ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
AreMetal Ladders Ever OK For Electrical Work?
by HotLine1. 01/22/18 07:31 PM
Photocell
by twh. 01/22/18 05:06 PM
VDE 0100 to introduce AFCIs
by sparky. 01/20/18 05:09 PM
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 16 guests, and 6 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
breaker trip #86587
11/13/03 08:29 AM
11/13/03 08:29 AM
R
Reel-Break  Offline OP
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
Re: breaker trip #86588
11/13/03 08:58 AM
11/13/03 08:58 AM
R
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.

Re: breaker trip #86589
11/13/03 11:01 AM
11/13/03 11:01 AM
B
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


Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
cookcc
cookcc
California ,Long Beach
Posts: 28
Joined: May 2007
Show All Member Profiles 
Top Posters(30 Days)
Admin 21
sparky 15
Potseal 15
Popular Topics(Views)
243,599 Are you busy
180,406 Re: Forum
170,869 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.013s Queries: 14 (0.004s) Memory: 0.9496 MB (Peak: 1.0752 MB) Zlib enabled. Server Time: 2018-01-23 14:04:30 UTC