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What are the differences between 380v AC, 400v AC and 415v AC Mains Supplies and what voltage equipment should I use?
For many years, mainland Western Europe has used a mains, 3 phase, electricity supply nominally rated at 380v AC 50Hz while the UK used 415v AC 50Hz.
Currently, all Western European 3 phase supplies are classified 400v AC. In reality there is no 400v AC supply unless you create one locally. 400v AC was a “standard” created during European "harmonisation" to give a single voltage standard across Western Europe, including UK and Irish Republic.
Although the ideal would have been to have a single voltage there were too many political, financial and technical obstacles to reduce UK voltage to European levels or to increase European voltage to UK levels, so a new standard was created to cover both. This was achieved by changing the tolerances of previously existing supply standards. UK voltage to 415v AC +6% and -10% and European to 380v AC +10% and -6% (thereby creating a manageable overlap) and we would call these two combined 400v AC, despite the fact that nobody was intentionally generating at 400v AC!
Depending on the voltage sensitivity of the product and the variance from nominal of the actual supplied voltage, it may not be advisable to use a 380v AC specific device in the UK or a 415v AC specific device in Mainland Europe etc. For instance a 415v AC supply can rise to as high as 439.9v AC and still be within tolerance, but the maximum assured rated voltage for a 380VAC product is only 418v AC. A 380v AC supply can drop as low as 357.2v AC within tolerance but the minimum assured voltage for correct performance of a 415v AC product is 373.5v AC. It may work perfectly well either way but it could be, technically, outside the specification of the equipment with obvious implications. A 400v AC product must be compatible with all voltages across this range.
If a product is to be used in the UK a 415v AC rated device is ideal but either 415v AC or 400v AC products can be used with confidence.
If a product is to be used in mainland Europe or Irish Republic a 380v AC rated device is ideal, but either 380v AC or 400v AC products can be used with confidence.
Currently, all Western European 3 phase supplies are classified 400v AC. In reality there is no 400v AC supply unless you create one locally. 400v AC was a “standard” created during European "harmonisation" to give a single voltage standard across Western Europe, including UK and Irish Republic.
Although the ideal would have been to have a single voltage there were too many political, financial and technical obstacles to reduce UK voltage to European levels or to increase European voltage to UK levels, so a new standard was created to cover both. This was achieved by changing the tolerances of previously existing supply standards. UK voltage to 415v AC +6% and -10% and European to 380v AC +10% and -6% (thereby creating a manageable overlap) and we would call these two combined 400v AC, despite the fact that nobody was intentionally generating at 400v AC!
Depending on the voltage sensitivity of the product and the variance from nominal of the actual supplied voltage, it may not be advisable to use a 380v AC specific device in the UK or a 415v AC specific device in Mainland Europe etc. For instance a 415v AC supply can rise to as high as 439.9v AC and still be within tolerance, but the maximum assured rated voltage for a 380VAC product is only 418v AC. A 380v AC supply can drop as low as 357.2v AC within tolerance but the minimum assured voltage for correct performance of a 415v AC product is 373.5v AC. It may work perfectly well either way but it could be, technically, outside the specification of the equipment with obvious implications. A 400v AC product must be compatible with all voltages across this range.
If a product is to be used in the UK a 415v AC rated device is ideal but either 415v AC or 400v AC products can be used with confidence.
If a product is to be used in mainland Europe or Irish Republic a 380v AC rated device is ideal, but either 380v AC or 400v AC products can be used with confidence.
Released for:Schneider Electric UK
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