reg 514.10.1 regarding 400 volt label

[333rocky333]

When do you need a 400 volt label ?

regarding nominal voltage, U and Uo

In the late 16th it was different to the on site quide.

In the 17th it is still different to the on site guide but the other way round.

I know its best practise to fit one anyway .

 

[Spark123]

Personal thoughts are there is a glitch in the OSG as if you read the (ii) it starts talking of nominal voltage (Uo) between simultaneously accessable equipment!

 

[GaryMo]

Looking at a model EIC, page 333 BS7671:2008, under nature of supply parameters it has Nominal Voltage, U/Uo.
U is voltage between lines and Uo is nominal voltage to earth.

So, if an enclosure which isn't expected to house 400v then you apply a warning notice informing of the voltage present.
Enclosures containing terminals or other fixed live parts having 400v present, although separated though can be simultaneously reached by a person should have a warning notice informing of the voltage present.

That's how I interpret it from reading BS1761:2008, OSG is in the van so will have a look in there later.

 

[333rocky333]

U/Uo.
U is voltage between lines and Uo is nominal voltage to earth.

same as on the symbols page 36, however that sends you to 411.6.4 page 51/52 where U is now voltage between line conductors
( although that is for It systems, so may be the reason)

In the definitions a Line conductor is not a neutral

So I take it U is phase to phase
and Uo phase to earth
So what is the symbol for phase to neutral, is there one

 

[GaryMo]

I see where you're coming from but I noted the text on the model EIC due to 400v and 230v both being referred to as nominal.

I agree that U is voltage between lines and Uo is voltage between line and earth.

 

[TicklyT]

Juust got me thinking... Any equipment with a UPS should probably be labelled, even if everything is fed from the same phase. If the UPS supply is disconnected, and other supplies remain live, the free running UPS output can drift 180 degrees out of phase with the mains supply. You could then have 460 Volts AC between two adjacent 230Volt sockets