3 phase minimum voltage

[madscot]

Morning all

I know the minimum permissible single phase voltage is 207v. What is it for 3 phase? Is the minimum voltage calculated on 380v,400v,415v? My phone crashed so I lost my 10142 I had on it.

Thanks

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[Dylboy]

The equipment shall be suitable for operation on the maximum steady (r.m.s.)
voltage and overvoltage to which it is likely to be subjected. Equipment shall
be rated in accordance with the intended application for use on one of the
following voltages used in South Africa:
a) A.C. circuits:
1) standard voltages of
i) 230 V single-phase,
ii) 230/400 V three-phase four-wire, and
a tolerance of ± 10 % on these voltages.
NOTE For certain equipment it may be necessary to consider the lowest voltage
that is likely to occur.
2) declared voltages of 525 V three-phase three-wire is a commonly used
voltage and the tolerance is ± 5 %.
NOTE Declared voltage is the voltage declared by the manufacturer up to the
maximum of 1 000 V.
[emoji2398] SAB

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[Isetech]

As Dylboy mentioned 10 %, however you have to take the voltage on site into consideration.

The sit eI am working on at the moment

Red = 221
White = 225
Blue = 228

While carrying out tests today the voltage fluctuated more than 10 volts from one DB to the next.

I have a site where I connected a PQA, the grid voltage ranges from 260 VAC down to 165 VAC, reported to the supplier, they sent a sparkie with a duspol tester to fix the issue. We have had to install online UPS units to stablise the power to prevent damage to the servers.