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Student & Learning Zone - City & Guilds
Need help for College paperwork
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<blockquote data-quote="SPECIAL LOCATION" data-source="post: 77401" data-attributes="member: 250"><p>for example.. if you had a 25m run of 1.5mm with 1.0mm CPC</p><p></p><p>the table on pg 166 gives you values for;</p><p></p><p>1.5mm conductor, (R1)</p><p></p><p>1.0mm conductor, (R2)</p><p></p><p>or combined 1.5mm &amp; 1.0mm (R1+R2)</p><p></p><p>so:-</p><p></p><p>25m of 1.5mm is (25 x 12.10)/1000 = 0.302ohms (R1)</p><p></p><p>25m of 1.0mm is (25 x 18.10)/1000 = 0.453ohms (R2)</p><p></p><p>25m of 1.5mm is (25 x 30.20)/1000 = 0.755ohms (R1+R2)</p><p></p><p>so whether you are doing readings with a zeroed long-lead</p><p></p><p>or strapped Live-Earth to get R1+R2...</p><p></p><p>you should know roughly the value you will get on your meter based on the amount of cable you have installed and the CSA of the cables you have installed...</p><p></p><p>on our 25m of 1.5mm example If my R1+R2 was 0.84ohm I wouldn't be too woried...</p><p></p><p>but if I got 1.37ohm, I would be double checking my circuit for a bad termination at an accessory somewhere<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink ;)" loading="lazy" data-shortname=";)" /></p><p></p><p>HTHGuiness Drink</p></blockquote><p></p>
[QUOTE="SPECIAL LOCATION, post: 77401, member: 250"] for example.. if you had a 25m run of 1.5mm with 1.0mm CPC the table on pg 166 gives you values for; 1.5mm conductor, (R1) 1.0mm conductor, (R2) or combined 1.5mm & 1.0mm (R1+R2) so:- 25m of 1.5mm is (25 x 12.10)/1000 = 0.302ohms (R1) 25m of 1.0mm is (25 x 18.10)/1000 = 0.453ohms (R2) 25m of 1.5mm is (25 x 30.20)/1000 = 0.755ohms (R1+R2) so whether you are doing readings with a zeroed long-lead or strapped Live-Earth to get R1+R2... you should know roughly the value you will get on your meter based on the amount of cable you have installed and the CSA of the cables you have installed... on our 25m of 1.5mm example If my R1+R2 was 0.84ohm I wouldn't be too woried... but if I got 1.37ohm, I would be double checking my circuit for a bad termination at an accessory somewhere;) HTHGuiness Drink [/QUOTE]
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Need help for College paperwork
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