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Joined: Jul 2004
Posts: 787
L
Member
Quote
All factory post mortems stated failure of the electronic trip portion of the breaker. They were all more cost effective to replace v.s. rebuild. All breakers are 10 years old and are in a clean, temperature comtrolled environment.


Having no experience with large Circuit Breakers, may I still introduce some ideas?

How do the trip modules receive power? Is it possible that the control power source is providing "dirty" power which results in failure of the trip modules?

Is the "clean, temperature comtrolled environment" the area where the switchgear is installed, not necessarilly the environment of the trip modules? If so, could the modules see significantly higher temperatures due to outside air being introduced thru unused conduits or floor penetrations?

Larry C

Joined: Jan 2005
Posts: 5,445
Likes: 2
Cat Servant
Member
Good point, Mikesh ... I had forgotten how things can fly about during a major fault.

Joined: Nov 2005
Posts: 827
Likes: 1
J
Member
HE,
I'm a little bummed out at you for dribbling out the most critical info: A HISTORY OF FAILED TRIP UNITS IN THE SAME LINE-UP!!!! What's up with that? It's a ton of you-know- what that replacing the trip units should cost more than installing new breakers! Especially when one of their folks should be doing it, on site, with minimal cost to your customer. And did you press them for the exact failures in the trip units? A bad run of electrolytics? Tantalum caps in backwards? At the price you're paying, you deserve specifics! Did you happen to put your high-end analyzer on the breaker control power?

The more I think about this the more ticked off I get. You know that test isn't a real test, and that your trip unit is likely shot! You just want your customer up and running with a potentially deadly work-around. Do you think any peceived blessings from us would let you sleep any better at night if this situation broke badly? I'm sorry if I have you pegged wrong but I've been down this road before!
People leave out vital info to justify doing something that they already know they shouldn't!
Joe

Joined: Jan 2005
Posts: 91
H
Member
Joe, I can assure you that I don’t come to this site for anyone’s blessings and I take full responsibility for any actions that I take regardless of where I get advice. I posted here because I respect the opinions of those that share this site. To me the synergy that’s created by their collective minds is truly a valued resource. I also appreciate the level of professionalism and mature tone that I typically find here as opposed to other forums. Since I was uncertain about how effectively I’ve been/am dealing with this I came here. My intent was to get any and all thoughts regarding this situation, nothing more.

Joined: Nov 2005
Posts: 827
Likes: 1
J
Member
OK, I'll take your word for it. Here is my opinion! That place should have at least one spare feeder breaker that is of a common amp frame and maximum amp trip used in your line-up. It could be racked in in place of a flaky breaker with the trip settings dialed down as appropriate for the substituted breaker.
Joe

Joined: Sep 2004
Posts: 68
H
Member
Square D/Group Schneider has had a history of certain lines of electronic low voltage breakers (SE series etc.) failing and little factory support for repair. Their approach is to offer new at grossly inflated prices. The problem with these breakers is almost always the electronics. It certainly causes their customers to look at other manufacturers for future equipment upgrades. Part of the reason for this approach is that specifiers and purchasing agents look primarily at initial cost when buying for new installation or upgrade. Very little consideration is given to total lifetime cost and reliable factory support at a reasonable rate. All the manufacturers therefore respond to this business model in the same way-competitive initial pricing, inflated prices and no repair parts later.

Joined: Jan 2005
Posts: 91
H
Member
Homer,

Based on my experiences with this I'd have to say that you're dead on. I also wonder if the manufacturers not openly taking responsibility for defective breakers is due to concerns about liability for the lost customer revenue that result from related production shutdowns. I know of a few contractors in this area that have landed on the wrong end of this type of law suit when their work has been suspected of causing similar losses. This is somewhat similar to a delay of progress claim in the construction world.

Last edited by Helectric; 09/10/08 10:18 AM. Reason: Spelling :)
Joined: Nov 2005
Posts: 827
Likes: 1
J
Member
http://www.etc-12.com/trip-units/sqd-amptector-trip-unit.html

What about somebody else's trip unit? I'm not vouching for this company's product because I just found them via Google. If a company makes crap and won't stand behind it, they deserve to get retrofitted out of the market. If the mechanicals of your breakers are sound, seek out another trip unit. Better yet, ask your Square D rep who's aftermarket trip unit he or she reccommends. Maybe you'll get better treatment.
Joe

Joined: Oct 2008
Posts: 1
M
New Member
Larry,

Regarding your question about where the retrofit trip modules receive power: They receive their power from breaker side CTs.

Faulty trip units should be your #1 concern. NETA recently did a study that suggested that 1/4 breakers that are currently in-service have faulty trip units installed. I believe for the most part, this study was based on 600V air circuit breakers with older dash-pot style trips installed.

Having nearly 100 breakers reach our shop on a monthy basis, we have observed #'s higher than NETA's 1/4. We noticed that nearly 50% of molded/insulated case breakers and approximately 30-40% of air breakers have faulty trip units installed.

Kind of scary.

Last edited by MattBrierley; 10/06/08 09:55 AM.
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