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 Post subject: Adjusting trip settings on energized breaker
PostPosted: Sat Mar 29, 2014 5:27 am 

Joined: Wed Mar 13, 2013 9:12 am
Posts: 12
Recently we had a study done and adjustments were recommended for both arc flash reduction and coordination in the report.
Can adjustments be made to breaker trip settings while energized? Our electrician says yes, he has down it on instantaneous but I am unsure on the other settings recommended like short time delay, etc.


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PostPosted: Sat Mar 29, 2014 9:13 am 
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Location: Wisconsin
In the old days (20-30years ago), many breakers had some problems when you switched between the detents on the dial. It was not unknown for a breaker to forget what it was and act like all the settings were at minimum, as you crossed from one setting to the next (your 1600 breaker just became a 400A one, not good if you are drawing 600A of load).
Today's breaker do not normally experience this problem.

However, the most likely time for a breaker to trip is when you are touching it.


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PostPosted: Mon Mar 31, 2014 3:54 am 

Joined: Mon Dec 29, 2008 9:05 am
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A quick call to the manufacturer or review of the trip unit instructions will most likely indicate the answer is "No".
I have done this exact thing many times on many different types of trip units for various reasons with mixed results.


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PostPosted: Mon Mar 31, 2014 5:34 am 

Joined: Wed Dec 02, 2009 4:46 pm
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Location: CT
Without guidance from the manufacturer I would advice no. Modern CBs should allow changing of the settings on the fly. But it cannot be guaranteed. I represent a CB manufacturer.


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PostPosted: Mon Mar 31, 2014 6:57 am 
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Joined: Tue Jan 19, 2010 2:35 pm
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If I were you, I'd call the breaker manufacturer before doing anything. For example, newer Siemens breakers warn the user (in the manual) not to adjust setting with the breaker energized. ETU745 trip pack is one example. Further, depending on the age of the breaker, ask yourself if it's been switched off in the last few years? People frequently forget to turn off big breakers annually. But be warned, if the breaker hasn't been switched off or has not tripped, you could be in for trouble. We sometimes see broken handles on molded case circuit breakers. My guess is the worker trips the breaker with the trip button and when he tries to reset the breaker, he finds it won't catch. Oh Crap! Now the excitement begins. They really start pushing hard on the handle and sometimes the handle fails. Somehow, they get it reset, but not without some danger and elevated blood pressure.

I'm with some of the other postings, how about getting a solid plan in place with options. try asking "what if" and see where it takes you. Good luck


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PostPosted: Mon Mar 31, 2014 7:07 am 
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Location: Port Huron, Michigan
I have been adjusting several breakers in my current facility while live. You are adjusting the trip relays, not the breaker itself, and as long as the relay doesn't output a trip signal while being adjusted there is no problem. You have to be careful and understand what you are doing and what might happen to the relay while you do it.


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PostPosted: Mon Mar 31, 2014 7:20 am 
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Polar wrote:
Recently we had a study done and adjustments were recommended for both arc flash reduction and coordination in the report.
Can adjustments be made to breaker trip settings while energized? Our electrician says yes, he has down it on instantaneous but I am unsure on the other settings recommended like short time delay, etc.


JBD was spot on, some trip units will default to the lowest setting in between settings, all depends on the model. Have you looked at maintenence switches for arc flash reduction?


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PostPosted: Mon Mar 31, 2014 7:52 am 

Joined: Wed Mar 13, 2013 9:12 am
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Thank you all for your responses. I will push for making the adjustments with the circuit breaker open.

Zog - Some of the adjustments are to improve coordination and others are to reduce arc flash hazard.


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PostPosted: Mon Mar 31, 2014 9:07 am 
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Location: Waggaman - Cornerstone Chemical Company
I have made changes before to electronic motor protection relays while the motor is running, but only for RTDs or an alarm level. I would be hesitant to alter the settings pertaining to current trip levels. As most of the posters suggested, check with the manufacturer.

Unfortunately, these issues (or the unintended results!) are sometimes a career-buster, so be careful. Making changes with the unit open is best.


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PostPosted: Mon Mar 31, 2014 9:27 am 
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Voltrael, you might have adjusted the circuit breakers for medium or high voltage because those circuit breakers requires arc quenching medium and has to operate with relays and many have maintenance mode switch too. But our low voltage static trip or thermal magnetic circuit breakers have inbuilt settings and we have to do the coordination and generate the trip settings using software like SKM, EasyPower, ETAP, etc. Jim taught us to do coordination manually, and we can appreciate how software has revolutionized the industries. For me, no matter what the manufacturer says or PPE I don, I just don't have balls to perform the coordinated trip settings while energized :D
I contact utility, schedule a short time shutdown, put standby/portable generator in manual mode if any (otherwise ATS will call the generator when utility power goes off) and do my stuffs, check it, energize the plant, put the generators to auto mode and hands over the report.


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PostPosted: Mon Mar 31, 2014 12:28 pm 
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Namgay Tshering wrote:
Voltrael, you might have adjusted the circuit breakers for medium or high voltage because those circuit breakers requires arc quenching medium and has to operate with relays and many have maintenance mode switch too. But our low voltage static trip or thermal magnetic circuit breakers have inbuilt settings and we have to do the coordination and generate the trip settings using software like SKM, EasyPower, ETAP, etc. Jim taught us to do coordination manually, and we can appreciate how software has revolutionized the industries. For me, no matter what the manufacturer says or PPE I don, I just don't have balls to perform the coordinated trip settings while energized :D
I contact utility, schedule a short time shutdown, put standby/portable generator in manual mode if any (otherwise ATS will call the generator when utility power goes off) and do my stuffs, check it, energize the plant, put the generators to auto mode and hands over the report.



I was referring to 600V and 2400V equipment.

The 2400V relays we have are actually electromechanical, you take them out of service as one of the steps in changing their settings.

The 600V relays we have are of a few different varieties. Some have rotary dials, and being analog there are no "between" settings. The rest are digital, and you enter a new setting in to replace the existing.

I am doing my coordination at this industrial plant using SKM.


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PostPosted: Tue Apr 01, 2014 5:09 pm 
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If its a safety concern by way of example, even a very advanced microprocessor based relay like one from Basket, ABB, GE, or SEL, is clearly designed to allow diagnostics and reading, and making changes,even by remote or through a centralized database. The manufacturers ALL say that making changes COULD cause a problem. As you can imagine, a fat finger error on CT ratio, or say changing firmware, can definitely have the POTENTIAL to cause an issue, no matter how safe everything is. So they all have a lawyer clause that absconds them of any responsibility. This is the same one that you see for molded case breakers. My advice is that you need to understand the risks and not get locked up in lawyer paranoia. Or if you prefer, quit. Making no decision is the same as making a decision. Taking "no" risks is extremely risky. There are no absolute guarantees beyond death and taxes, and lawyers. The key is an understanding of the risks and taking acceptable ones. There are reputable manufacturers. If you get a bad one (eg GE), move on.


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PostPosted: Tue Apr 01, 2014 8:58 pm 

Joined: Sat Feb 08, 2014 2:54 pm
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Paul, You left off shipping and handling. :)


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PostPosted: Mon Apr 07, 2014 6:16 am 
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JBD wrote:
In the old days (20-30years ago), many breakers had some problems when you switched between the detents on the dial. It was not unknown for a breaker to forget what it was and act like all the settings were at minimum, as you crossed from one setting to the next (your 1600 breaker just became a 400A one, not good if you are drawing 600A of load).
Today's breaker do not normally experience this problem.

However, the most likely time for a breaker to trip is when you are touching it.

Learned that one the hard way about 25 years ago :oops: Was moving a setting from low to high so intuitively it should not have nuisance tripped but.... It was an electronic trip breaker with a bit of hiccup in the first generation of design.

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Brainfiller.com


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