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Speculative Warehouse - LV Distribution

fiftyhertz
Hi all,


I’m looking at a large warehouse for a developer who is building a large unit speculatively. The allowance required is approx 550KVA, or just under 800A per phase. The will need an integral DNO sub with a designated outgoing feeder. The unit is to be fit out by others, other than an office area. 


This brings me to my question, how do I supply the offices with a small TP&N DB without getting the client to pay for a highly rated LV Switchpanel which will likely be stripped out? Or is it normal for the Developer to provide an LV Switchpanel?


My idea so far is to bring fully rated TX tails (which the future tenant can reuse) into an MCCB/ACB and from there supply a 800A busbar chamber with can then supply the small DB. 


Has anyone done something like this before?


thanks in advance
  • 0
    At the risk of misunderstanding the question, is this really a matter of a high PSCC making what sounds like it may have been a box with half a dozen MCBs or RCBOs more expensive ? (In which case the answer could be something like a DNO service head fuse as an energy limiting element)

    The offices will need the normal commercial arrangements of final circuits protected by RCD or RCBO, Do they need sub-metering?

    Or is the question, how can we make this cheaper as it is only temporary ?  I'd suggest you should not  try too hard- the desks, carpets and IT equipment in the office will still be full price (maybe even rented desks, depending on the duration.) Those costs will dwarf the electrical installation.

    M.
  • 0
    Is this supply for the single warehouse or more than one?


    If for one then a fully rated supply in to a panel board fitted with 2 MCCBs with spare ways.  


    One MCCB to supply your office space. One to supply a DB in the warehouse. The usual arrangement is to have a big empty DB in the warehouse with a socket adjacent to the DB and a single luminary above the DB. Left for the new occupier to fit out.


    The developer usually installs the supply to the warehouse and arranges for the supply to be connected and metering. 


    Need a bit more information to be sure of your question?
  • 0
    John,


    Firstly Thankyou for the reply, I have watched several of your IET webinars and they have all been great.


    I wasn’t sure this was usual practise, but it definitely makes sense as the major infrastructure works would be left to the tenant, and this doesn’t seem right as they don’t own the building. I will propose this going forward AWA singles from the TX LV Panel terminated into an MCCB which will supply a panel board with outgoing submains.


    Two follow up questions if you don’t mind. 

    1) The unit is a single warehouse, although smaller ones are being installed adjacent (not attached). My plan is to take them off the DNO sub as typical supplies into an ISU etc so they are separately metered, If there was more than one (for future reference) what would be your approach? Perhaps a BEMCO unit as per Private Resi?

    2) If the supply was above 800A, a freestanding Schneider Powerpact 4 unit would be required, which goes upto 1600A. When would you specify a custom LV Switchboard instead of a panel board. My assumptions would be where a greater form would be required ie form 4b type 3 etc. Or when the supply goes above 1600A. Does this sound reasonable?


    Thanks
  • 0
    Thanks for the feedback on the webinars, I have another 2 in the pipeline that I have target dates for.


    Difficult to say what to do on your job. Often these premises command higher 

    rent if they have they have plenty of power available. They get used as factories with power hungry processes. 


    If if you have a number of units to supply then I would be engaging with the developer or owners on how they want the available power distributed. Then supply an MCCB Form 4 panel from the Tx and then an un-metered BNO suppply to each unit to 3 phase head fitted with solid link Red Heads, meter and big 3 phase DB. I would be getting input from my client as to what they want before putting finger to keyboard to carry out my design.

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