New 3phase supply?

[chrisbyrd]

Hi Guys

I have a requirement to upgrade the power supply in a light industrial unit

The current supply appears to be a basic 100a single phase supply.

When the building is full we will have a usage of 1200a 'single phase' - ie, 150 lots of 8amps after 3phase has been split down

I've been trying to do my homework, but all this 3 phase stuff is slightly over my head at the moment.

is that 400amps of 3phase usage?

what sorts of things are involved in getting a supply like this into a building? the electricity company havent been particuarly useful so far.

do we need substation\transformer?

who sorts that out, the electricity network company or do we arrange that?

2 out of the other 5 units on the same area seem to have an EDF substation outside, so I guess the main cables cant be too far away

can anyone give me any pointers about where to start with this? and a rough idea of what sort of budget we should set aside for this part of the project?

Thanks all

(pls forgive my ignorance!)

 

[Spark123]

Is it 3phase day today or something?

In a nutshell, a 3phase 400A incomer will give you 1200A to play with in terms of single phase. Thats a lot of electric!! The only people I can see being able to answer the rest of your questions will be your distribution network operator (DNO).

 

[Steve]

what will the unit be used for?

what do you mean by 150 lots of 8 amps? yes it comes to 1200a, but why this way of putting it?

 

[ricicle]

Chris,
This sounds like a major job which is beyond the scope of a diy forum because the nature of these loads needs to be taken into account.Are they all single phase.Are the currents you quote including any power factor.Is there any diversity on these loads (ie are they all to be on at the same time or are they intermittent)Depending on the size and/or number of local? transformers depends on whether there is any capacity for the supply authority to supply you and how much are you willing to spend if they need to upgrade their supplies if the figures you quote are correct.Hopefully this shows why it would be impossible to give any figure for this.Remember you will also need add all your other demands to this also (heating,lighting etc)

Ricicle

 

[chrisbyrd]

Thanks guys

Don't worry - dont indend DIY'ing this - i was more looking to be pointed in the right direction and noticed there were a few 3phase related threads

In answer to the earlier question, we are looking to kit out a light industrial unit and fill it with 100 - 150 computer racks with around 8 amps of computer equipment in each (all on constantly).

This is all be single phase, I believe the air con system may be 3 phase however

We have the UPS and climate control systems just about lined up, but I've been tasked with finding out the direction to head in for pricing up whats required for mains power input

 

[Pensdown]

Since privatisation, supply up-grades are a nightmare. If I were you I would appoint an electrical contractor/consultant and let them sort it out for you.

You will need around 600kVA (around 800amps/phase) which will give you 400amps/phase for your cabs and 400amps/phase for your AC, lighting and small power.

To get a price from EDF will need a contract with a supplier i.e npower, british gas etc. Once you have a contract they will give you a reference number to pass on to EDF. EDF will then raise a project and give you a quote which can take up to 3 months, yep, 3 months. Once you've approved the quote and paid in advance the works will not be started for another 2-3 months.

Good luck

 

[plugwash]

remember to add in the overhead of the UPS system as well, when mains comes back after a power cut there will be significant extra load as the thing recharges. You will need to check with the UPS manufacturer just how much this will be.

you will also need to consider the power demand of the air conditioning, all the heat those computer racks put out will have to go somewhere! You will probablly wan't to consider backup power for the air conditioning too as you won't be able to keep running very long without it! I'd imagine lighting will be pretty trivial by comparision and heating probablly won't be nessacery .

calculate the requirements including UPS and aircon overhead, add at least 25% possiblly more for expansion and things you haven't thought of and then write a letter to the electricity supplier stating what power you need and asking what your options are.

this will NOT be a cheap job!