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Old April 16th 08, 12:51 AM posted to uk.railway,uk.rec.subterranea,uk.transport.london
David Hansen David Hansen is offline
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First recorded activity at LondonBanter: Jul 2003
Posts: 376
Default Crossing London tube tracks

On Tue, 15 Apr 2008 18:18:08 +0100 someone who may be "Jeff"
wrote this:-

The physical size of the fuse IS important when you are considering
spark-gaps etc, which is what caused the dramatic failure in this case.


Incorrect. What is important in this respect is the breaking
capacity of the fuse. Different designs of fuse, with the same
physical dimensions, are able to reliably break different currents.



Not incorrect, some fuses have fillers in the tube to help prevent arcing at
EHT voltages.


Incorrect. The "fillers" (and indeed the nature of the fuse element)
are one of the determinants of the breaking capacity.

EHT is not a term which is defined in the usual sources. Perhaps you
could tell us what your definition is?

Fuses will normally have a voltage rating as well as a current
rating and type (fast blow, anti surge etc.)


The voltage was stated in the CPC information I was eventually able
to quote. Readers may have noted that none of the information was
for DC.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54