Industrial unit power supply requirements

[Welderpaul]

I'm trying to get a feel for power requirements on a 5000 sq ft newish industrial unit - I'm told available 3 phase supply is 50KVA. Doesn't sound much to me for a unit of that size?

Potentially one of the main bits of kit tips up at 35kva leaving 15kva capacity when it's running. I had a quick google of a Lorch S8 welder as an idea of what load they pull and the nearest info I can find (generator load) is 15KVA.

Have I got the right end of the stick with how this works or is it likely to be 50KVA per phase?

 

[TryingToWeld]

I would ask for clarification, but would assume its per phase, which would give approx. 200A per phase.

You need to deduct anything that will be running all or most of the time, (electric heaters, lighting, machines etc.). That'll leave you with an estimate of your spare capacity for kettles, etc.

It's a reasonable supply, but I bet upgrading it would be expensive, so if you think you're going to need more get a written quote before signing anything!

 

[Misterg]

is it likely to be 50KVA per phase?

Check, but I think it would be 50 kVA total (70A / phase).

If you need more (and the incoming switchgear will take it), speak to the DNO - they may have spare capacity to allocate without any need for hardware changes.

Generally there will be a certain capacity available in total for a group of units, and it depends what capacity the others have asked for as to what's still available. If your request takes it over the top, they'll want to bill you for upgrading the whole shebang!

 

[Dave-sparks]

If it's described as a 50kVA supply then that is 50kVA total capacity, supplies are not described as 'per phase'.

Get written confirmation of the supply details then take it from there.
And get someone experienced who knows how to work out your power requirements to look over things for you, just adding up the total power requirements of all equipment could lead to you spending a lot of money on a supply you don't actually need.

What is the nature of the 35kVA load? Is it one big motor drawing 35kVA or is it a machine with lots of parts which total 35kVA when added up but are never actually all on at once?

 

[Dave-sparks]

Are you moving an existing business setup into this unit?
If so you could have a loaf study carried out for a couple of weeks on the existing setup to find out what you are using now.

 

[knighty]

when ordered 3 phase put in at home (they're still working on it) I asked for 100 amps per phase... that was £5000..... but I'm only paying for the connection from the telegraph pole to my meter - they said the local network couldn't support it, so they're changing the supply to the local transformer from 11kv to 22kv, fitting a new transformer, running new cables from the sub station along all the telegraph poles to our house - and replacing a load of the old telegraph poles.... they're paying for all that not us

at work we had a 400amp/phase supply put in (upgrading from 100amp) it was £10,000 to run it from the path on the other side of the road, under the road, under our path and into the front of our building


obviously I wish it was cheaper... but at the same time it's not the insane prices you sometimes hear about

 

[addjunkie]

when ordered 3 phase put in at home (they're still working on it) I asked for 100 amps per phase... that was £5000..... but I'm only paying for the connection from the telegraph pole to my meter - they said the local network couldn't support it, so they're changing the supply to the local transformer from 11kv to 22kv, fitting a new transformer, running new cables from the sub station along all the telegraph poles to our house - and replacing a load of the old telegraph poles.... they're paying for all that not us

at work we had a 400amp/phase supply put in (upgrading from 100amp) it was £10,000 to run it from the path on the other side of the road, under the road, under our path and into the front of our building


obviously I wish it was cheaper... but at the same time it's not the insane prices you sometimes hear about

Id have happily paid 5k to have 3 phase power. I was quoted 22k, as it required a transformer etc from the main line.

 

[Moose McAlpine]

Id have happily paid 5k to have 3 phase power. I was quoted 22k, as it required a transformer etc from the main line.

My neighbour paid ~20k to have 3 phase run into his house.

 

[indykid]

My neighbour paid ~20k to have 3 phase run into his house.

We're first house on the street and turns out we've always had 3 phase to the cut out. I was only made aware when they had to change the cut out because the old one was asbestos lined - it hadn't occurred to me that the cast iron enclosure was that big because it had 3 fuse locations in it.

 

[SipMerlin150]

Hello, i think you may have around 70A per phase supply, you could always ask the DNO for an upgrade, but the power goes further than you think, most industrial appliances are rated for its worst case scenario like inductive power surge which typically is found in inductive loads like large motors, welders, etc. once up and running they tend to draw less current. Whats more important is to balance the loads across all 3 phases as equal as possible to prevent any of the phases from drawing more current to compensate.

Where i work is 17,500 square foot and is on a 150A supply, this powers 11 welding sets, 4 overhead cranes ranging from 2 ton up to 10 ton, the office computers/servers, quite a number of electric heaters, 2 large heater blowers, and a couple of high speed EV chargers. Now each welding set has a total of 28A draw so lets say 28A x 11 would be 308A in total, double what we are fused to at the board. Now because the inductive load draw only lasts for milliseconds, the breakers won't trip. Never had a overload or a trip in the 9 years of my employment there. Hope this info helps you along

 

[GaryS65]

when ordered 3 phase put in at home (they're still working on it) I asked for 100 amps per phase... that was £5000..... but I'm only paying for the connection from the telegraph pole to my meter - they said the local network couldn't support it, so they're changing the supply to the local transformer from 11kv to 22kv, fitting a new transformer, running new cables from the sub station along all the telegraph poles to our house - and replacing a load of the old telegraph poles.... they're paying for all that not us

at work we had a 400amp/phase supply put in (upgrading from 100amp) it was £10,000 to run it from the path on the other side of the road, under the road, under our path and into the front of our building


obviously I wish it was cheaper... but at the same time it's not the insane prices you sometimes hear about

Friend just been quoted 40k for a 60A supply

 

[Hitch]

The unit we are setting up at the moment, about 1600m2, has a 200a 3p supply. Partly it has been built to our spec.

Looking at conversion tables, that's about 166kva.

Running the usual, press, guilty, ohc, welders etc

 

[Barking Mat]

Think I paid €500 to get three phase installed in my old house.

(In France).

 

[anto44]

I'm in Ireland and was given an estimate of €240,000 to have 3 phase installed here

 

[Kayos]

I've sent @Welderpaul a PM

Regarding 3 phase, I have seen quotes ranging from £2k to £800k (new substation and network upgrades)

You cannot compare costs as every application is based on a specific network study, and busy places can be a rapidly evolving situation

 

[Barking Mat]

Last time I bought a house, I counted the wires going to it, four is what your looking for.

Three phase is very handy, all my welding, cutting and machining tools are three phase.

 

[8ob]

Three phase supplies can be a lot cheaper if you leave the meter at the boundary and run in your own sub mains, we are doing one atm which is 260mts. That would probably run into tens of thousands if th client had them run the mains into the property.

Bob

 

[Kayos]

Three phase supplies can be a lot cheaper if you leave the meter at the boundary and run in your own sub mains, we are doing one atm which is 260mts. That would probably run into tens of thousands if th client had them run the mains into the property.

Bob

Otherwise known as contestable work.

I've a small solar farm on the go at present, we have actually got a no works DNO upgrade because the client is sorting all the cables etc, just need a £250 witness test

Better than the £30k initial DNO quote