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Topic Title: EICR Question
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Created On: 21 April 2014 09:10 PM
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 21 April 2014 09:10 PM
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Chris1933

Posts: 7
Joined: 30 September 2013

I've just completed an EICR on an industrial installation and I've a couple of observations that I am not sure how to code (if at all).

1) 63A fuses in 60A carriers - C3?
2) Old style fuse disconnectors that can be opened by pulling the lid, exposed parts inside (was thinking 416.2.4 non compliance) - C2?
3) PSC measured at source is 10KA, 6KA MCB "downstream" and 7.4KA measured at MCB.

Any thoughts?

Regards

Chris
 21 April 2014 11:38 PM
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AJJewsbury

Posts: 11493
Joined: 13 August 2003

1) 63A fuses in 60A carriers - C3?

Grumble. That's the "standards" people making incompatible changes again - like when we started using 6A MCBs but still had 5A light switches. Mathematically wrong, but we're left with little option in practice. I'd suspect that there isn't a problem in reality - there's surely a bit of manufacturing tolerance in the old 60A carrier. If you really want to to be sure, what's the fuse protecting? Is it liable to small overloads of long duration? If not then I'd say nothing to worry about.
2) Old style fuse disconnectors that can be opened by pulling the lid, exposed parts inside (was thinking 416.2.4 non compliance) - C2?

It can definitely be opened without a tool and without switching off? Where is it located? Is it perhaps in a switch room with restricted access? (i.e. the room can only be opened using a key or tool...)
3) PSC measured at source is 10KA, 6KA MCB "downstream" and 7.4KA measured at MCB.

What's the upstream protective device? Usually a HBC fuse (or MCCB) will 'backup' MCBs adequately (like with domestic CUs being rated at 16kA even if they come with 6kA breakers) - but you might need manufacturer's data to prove it.

- Andy.
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