TP&N equipment rating

[chr106]

TP&N voltage ratings for products, equipments etc are expressed alternatively as 440/250VAC or 250/440VAC (or 250/440 Vac etc), or in other representations. What is the "technically correct" format and in what standard/specification is it embedded? (is it IEC60050?).
Thank you.

 

[Avo Mk8]

I believe you are right, the International Electrotechnical Vocabulary IEC60050- part something should cover it, but good luck finding the section that covers it among the hundreds of parts. I would be surprised if it defined in detail the distinction you are making. It seems traditional to put the higher voltage first - eg 440/250VAC (though there are plenty of examples the other way round), and I don't think your last example with lower case is preferred to upper case.
if you are asking in relation to labelling a product, or preparing the documentation or user manual, it would be worth talking to the Notified Body doing approval for you, (if that's happening)

 

[Lucien Nunes]

Cable specifications are usually of the form Uo/U or Uo/U (Um) and I see various references to that format being defined in BS7870 Part 4.10 2011. Where that gets it from is a good question but might be a starting point.

 

[chr106]

I believe you are right, the International Electrotechnical Vocabulary IEC60050- part something should cover it, but good luck finding the section that covers it among the hundreds of parts. I would be surprised if it defined in detail the distinction you are making. It seems traditional to put the higher voltage first - eg 440/250VAC (though there are plenty of examples the other way round), and I don't think your last example with lower case is preferred to upper case.
if you are asking in relation to labelling a product, or preparing the documentation or user manual, it would be worth talking to the Notified Body doing approval for you, (if that's happening)

Thank you for your reply.

 

[chr106]

Cable specifications are usually of the form Uo/U or Uo/U (Um) and I see various references to that format being defined in BS7870 Part 4.10 2011. Where that gets it from is a good question but might be a starting point.

Lucien, thank you for this advice. Chr106