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New three phase wiring. Advice needed

Sameer Sher
Hi,
Need some advise on a new three phase wiring.. Thanks in advance..
 
It's a small commercial bakery. They have got a new 3 phase power supply of 200A. The bakery has few three phase machines. Of them are two heavy load ovens and rest are light. One oven takes 80 amps per phase and other 100 amps(these machines will be have to be connected through 25mm SWA cable due to load. Also we will have to install fused isolators near the machine say 100A each to operate) The client won't be running the two machines at one go so the supplied amps of 200A should be enough.
The task now in hand is to connect these machines to supply. I was thinking of few different ways but not sure if it's right
1) one way would be to get a switched MCCB 6 way panel board say with 250A incomer. Distribute the panel into three using MCB- 100A for machine 1, 100A for machine 2 and 100A for distribution board(which will have all other machines, lights etc connected through circuit breakers)
2) Second way would if I can get a heavy load distribution board say 18 way, 250A and connect the machines all in this board. But am confused if I will be able to connect the 25mm SWA to machines in this DB on a 125A MCB. 
These are two ways I was thinking. Please let me know how to proceed and also if there is some other way, please advice.
Thank you again for your time
  • 0

    I think the MCCB panel or BS88 s fused isolators are your only option - I doubt you'd get bigger than a 63Amp MCB for a 250A Distribuion board. 

    Perhaps go MCCB panel board - SWA - to a metal clad 3 phase appropriately sized Isolator - into which the oven is connected. A commando socket is also a possibility. An isolator is cheaper than a fused isolator. You can rely on the MCCB in the MCCB panel for overload protection. 

  • 0

    Look at Hager Hybrid Boards. 250A rated MCB board with 2 x 125A 3 phase large frame MCB' ways. This way you don't need  separate board for all your small stuff like you would with MCCB's 

  • 0

    If you wanted to have a more conventional consumer unit look, then DIN rail 125 amp 3 phase MCBs are a thing (eaton, chint Schneider Hagar etc all do them) but you may not want to use much else on the bus-bar if you have 2 in a box.

    125A breaker

    https://www.cef.co.uk/catalogue/products/search?q=mcb&current_rating[]=125A

    is an example.

    200A or 250 A type B box.

    https://www.cef.co.uk/catalogue/categories/mcb-distribution-boards-tpn-distribution-board?current_rating[]=250A&current_rating[]=200A

    The small boxes are only a few hundred quid, but set aside as much money again for the main switch on one of those though.

    Mike

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