ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
Potseal 11
Recent Posts
600 KW 120/208 3 Phase Y protection
by SteveFehr. 07/23/17 09:46 AM
1913 American Electrician's Handbook
by gfretwell. 07/20/17 01:08 PM
Green House wiring
by ghost307. 07/20/17 09:10 AM
Permit Snafus...AHJs and Contractors Jump in
by HotLine1. 07/18/17 08:06 PM
New in the Gallery:
SE cable question
Popular Topics(Views)
239,280 Are you busy
174,739 Re: Forum
167,113 Need opinion
Who's Online Now
0 registered members (), 66 guests, and 7 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#86587 - 11/13/03 09:29 AM breaker trip  
Reel-Break  Offline
Member
Joined: Apr 2002
Posts: 178
nc
Can some explain the current fault conditions.I was explaining to a guy about inrush current on breaker being more than breaker set point for a short time period before it trips.I really don`t feel I`ve done a good job explaining it so I`m asking for some assistance.How does a breaker lets say 40 amp double pole square D home line work to protect agaist fault current.


2017 / 2014 NEC & Related Books and Study Guides

#86588 - 11/13/03 09:58 AM Re: breaker trip  
Redsy  Offline
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Most convebtional CB's have a thermal component which responds, (relatively slowly)
to lower level overloads in a manner which is inversely proportional (time v. current)to the overload.
There is also a magnetic component, which in the event of a ground-fault or short-circuit, will respond almost instantaneously to this, normally much higher level of overcurrent.


#86589 - 11/13/03 12:01 PM Re: breaker trip  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
Another term for how breakers and fuses react to overcurrent is an inverse time-current characteristic. Simply—the higher the current, the faster the device operates.

Detail: www.usace.army.mil/publications/armytm/tm5-811-14/

Quickie: www.cbibreakers.com/magnetic.asp?menu=sixth



Member Spotlight
waymag
waymag
dallas, texas, USA
Posts: 67
Joined: January 2002
Show All Member Profiles 
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.015s Queries: 14 (0.005s) Memory: 0.7515 MB (Peak: 0.8759 MB) Zlib enabled. Server Time: 2017-07-24 14:39:01 UTC