

the phase voltage is each phase to neutral ie. 230V.
the line voltage is phase to phase ie 400V.

amps per phase is either..
P/(3 x phase voltage)

or

P/(sqrt3 x line voltage)

 

[kevin1234]

you were right the first time oharaf.. for 230V it's
P/(3x230)


so 26.8A..

so why is this right! and not the other one then could somebody explain?!?

Because the other way was incorrect.

Do you know how to convert Kw into Amps? Do you understand the differences between three phase and single phase? Do you understand about single phase loads connected to three phase supplies?

well not really could you explain?

 

[electronicsuk]

you were right the first time oharaf.. for 230V it's
P/(3x230)


so 26.8A..

so why is this right! and not the other one then could somebody explain?!?

Because the other way was incorrect.

Do you know how to convert Kw into Amps? Do you understand the differences between three phase and single phase? Do you understand about single phase loads connected to three phase supplies?

well not really could you explain?

You are just having a laugh now... (except it's not all that funny)

EDIT: Woo! Nested quotes!

 

[kevin1234]

you were right the first time oharaf.. for 230V it's
P/(3x230)


so 26.8A..

so why is this right! and not the other one then could somebody explain?!?

Because the other way was incorrect.

Do you know how to convert Kw into Amps? Do you understand the differences between three phase and single phase? Do you understand about single phase loads connected to three phase supplies?

well not really could you explain?

 

[Lectrician]

To be honest - no. It takes a long time to train as a spark, and these are the basics.

What course did you do to become qualified, and when did you do it?

Can you convert Kw to amps? How many amps does a single phase 12Kw load take?

 

[kevin1234]

To be honest - no. It takes a long time to train as a spark, and these are the basics.

What course did you do to become qualified, and when did you do it?

Can you convert Kw to amps? How many amps does a single phase 12Kw load take?

i did a normal apprenticeship,

ye, you use P= v*i or i = P/V, to fine watts to amps is that right??

I=P/V, 12000/230= 52amps

is this right?

 

[ColJack]

Heating elements do not need a C curve, a B would likely be fine. There is no fans in pizza ovens.

but there may be a conveyor with a motor..

Most TP breakers will always come as 10kA.

quite likely, but class 3 equipment on 400/690V is 6kA MINIMUM.. according to the book..

I would hard wire it with a rotary isolator. It's neater. You can still move the pizza oven if you require.

If it's good enough for McDonalds kitchens, it's good enough for a pizza shop..

So, if you use a socket, do you RCD protect? That will get some brains working.

not for the socket itself.. but you might have to for the cable selected and the installation method..
the socket is more than 20A, or more than 32A and the pizza oven isn't for use outdoors.. ( I presume ).
the socket would be for the connection of a specific piece of equipment..

 

[ColJack]

website playing up.. made me double post..

 

[Lectrician]

You would not need to RCD protect a buried cable in a commercial application, especially if it s going to be done in SWA.

I am yet to see a pizza oven with a conveyor?

 

[RF Lighting]

Most TP breakers will always come as 10kA.

quite likely, but class 3 equipment on 400/690V is 6kA MINIMUM.. according to the book..

What's the line - line Ipsc at the DB?

 

[ColJack]

You would not need to RCD protect a buried cable in a commercial application

not true.. that rule applies to all installations, not just houses..

especially if it s going to be done in SWA.

we don't know that it will be done in SWA.. the client might want white surface plastic conduit and trunking.. ( which still wouldn't need RCD since it's surface but the point is we don't know the installation metod.. )

I am yet to see a pizza oven with a conveyor?

really? my pizza place uses one..

 

[ColJack]

Most TP breakers will always come as 10kA.

quite likely, but class 3 equipment on 400/690V is 6kA MINIMUM.. according to the book..

What's the line - line Ipsc at the DB?

my bad.. confusing impulse withstand and psc.. ( ones kV the others kA.. )

 

[ban-all-sheds]

I know im only qualified and all! but how is anybody supposed to get experience when everybody just thinks you should know everything!!

You're a qualified electrician.

Surely 3-phase theory and calculations were part of the course(s) you did to become a qualified electrician, not something that's a total mystery to you until you pick it up through experience?

All you's ever do on here is moan at people for not knowing the answer!!

Only when they really should. For example, if they were a qualified electrician and the answer was basic classroom stuff they would have done as part of becoming qualified.

so could anyone answer my question?

You're a qualified electrician - why don't you know the basics of 3-phase?

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!

You're a qualified electrician - you should already have learned this in class, and been tested on it in your exams - you know, the ones you passed that made you a qualified electrician.

If i was told how to calculate the size of the cable and the breaker needed i would be able to do it. but i am wanting to learn how to calculate it.

You're a qualified electrician - you were told how to do all that on your course.

well i cant see which one is wrong, could you tell me?

You're a qualified electrician - why can't you tell which is wrong on the basis of the knowledge you acquired on your course?

so why is this right! and not the other one then could somebody explain?!

You're a qualified electrician - why can't you explain on the basis of the knowledge you acquired on your course?

Do you know how to convert Kw into Amps? Do you understand the differences between three phase and single phase? Do you understand about single phase loads connected to three phase supplies?

well not really could you explain?

You're a qualified electrician and you don't know any of that?

How can that possibly be?

i did a normal apprenticeship,

That's not the answer to the question Lectrician (and I) asked you.

What course(s) did you do and what exam(s) did you pass?

What qualification(s) have you got?

ye, you use P= v*i or i = P/V, to fine watts to amps is that right??

I=P/V, 12000/230= 52amps

is this right?

You're a qualified electrician?

 

[briwire]

3 phase power =1.732xVxIxPF

where 1.732 = square root of 3
V assume to be 415
I is the current that you are looking for.
PF is the power factor which should be almost 1 in a near totally resistive load such as an oven.

18500=1.732x415xIx1

Transpose the formula to give I=18500/718.8

I=25.74A

I've not got the tables to hand but others have worked out the volt drop for 26A that length so I would say that 6mm sounds about right.