I have been told that I have a building that has a loading of 300 amps 3 phase (100 amps per phase). I am trying to figure out the loading in terms of kVa.
Don't quite understand the phases etc. Is it as simple as voltage x amps / 1000??
Thanks for any help!
100A per phase is 70kva.
For kVA in 3-phase it's either...
3 * phase_voltage * current / 1000
or
sqrt(3) * line_voltage * current / 1000
Both should give identical answers.
However, are you sure you have the loading correct? As 300A 3-phase would normally mean 300A per phase to me, not split between equally between the phases.
You might have a slight different answering you have a bad power factor.
Hi
^ what they said and..
If it is a supply of that sort of size you could ask the network operator (UKPN or whoever depending on were you are)) for the ASC (authorised supply capacity) . You said "loading" so i am assuming you are trying to understand the capacity available not "what the building is using" which can of course be different.
As above if it is a "100A" 3ph the meter will look much like a "domestic: one" only a little larger. An industrial supply will (usually) have a large metal cabinet above the network operators fuses, this can be 600x600mm isn.. with a meter on the door.
Also bear in mind the "size" of the supply is only part of it - the type of load connected also plays a part. i.e office versus factory with motors etc. This is important for a change of use or similar.
This takes me right back to the 1st year of my degree - we had a whole module on three phase power....
Thanks for the comments.
It's for a compound set up for a construction site. The site accommodation manufacturer has said as above 300 amp 3 phase (100/phase).
When talking to Electricity North West they have advised it that up to 60kVa is a lot easier to hook up then above it so just trying to figure out where I stand.
They are probably quoting peak demand.
You can apply some diversity to that, and run a lower rated input.
For instance, a typical house may have a peak demand of 60amps when a shower and other appliances are on, but it is only for a short period, hence the electric company give you a quota of around 20 (or less) amps in their power consumption calcs.
It works as the loads in the street are spread, or of short duration, so they get away (easily) by calculating 20 amps for each house.