ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Lock-down Thread
by Bill Addiss - 02/27/21 01:16 PM
Northern Tool Recalls Powerhorse Generators
by Admin - 02/25/21 09:49 PM
You will never guess
by gfretwell - 02/25/21 07:48 PM
New tool
by SMOKEYBOB - 02/15/21 04:59 PM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 15 guests, and 19 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
another fire hazard panel #196845 10/29/10 04:19 PM
Joined: Aug 2006
Posts: 356
Niko Offline OP
Member
My client had a short on a GE 15A OCPD and it didn't trip. Today I tested that circuit breaker with a 30Amp load and it wouldn't trip.
Is GE another fire hazard panel? Have any of you had the same trouble?

http://www.circuitbreakerservice.com/images/THQP120.jpg


Be kind to your neighbor, he knows where you live

Work Gear for Electricians and the Trades
Re: another fire hazard panel [Re: Niko] #196846 10/29/10 04:27 PM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline
Cat Servant
Member
There are, believe it or not, different types of 'shorts.' Sometimes there is enough impedance - arcing is a high-impedance type of fault - that a breaker may respond slowly.

As for the 30-amp load, the question is: how long was the load applied? Breakers trip faster the greater the overcurrent condition.

Still, everything in this world shows variations in quality, and wear out / break down with time. Maybe you have a bad breaker - but that's no reason to suspect an entire product line.

Re: another fire hazard panel [Re: renosteinke] #196848 10/29/10 06:04 PM
Joined: Jun 2006
Posts: 613
M
mikesh Offline
Member
A 15 amp circuit breaker is tripping on a time curve until around 38 amps where it starts to react in it's instantaneous range.
As a rule of thumb you need 6 to 8 times the rated current to trip any circuit breaker and most fuses in less than 8 cycles (instantaneous trip)
A 15 amp breaker will carry 135% or its rating for around an hour or about 20 amps.
So how long did you apply a %100 overload?

Then there are loose set screws, loose bonding terminals, and other bad connections that can add impedance to the fault path which can create sustained faults in the many minutes range where good connections might trip a breaker faster. Imagine your fault path is the EMT and several set screws are not tightened or worse the pipe separates. 8 ohms is enough resistance to allow a 15 amp breaker to feed a fault as if it was a load and the breaker never trips. Can you start a fire with 1800 watts? Sorry I will stop now as it is becoming a lecture.

Re: another fire hazard panel [Re: mikesh] #196850 10/29/10 06:38 PM
Joined: Apr 2002
Posts: 7,233
HotLine1 Offline
Member
Years back I had heating issues with a batch of GE 'Thin' single pole CBs. They originated in Mexico, and could have been the first batch from a GE plant relocation.

Returning the batch for replacements was no hassle at the then local GE Supply. Replacements were USA origin, at my insistance.

As Mikesh said, other issues could lead to a non, or long trip.



John
Re: another fire hazard panel [Re: renosteinke] #196854 10/29/10 06:57 PM
Joined: Aug 2006
Posts: 356
Niko Offline OP
Member
Quote
As for the 30-amp load, the question is: how long was the load applied? Breakers trip faster the greater the overcurrent condition.


I left it on for about a minute.

Re: another fire hazard panel [Re: Niko] #196856 10/29/10 07:07 PM
Joined: Apr 2002
Posts: 7,233
HotLine1 Offline
Member
Niko:
IMHO, a minute was not long enough. If you want to spend some time, contact a GE company/factory rep and inquire IF they have any interest in testing or disecting that baby.

If it's a fairly new CB they may have a vested interest in checking it out.



John
Re: another fire hazard panel [Re: HotLine1] #196860 10/29/10 07:16 PM
Joined: Aug 2006
Posts: 356
Niko Offline OP
Member
The place is about 40 years old and so are the breakers.


Be kind to your neighbor, he knows where you live


Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Tom
Tom
Shinnston, WV USA
Posts: 1,044
Joined: January 2001
Show All Member Profiles 
Top Posters(30 Days)
MCosta 3
Popular Topics(Views)
275,509 Are you busy
209,408 Re: Forum
196,796 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3