Specifications

AMTECH Quick Guide 2008 -17
th
Edition • 11
Maximum Zs values
The formula for calculating maximum Zs is stated in Appendix 3 of BS
7671. Previous versions of the standard require that the open circuit
voltage (Uoc) be divided by the current causing automatic disconnection
of the protective device (Ia) to determine Max Zs. However, in BS
7671:2008 the open circuit voltage has been replaced with the nominal
a.c. rms line voltage to earth (Uo).
This change will result in calculated maximum Zs values which are about
4% lower than those calculated under the 16
th
Edition Wiring
Regulations.
FastTest v9 includes the updated maximum Zs values stated in BS
7671:2008 Tables 41.2 to 41.4.
Installation methods
Appendix 4 of BS 7671:2008 has been significantly revised. The
terminology used to describe References Methods has been changed. In
addition some new methods have been added.
FastTest v9 has been updated to include the changes to BS 7671:2008
Appendix 4.
NICEIC certificates
The NICEIC have updated their computer friendly certificate stationery in
response to the publication of BS 7671:2008. NICEIC members can
purchase the updated certificate stationery directly from the NICEIC.
FastTest v9 is designed to work with the following NICEIC certificate
types:
• IMR2 - Minor Works (Red)
• ICR2 - Electrical Installation (Red)
• IPR2 - Periodic Inspection Report (Red)
• DCR5 - Domestic Electrical Installation (Red)
• FHR4 - Fire Alarm for Dwelling (Red)
• DMQ3 - Minor Works (Purple)
• DCQ4 - Domestic Electrical Installation (Purple)
FastTest v9 will not print onto 16
th
Edition certificates.