# 380 V system

Solar Expert Posts: 45
Hello everybody,

I went to a workshop to design a grid-tied solar system, I noticed very strange thing which is that some appliances are working as 3-phase 380 V (like big motors) and other appliances are working as normal 230 V. can you explain how I can operate both 380 V and 230 V appliances on same system (line/meter).
I thought we must have a specific connection for 380 V appliances and another specific connection for 230 V.

Thanks

Mina

Re: 380 V system

It appears that you have 230/380 VAC 3 phase Wye power (or also called "Y" or "Star")...

http://en.wikipedia.org/wiki/Three-phase_electric_power

You should have 3 "hot legs" (~380 volts from L1 to L2, L1 to L3, L2 to L3) and ~230 volts from any Lx leg to Neutral. In the US, the center of the Wye (Y/Star) is grounded (ground bonded neutral wire). So, nomrally you would have either a 3 wire 3 phase 380 VAC (3 hots) and 4 wire 3 phase (3 hots and a neutral).

Technically, I would expect 380 VAC / square root (3) = 219 VAC
Or 230 VAC * sqrt (3) = 390 VAC

Sometimes power system will split the difference (what is typically called 230/380 VAC is not exactly 230/380 VAC). In the US we have both 120/240 VAC and 120/208 VAC power available (difference between Delta and Wye powered three phase systems).

For three phase power, there is usually a sqrt (3) (~1.7205) conversion factor between various conversions (line to neutral, single phase current measurement to total power, etc.).

I don't know anything about general power usage in Egypt--So I will be of limited help here. I am just fitting what you have told us so far with what (little) I understand of 3 phase power.

So, your three phase appliances would be connected (usually) to the three hot wires (~380 volts) and the single phase appliances would be connected to the Neutral (center tap of the transfomrer set) to one of the Hot connections for ~230 VAC. In a large factory/office building, the loads are distributed between L1/N, L2/N, and L3/N to have "balanced" loads on all three phases.

Note there can be other standards and "typical" voltages. Sometimes people may say 230 VAC, but you may measure closer to 219 VAC. And both voltages can be "close enough" for many devices.

In the US we typically have available (office/factory) 120, 208, 240, 277, 480 VAC available in some combination (mix of Wye, Delta and High/Low voltage services). It depends on what the customer needs and what the local utility offers. In different regions of the US, what is "standard" from one utility may be different from what is offered by other utilities.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Banned Posts: 17,615 ✭✭✭
Re: 380 V system

Bill;

The reason for the Voltage discrepancy is the "new European 230 Volt standard" where they accommodated all the wide-range of Voltages available by increasing the "acceptable" tolerance. So their "230 Volts" runs anywhere from 210 to 250. Nice, eh? This would be carried over to other countries using the "standard" so Egypt probably has single phase 230 VAC 50 Hz and 380 VAC 3-phase with a 219 VAC L to N tap (which would be within the power range).

On the whole our North American system doesn't look bad compared to other countries. The range of outlets overseas is a nightmare!
• Solar Expert Posts: 295 ✭✭✭
Re: 380 V system
Bill;

The reason for the Voltage discrepancy is the "new European 230 Volt standard" where they accommodated all the wide-range of Voltages available by increasing the "acceptable" tolerance. So their "230 Volts" runs anywhere from 210 to 250. Nice, eh? This would be carried over to other countries using the "standard" so Egypt probably has single phase 230 VAC 50 Hz and 380 VAC 3-phase with a 219 VAC L to N tap (which would be within the power range).

On the whole our North American system doesn't look bad compared to other countries. The range of outlets overseas is a nightmare!

New? A nightmare? Not at all, it is the norm since the day I was born. North America, on the other hand, is the nightmare.

+-239 Countries of which +-49 are below 220v, 50hz. :-)
Majority is 220v - 240v @ 50hz.
http://en.wikipedia.org/wiki/Mains_electricity_by_country

and you drive on the wrong side of the road and the have inches and foot measurement standards ... Sorry, I could not help hijacking this thread. ROTFLMAO :-)
5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.

• Banned Posts: 17,615 ✭✭✭
Re: 380 V system

Yeah the 50 Hz frequency is why you can never get anything done on time in a foreign country.

Gotta love the ... HOW many different types of plugs?
• Solar Expert Posts: 295 ✭✭✭
Re: 380 V system
Yeah the 50 Hz frequency is why you can never get anything done on time in a foreign country.

You have NO idea the complexities 50 Hz frequency can create.
Gotta love the ... HOW many different types of plugs?

We just cut them off, push the wires in and walla, plug problem solved. :-) (ROTFLMAO)
5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.