Can anyone confirm the configuration of the 400/230V distribution scheme in Nigeria i.e. TNS or TN-C-S. We have a Client who wanted to use a 3w distribution but have found that 4w is required.
It is not my speciality but NERC is the relevevant standards body.
Looking quickly at the
goto chapter 7 which is essentially the cut down regs
It seems that the standard configurations are
7.1General Provisions
This Regulation applies to all user‟s sites installations connected to any electrical power supply under the authority of a license granted under the Act (whether granted before or after the coming into force of this Regulation), and to all user‟s sites irrespective of their source of supply shall be in the following configurations and voltages:
a. Single phase 2 wire supply at 230 Volts
b. Three Phase 4-wire supply at 400 Volts
c. Single Wire Earth Return (SWER) supply at 230 Volts
I read that as most likely TT or SWER are your options.
I do not see any reference to tn earthing as we would recognise it in Europe. You could do worse than contact NERC for clarification.
M.
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