My company is venturing into 3-phase power distribution for the IT/Telecom industries in Europe and I need to know the 'standard' 3-phase voltages and connectors used.

We're designing both Delta(3pins plus ground) and Wye(4 pins plus ground) and are trying to verify the most common voltages and input connectors used.

Currently the thought is for the Delta to design for 250V with use of the IEC 309 blue connectors with the ground at position 9 and for the Wye, 277-400V with IEC 309 red connectors with the ground at position 6.

Are these choices correct for a majority of industrial IT/Telecom datacenter infrastructures (power grid)?

Yes, the plug patterns you mention are correct for the systems used in Europe. I would like to point out that the 230/400V 3-ph system is far more common than the 230V 3-ph. In fact, most countries exclusively use 230/400V, but in a few countries it's probably a good idea to offer the 230V 3-ph as an option.

The IEC 309 connectors are the norm throughout Europe and no other type of connector need to be considered for 3-ph.

For small power demands there are also single phase plugs, both IEC 309 (16-63A) and the general purpose national types (10-16A).

Here is a different angle.

If in the IT/Telecom datacenter, all the end equipment is running off 230V 50/60 Hz single-phase, would it be reasonable to assume that the center likely has a Transformer to bring the grid 3 phase 400V down to 230V for distibution within the facility?

This would then point my company to use the 208-250V rated IEC 309 blue connectors would it not?

It would be a very unusual setup. Normally, end equipment is connected between phase and neutral (230V). Transformers to convert from 400V to 230V or 115V without neutral are sometimes used in special locations where extra safety is desired, such as laboratories, construction sites and oil platforms.

[This message has been edited by C-H (edited 01-23-2004).]

An additional note: The voltage supplied at ordinary outlets is 230V throughout the entire European Union, with an permitted variation of +/-10%. For various reasons, such as voltage drop in the customers wiring (max 4%), unexpected load fluctuations and poor engineering, the voltage can on occasion venture outside this band and it is therefore adviseable to allow a somewhat wider margin when designing equipment. The frequency is a stable 50 Hz througout the continent.

Also it's worth noting the actual supply voltages... The European area (i.e. all CENELEC countries) have standardised on nominal 230/400V system at 50 Hz

Originally:

UK, Malta, Cyprus: 240/415V 50Hz
ALL other countries 220/380V 50Hz

Appliences are now rated 230V Single phase or 400V 3-phase and work happily on either system. Actual supply voltages will gradually change to 230/400V.

Any equipment should be rated 230/400V 50hz and should have no problem dealing with either of the above supply voltages.

IT and Telecommunications equipment tends to be connected at 230V 50Hz i.e. between phase at 230V and ground referenced neutral at 0V.

I'm not sure about elsewhere but in Ireland where 3-phase power is used to provide 230V circuits each 230V circut must be protected by its own RCD and over current protection. Using 3-way 3-phase RCDs/Breakers that cover the whole system would not be an acceptable sollution on their own.

In general it would be rather unusual to plug an IT installation into a 3-phase socket. Typically you'd expect hardwired 230V 16A circuits all fed from a board of circuit breakers protected by RCDs etc.

In most countries 3-phase would only be used for loads that draw ?32A at 230V and in the UK & Ireland almost exclusively for industrial situations e.g. large motors.

UPS and various conditioning systems would also be quite normal in IT and Telecom systems

Most IT equipment is connected with normal domestic single phase plugs, usually CEE 7/7 except in the UK, Ireland, Cyprus, Malta (BS1363), Italy, Denmark and Switzerland.

Other common power connections in IT:
Hardwired

IEC 320 connectors are quite extensively used in IT, Telecoms and Studio setups too.

Hmm, 230V 3phase?.
I would assume that this would be a Wye system, not Delta.
As there would have to be a Neutral to effect the 230V supply, otherwise there would be a 400V Delta supply, Delta supply has no Neutral.
Delta is really only used in Distribution systems and for Delta-wound Motors.
djk, you say that Ireland will become 230/400V eventually, is this a European thing?, how about the UK?.
Will all of the HV voltages be standardised as well? (ie: 11, 22, 33 and 66kV).
Just wondering.

As far as I know here new MV/LV xformers output 230V/400V not the "traditional" 220V/380V.

Much of the rural MV distribution network is being upgraded from 10kV to 20kV to increase capacity so as that happens lots of MV/LV xformers are being replaced.

I can't see direct supplies at MV or HV being standardised though as most of the customers of these supplies aren't exactly using off the shelf equipment anyway and in most cases they're transforming to other voltages before use anyway.

MV here being 10, 20 and 38kV with the odd connection to industrial users at 110kV (HV)

Those voltages seem quite common elsewhere too.

Most data/IT equipment in Europe is designed to run on a 230V single-phase supply, and a 230/400V (or thereabouts!) 4-wire 3-phase wye system is standard.

There are still a few areas where 220V is obtained as two phases of an old 127/220V wye system, so the equipment should allow for the fact that one side of the supply might not be grounded. Equipment built to European specifications needs to allow for reversed polarity on the supply anyway, due to the widespread use of Schuko (reversible) plugs.

Paul:

I've seen some IT equipment that had notes in the installation instructions pointing out that 127+127 systems should not be used.

Any idea why?

Oh my, I think I should not have brought up the voltages since I seem to have made this thread rather confusing. Sorry, Loquetis!

A comment on Djk's comment:

In Sweden it is the standard solution.


This differs somewhat from country to country. The blue 32A single phase connectors are rare in Sweden while the red 3-ph 16A are common. This only serves to illustrate the diversity of the European system. In Scandinavia you can buy a 16A 3-ph extension cord in any D-I-Y store while on the British Isles, you'll find the 32A single phase cords instead. Poor manufacturers!

A comment on Paul's comment on the 127/220V system: Despite the fact that it may be grounded at the center point, the plugs and outlets are the same as in a delta configuration as only the phases are supplied to the equipment.

I can't think of a compelling reason why 220V equipment designed to European specifications shouldn't be used across two phases of 127V.

Standards require equal protection, insulation etc. on the neutral and line conductors throughout, and due to the possibility of reversed polarity on typical European plugs, the neutral line cannot be relied upon as a 0V reference point in any way.

I've operated my PC set for 220V across 125V-0V-125V here in the USA, and it works fine. Also the monitor. The PC uses the usual switching power supply that has a 115/230 switch on the back. Power switches in PCs switch both sides of the line, and the wires are usually brown and blue. So in this case both lines are hot. Not a problem as the equipment has to be designed to expect either line to be hot.

Doing this trick is handy if you have a room full of servers. You can avoid overloaded neutrals due to harmonic currents from switching power supplies in a 208 Y system. Most of these supplies don't mind 208V. They are designed to operate off of japanese 100V powerlines, and with that rear voltage switch switched to "230V", it's like 200V. That switch changes the supply from a voltage doubler rectifier circuit to a bridge rectifier circuit.