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Electrical Inspection & Testing Forum
Some pics from that hotel PIR
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<blockquote data-quote="Sidewinder" data-source="post: 133134" data-attributes="member: 9512"><p>Lostit,</p><p></p><p>Breaking capacity of a circuit breaker / fuse is just that it is the maximum current flow that it is capable of interrupting.</p><p></p><p>The device does not have to be re-useable after the fault.</p><p></p><p>Difficult obviously with a fuse! <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite7" alt=":p" title="Stick out tongue :p" loading="lazy" data-shortname=":p" /> </p><p></p><p>A "normal" domestic type MCB to 60898 is typically capable of interrupting a fault current of 6kA.</p><p></p><p>Fault current is limited by many things not just resistance, which is why we quote impedance on our certificates even though we actually apply a DC voltage to test, thus we only measure resistance. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite9" alt=":eek:" title="Eek! :eek:" loading="lazy" data-shortname=":eek:" /> </p><p></p><p>Think of the typical local distribution loop, you have your local HV/LV transformer, normally a Delta/Star device.</p><p></p><p>That is the HV primary is a delta wound transformer.</p><p></p><p>The coupled secondary is a star wound device.</p><p></p><p>The HV side will have its own earthing and protection systems, these may be local, or remote depending on the DNO design. Now at this point I</p></blockquote><p></p>
[QUOTE="Sidewinder, post: 133134, member: 9512"] Lostit, Breaking capacity of a circuit breaker / fuse is just that it is the maximum current flow that it is capable of interrupting. The device does not have to be re-useable after the fault. Difficult obviously with a fuse! :P A "normal" domestic type MCB to 60898 is typically capable of interrupting a fault current of 6kA. Fault current is limited by many things not just resistance, which is why we quote impedance on our certificates even though we actually apply a DC voltage to test, thus we only measure resistance. :o Think of the typical local distribution loop, you have your local HV/LV transformer, normally a Delta/Star device. That is the HV primary is a delta wound transformer. The coupled secondary is a star wound device. The HV side will have its own earthing and protection systems, these may be local, or remote depending on the DNO design. Now at this point I [/QUOTE]
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Some pics from that hotel PIR
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