Specifications

Phase Conductors Sizing
The default setting of ‘Auto-size for current-carrying capacity and voltage
drop limits’ means that when a calculation is carried out, cables with their
Size set to Auto and busbars with their Rating set to Auto, will be first
automatically sized for their current-carrying capacity and then, where
necessary, increased in size to meet the voltage drop set limits.
Alternatively, setting ‘Auto-size for current-carrying capacity only’ means
that conductors will not be re-sized to deal with circuits where the voltage
drop exceeds the set limit.
Voltage Drop Limits
The default setting applies the limits defined in BS 7671:2008 Appendix
12. The values of the limits for lighting and non-lighting loads will depend
on the Supply Type defined in the Voltage tab of the Source dialog. The
voltage drop allowance for wiring systems over 100 m in length
described in Appendix 12 can be included or not, as required.
Alternatively, the voltage drop limit to any final circuit can be set to a
specified value. The value can be expressed as a voltage drop limit in
percentage or absolute terms, or as a minimum voltage at the load
terminals.
AMTECH Quick Guide 2008 -17
th
Edition • 15