Just in from Square D [RE-wrenches]

[hugh piggott]

<x-flowed>There are all sorts of faults which could develop.

At 10:12 am -0800 10/3/01, Drake Chamberlin - Electrical Energy wrote:
>
>The code requires overcurrent protection in ungrounded conductors.

As I understand it, this is because there could be a fault earth 
circuit back to the other pole behind the breaker (and this would not 
already have blown a fuse/tripped a breaker, because the system is 
floating).
>
>The resistance varies with the length of the run.  It doesn't take a 
>very long run of #12 wire to limit the surge of low voltage current 
>to well within the bounds of the 5000 DC amp interrupt capability of 
>the QO breaker.

Hmm but who is to say where the fault is going to happen - which end 
of the wire?  Or right at the breaker?
>
>ARTICLE 720 -- Circuits and Equipment Operating at Less than 50 Volts
>
>720-4. Conductors
>Conductors shall not be smaller than No. 12 copper or equivalent.

that's a bit fascist.  What about circuits with 1 amp fuses?
-- 
Hugh

Scoraig, Scotland
http://www.scoraigwind.co.uk

- - - - - - -
To send a message:
 RE-wrenches at topica.com

The archive of previous messages: 
 http://www.topica.com/lists/RE-wrenches/

List rules & etiquette:
 http://www.mrsharkey.com/wrenches/etiquete.htm

To unsubscribe send a message to: 
 RE-wrenches-unsubscribe at topica.com

To check out the other RE-Wrench participants:
 www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine: 
 www.homepower.com

For info contact list moderator by email:
 michael.welch at homepower.com

____________________________________________________________
T O P I C A  -- Learn More. Surf Less. 
Newsletters, Tips and Discussions on Topics You Choose.
http://www.topica.com/partner/tag01

</x-flowed>