Dave Plowman (News) wrote:

In article ,
Bob Eager wrote:

It's the 'jargon' used by 16th Edition...!
Presumably to differentiate from three phase?

No, 3-ph 400 V is still low voltage. LV is anything up to 1000 volts AC
or 1.5 kV DC between conductors, or 600 V AC & 900 V DC to earth.

Still rubbish though. ;-)

Not really, these voltage classes have been in use for decades. 11 kV
(line) only counts as medium voltage.

It's context dependent. A 1.5 kV rail inside a piece of electronic
equipment would probably be labelled 'EHT'. For electricity generation,
distribution and supply it's only LV.

For line voltage (i.e. voltage between phases) in 3-ph distribution systems:

- LV is up to 1 kV
- MV is 1 kV to 36 kV
- HV is 36 kV to 245 kV
- EHV is 245 kV

In BS 7671:

- ELV is up to 50 V AC or 120 V ripple-free DC, whether between
conductors, or to earth

- ELV sources are either SELV (floating wrt ground) or PELV (earthed)

- LV is anything exceeding ELV up to the limits defined above.

--
Andy