http://www.voltimum.co.uk/sites/www.voltimum.co.uk/files/bs7671-amd-3-dcp_0.pdf
Some interesting changes, some are bloody pointless though IMHO.
Some interesting changes, some are bloody pointless though IMHO.
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Discuss Amendment 3 DPC in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net
Cmin is the minimum voltage factor to take account of voltage variations depending on time and place, changing
of transformer taps and other considerations.
NOTE 1: For a low voltage supply given in accordance with the Electricity Safety, Quality and Continuity Regulations
2002 as amended, Cmin is given the value 0.95.
This is to take account of the lower end of the range of the tolerances and VD of a nominal 230V/400 supply, if you notice they have also re-calculated the max Zs values (OCPD tables etc.) to take this into account too.
What gets me with this is that they already lowered these once to "harmonise" the 230/400 calcs (from 240/415), this new lowering probably makes some sense if you have a "real" 230/400 supply which we don't (we only changed the tolerance band) unless we are really lowering our supply voltage this time ?
More significantly, the commercial/industrial supervised person "get out clause" for RCDs has all but been removed, unless you are prepared to sign a RA to say otherwise, I cannot see many people wanting to sign that.
This will cause some problems with offices and the like.
Also, have a look at the altered tabulated max Zs values for B, C and D curve 60898s!
What a ball ache, that means the big YELLOW book is gonna have to come out every time I fill in a cert now!
All the Z esses for all (it seems) devices are 5% lower.
All the Z esses for all (it seems) devices are 5% lower.
Reply to Amendment 3 DPC in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net