https://communities.bentley.com/products/building/performance/f/hevacomp-forum/94983/connect---max-zsTable 41.3 of BS 7671 stipulates the maximum Zs for circuits. Having printed off the impedance results for a project a number of circuits are in excess of the maximum permitted zs from table 41.3 How does Connect carry out a calculation, and thenen-USTelligent Community 12https://communities.bentley.com/thread/276505?ContentTypeID=1Fri, 28 Feb 2014 13:30:45 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:a940a1d7-d32a-4792-95ee-f52116fbecaeDuncan Brown<p>Stuart0 - We usually find that where we can incorporate formula&#39;s rather than lookups, then the forumula will give a more accurate representation. This could differ from the table slightly. </p><div style="clear:both;"></div>https://communities.bentley.com/thread/276346?ContentTypeID=1Thu, 27 Feb 2014 12:20:33 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:13c224df-9b38-49c2-a08f-b7a37266cdffStuartO<p>Duncan,</p> <p>Thanks for the response.</p> <p>In summary, as long as the permitted disconnection is achieved a higher Zs than table 41.3 is permissible. &nbsp;</p><div style="clear:both;"></div>https://communities.bentley.com/thread/276339?ContentTypeID=1Thu, 27 Feb 2014 11:02:19 GMT6dad98f5-dbc9-4c4d-a9ba-e9da8dc6aa8e:0eb7d04c-7fdb-43a0-90ee-922f6ef6bdb6Duncan Brown<p>Stuart0 - the software should flag any earth fault disconnection issues in the &quot;end of calculation&quot; report. You should bare in mind, however, that rather than use a table of figures, the software considers the equation in 411.4.5 (this is allowed for by the statement in 411.4.7)</p> <p>If there a specific item in a project that you wish us to examine, then please let us know. </p><div style="clear:both;"></div>