Main Nuisance Tripping - Electrician Talk - Professional Electrical Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY, IT'S FREE!
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Forum > General Electrical Discussion


Like Tree4Likes
  • 1 Post By NJWVUGrad
  • 1 Post By Paulusgnome
  • 1 Post By brian john
  • 1 Post By MechanicalDVR
Reply
 
Thread Tools Display Modes
Old 01-25-2018, 03:56 PM   #1
Senior Member
 
Join Date: May 2011
Location: NJ
Posts: 471
Rewards Points: 320
Default Main Nuisance Tripping

Just curious, how often do you see tripped main breakers on new installs where the EC forgot to adjust the trip units from factory min settings?

It seems to happen on projects I am involved with (design) all the time, these things aren't new. At a minimum change the Long time setting to what is on the drawings - if you don't know the rest submit an RFI.

Rant over
MechanicalDVR likes this.
NJWVUGrad is offline   Reply With Quote
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free!

ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

Join ElectricianTalk.com - Click Here JOIN FOR FREE


Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Advertisement
 
Old 01-25-2018, 04:26 PM   #2
Senior Member
 
Join Date: Dec 2010
Location: So.Cal.
Posts: 3,556
Rewards Points: 7,051
Default

Maybe you should attach a big red note to the drawings.
joebanana is offline   Reply With Quote
Old 01-25-2018, 06:18 PM   #3
Senior Member
 
Join Date: Mar 2009
Location: Christchurch, New Zealand
Posts: 179
Rewards Points: 195
Default

This makes me remember a customer at one of my former employers who was a distributor of switchgear.
The customer was a gent from Fiji who was known to us as someone who did not read written instruction, so I spent some time to generate pictorial instructions for the set of air circuit breakers that he was purchasing for use in a sugar mill on one of the outlying islands.
About 3 months after the circuit breakers had been delivered, we got a call from our customer who was quite peeved that the circuit breakers which were now installed in the sugar mill were tripping whenever the mill machinery operated.
The circuit breakers had been supplied with the trip units set to 0.6 x rating. I asked him if they had read the instructions that we provided and got a long silence over the phone and the reluctant admission that they hadn't even made it out of their envelope.
I got to talk the sugar mill electrician through the setup over the phone, he thought it was hilarious.
MikeFL likes this.
Paulusgnome is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 01-25-2018, 07:38 PM   #4
Senior Member
 
Join Date: May 2011
Location: NJ
Posts: 471
Rewards Points: 320
Default

Lol...I have placed in it notes, brought it up in construction meetings, still happens.

And every time someone throws a sh*tfit trying to figure out who to blame.

IMO it should be the first RFI an EC sends if it is not on the drawings.

The issue is that at the time of design - the engineer does not always know what make/model of MCB will be provided and what settings it will have . Some jobs we donít even see a submittal.
NJWVUGrad is offline   Reply With Quote
Old 01-26-2018, 12:06 AM   #5
Senior Member
 
brian john's Avatar
 
Join Date: Mar 2007
Location: Gilbert's Corner VA
Posts: 29,911
Rewards Points: 1,594
Default

There should be an Arc Flash Study and a Coordination Study.

Minimum setting for MOST GFPE relays (not on CB's) is 100 amps Instantaneous or .1 seconds.

As a general rule of thumb the GFPE should be set at 400 amps this gets you above the trip setting of most 20 and 30 amp CB's.

But we do not adjust unless there is something from an engineer.

On new construction, we suggest leaving set at minimum settings to minimize damage from ground faults
glen1971 likes this.
__________________
Ah, but I was so much older then, I'm younger than that now
brian john is offline   Reply With Quote
Old 01-26-2018, 08:53 AM   #6
Senior Member
 
Join Date: Oct 2012
Location: Alberta Rockies
Posts: 2,716
Rewards Points: 3,790
Default

I was working for an engineering firm and got called to a recently completed job where the main had tripped. I got there and saw that the trip settings were at the minimum. The building owner was there and not happy that his shop was in the dark and no one could work. I told him that the breaker was not properly set and was at the minimum settings. He was an engineer, and doubted what I told him, because he figured the breakers didn't leave the factory set at the minimum settings and I was just an electrician and he was an engineer. He called a testing company that sent a tech to adjust the trip settings. When he asked for the coordination study, they looked at me, and I said, it was never done as it was removed as a cost savings. The owner had forgotten about that one...

Most other jobs I've seen they usually get set during commissioning by either me or a testing company, using the settings on the single line, or by a separate document from the electrical engineer.
glen1971 is offline   Reply With Quote
Old 01-26-2018, 09:25 AM   #7
Old Grumpy Bastard
 
MechanicalDVR's Avatar
 
Join Date: Dec 2007
Location: "Old Dominion"
Posts: 59,300
Rewards Points: 1,016
Default

Quote:
Originally Posted by glen1971 View Post
I was working for an engineering firm and got called to a recently completed job where the main had tripped. I got there and saw that the trip settings were at the minimum. The building owner was there and not happy that his shop was in the dark and no one could work. I told him that the breaker was not properly set and was at the minimum settings. He was an engineer, and doubted what I told him, because he figured the breakers didn't leave the factory set at the minimum settings and I was just an electrician and he was an engineer. He called a testing company that sent a tech to adjust the trip settings. When he asked for the coordination study, they looked at me, and I said, it was never done as it was removed as a cost savings. The owner had forgotten about that one...

Most other jobs I've seen they usually get set during commissioning by either me or a testing company, using the settings on the single line, or by a separate document from the electrical engineer.
Figure an 'engineer' would have realized you can't cut out certain parts of a job like that.
glen1971 likes this.
__________________
I'm as Christian as possible in the times we live in.

Always just a stallion in a china shop
MechanicalDVR is online now   Reply With Quote
Old 01-26-2018, 12:16 PM   #8
Senior Member
 
Join Date: Mar 2015
Location: Alberta
Posts: 1,003
Rewards Points: 416
Default

We got called to a hotel that was having tripping issues for about 5 years. 2000 A Main tripped whenever someone backed over a parking pedestal. Turned out the main had GF protection that had never been set up. We had to get an engineering outfit to do a coordination study and calculate the proper settings. Good for us bad for hotel.
mitch65 is offline   Reply With Quote
The Following User Says Thank You to mitch65 For This Useful Post:
Bird dog (01-26-2018)
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Main lug only vs. Main breaker panels mikedl361 General Electrical Discussion 21 11-30-2017 12:14 PM
Question about residential main breakers carryyourbooks General Electrical Discussion 21 10-13-2017 09:11 AM
Adding a main disconnect Chevys10zr2 Services and Service Equipment 15 09-06-2017 09:45 PM
Main breaker trips Glock23gp General Electrical Discussion 18 12-10-2016 08:39 PM
2017 NEC 555, minimizing gfi tripping class c PLCs, VFDs, Motors and Controls 4 08-16-2016 08:48 PM


All times are GMT -4. The time now is 04:12 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | HVACSite.com | PaintTalk.com | PlumbingZone.com | RoofingTalk.com