3 Phase supply calcs.

[dlt27]

Looking in the panel it says cn range so on square D sheet looks like 0.09. Really appreciate it. Is amtech worth the money. Thanks

 

[dlt27]

What fee? Thanks

 

[Darkwood]

Hi - dlt27

It would help us greatly if you can show us your calcs and the cable sizes you end up with, we can then point out any errors or add further queries for you to answer or hopefully confirm they are correct. Its asking a little beyond our kind nature for us to do it all for you and provide the design although if any member wishes to then that's fine, if we can give us some idea here what you have come up and how then we are more than happy to help.

Things to consider -
- Discrimination between devices.
- What distribution system you wish to install be it a busbar setup or Powerboard.
- Will the installation require corrective measures for the welding equipment (Power Factor Correction).
- Bonding if your running into other factory units.

 

[dlt27]

I will go through it and put it on here tomorrow.
I wanted someone to go through process rather than do exact calculation. Thanks

 

[Darkwood]

I will go through it and put it on here tomorrow.
I wanted someone to go through process rather than do exact calculation. Thanks

Appreciate that, just trying to make the thread more concise otherwise it becomes a lengthy question and answer thread, if your using MCCB's against final distribution mcb boards then for full discrimination you will probably need an upstream device covering it of 160amp, if I recall to cover this 160amp device you would need a 400amp for full discrim' ... who has specified the 250amp?
Can you just draft a little block sketch of the proposed submains and circuits so we can better visualise your set-up.

 

[Leesparkykent]

Quick smoke packet calculation if the Ze is 0.05 and the manufacturer gives a max Zs of 0.09 at 100% your design max Zs is 0.075ohms at 80% to allow for conductor operating temp. Over a distance of 80meters a 185mm CPC would bring you just in under this value by a gnats cock. 120mm 4 core SWA based on 250A and 80 meter run will give you a volt drop of approximately 6.6V.

Using 35mm SWA from this panel board for the 30 meter 100A supply to the 3phase DB will give you a calculated volt drop of around 8.8V added to the 6.6V that's 15.4V In reality the total volt drop is going to be under this as it wont be pulling full load current and at 250A the cable isn't at its maximum CCC so wont be at maximum conductor temp at which the figures are based. With a 25mm CPC that would give you a calculated Zs/Zdb of around 0.12ohms which should be under the max permitted for a 100A OCPD.

The above is rough and vague but should hopefully point you in the right direction for your own calcs.

 

[jackhammerJIM]

does the factory have its own substation/transformer ?

 

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