Discuss 3 phase supply size in the Electrical Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

J

James sparks

Hi all,

I need to put in a 3 phase supply for a piece of equipment in a commercial unit. They've sent the spec sheet for the item over and all it says is

Current type (Ph/V/Hz): 3/420/50
Power rating (kW): 7.8


I just want to clarify if it's 7.8kW per phase or 7.8kW total over all 3 phases.

Thanks!!
 
usually if you use a kw rating in the same spec as 3ph its per phase ...
 
[h=3]Technical data[/h]
Current type Ph/V/Hz
3/420/50
Flow rate (l/h)
500-1000
Pressure (bar/MPa)
30-200/3-20
Max. temperature (°C)
155-80
Power rating (kW)
7.8
Consumption fuel oil (kg/h)
6.4
Fuel tank (l)
25
Fuel tank (cc³)
-
Weight (kg)
171
Dimensions (L x W x H) (mm)
1330x750x1060
Detergent tank (l)
20
 
its per phase 7.8kw per phase otherwise it would have stated single
 
If you have a spec asking fot 3ph and a Kw rating its Kw per phase .. . no disrespect to other posters but your guessing and not experienced in 3ph so express this in your post or you may mislead the OP ... I assume a 3ph device is part of the setup like a motor; motors are specd per phase not devided by 3..
 
If you have a spec asking fot 3ph and a Kw rating its Kw per phase .. . no disrespect to other posters but your guessing and not experienced in 3ph so express this in your post or you may mislead the OP ... I assume a 3ph device is part of the setup like a motor; motors are specd per phase not devided by 3..
You are wrong and most of my work is industrial 3 phase.
 
You are wrong and most of my work is industrial 3 phase.

If you request a supply from DNO in Kw then its per phase.
If you get a motor and it says 4kw 400v then its per phase.
If you have a machine that asks for a 3ph supply 10kw then thats per phase.


25yrs of industrial intalls design and machine panel building plus several requests to DNO for supplies or upgrades im sure im not wrong....

Only exception is the occasional machine usually from china and 2nd hand that does go over 3ph and checking the wiring plan or load characteristics can usually identify this but other than that ill say your wrong.

Its always good to cross check these values Ive seen architects mess up if a reading is in KVA on a machine or supply then its likely to be a total demand across the phases as dave points out below but the OP spec'd a Kw value.
 
Last edited:
Consider a 32A three phase mcb, that's 32A per phase. Same goes for KW rating.

Only fly in the ointment I can think of is from UKPN's paperwork where a 100A 3ph supply is described as being a 69KVA 3ph supply.
 
Consider a 32A three phase mcb, that's 32A per phase. Same goes for KW rating.

Only fly in the ointment I can think of is from UKPN's paperwork where a 100A 3ph supply is described as being a 69KVA 3ph supply.


Good point Ive come across before very confusing TBH when the rest of the industry works the other way.
 
I would have said KW per phase myself,hazarding a guess I'd say it's some kind of pressure washer and you can get some very large ones with a fair old inrush on the motor.
 
Are you intending to use a DOL starter? If not then what?
 
It well could have, but then it should have a label on stating what it requires. Us leccies know everything except when it comes to the opposite sex..
 

Reply to 3 phase supply size in the Electrical Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock