Voltage Drop<\/p>\n
Think of voltage drop as similar to a loss in pressure along a water pipe over a long distance. So just like with water in a pipe a conductor will lose ‘x’ amount of pressure measured in millivolts ‘mV’ for every Amp ‘design current’ that flows along it for each meter.<\/p>\n
This is much easier to calculate than it looks…<\/p>\n
The formula for Voltage Drop is (mV\/A\/m) X Ib X Length \/ 1000<\/p>\n
How many millivolts per amp per meter (mV\/A\/m) a conductor loses can be found in the current carrying capacity and voltage drop tables in Appendix 4 of BS7671.<\/p>\n
Note the mV\/A\/m figures are at the far right of the tables but some of the tables expand over 2 pages so look on the second page. The design current is the current expected to be used by the circuit (Watts \/ Voltage). If this is not know then it is acceptable to use the rating of the protective device (In) as Ib will never be larger than this amount. Length is in meters. Then finally we divide it by 1000 to convert it from mV into V.<\/p>\n
Maximum permitted levels of Voltage drop can be found in BS7671 Table 4Ab (i) 3% for lighting (6.9V) or 5% for other uses (11.5V).<\/p>\n","protected":false},"excerpt":{"rendered":"
Voltage Drop Think of voltage drop as similar to a loss in pressure along a water pipe over a long distance. So just like with water in a pipe a conductor will lose ‘x’ amount of pressure measured in millivolts ‘mV’ for every Amp ‘design current’ that flows along it for each meter. This is…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[1],"tags":[],"class_list":["post-272","post","type-post","status-publish","format-standard","hentry","category-general","th-blog blog-single has-post-thumbnail"],"yoast_head":"\n