| |
| 07 May 2008 02:48:34 |
| David Williams |
| power and tiebreakers |
Hello, Can anyone give me information on the purpose of a tiebreaker that is found in switchgear power distribution? This is more of an electrical than electronic question but I could not find an electricicity newsgroup. Meaning, in a typical building, you have power that comes from the street and goes into switchgear, then a transformer, then a feeder panel that has a tiebreaker switch there. As I understand it, if you have two feeders into a system, and one feeder fails, the tiebreaker switch opens up so that bad/faulty electricity from the bad feed cannot flow through the sysem until it is safe. That is about all I know. Anybody have any resources I can read on this? Thanks, David |
| 07 May 2008 08:52:38 |
| JeffM |
| Re: power and tiebreakers |
David Williams wrote: >This is more of an electrical than electronic question but >I could not find an electricicity newsgroup. > The majority of Usenet is archived and is quite searchable. >Can anyone give me information on the purpose of a tiebreaker >that is found in switchgear power distribution? > http://groups.google.com/groups/search?q=switchgear+electrical+-jobs |
| 07 May 2008 10:42:56 |
| Paul Hovnanian P.E. |
| Re: power and tiebreakers |
David Williams wrote: > > Hello, > Can anyone give me information on the purpose of a tiebreaker > that is found in switchgear power distribution? > This is more of an electrical than electronic question but > I could not find an electricicity newsgroup. > > Meaning, in a typical building, you have power that comes > from the street and goes into switchgear, then a transformer, then > a feeder panel that has a tiebreaker switch there. > > As I understand it, if you have two feeders into a system, > and one feeder fails, the tiebreaker switch opens up so that > bad/faulty electricity from the bad feed cannot flow through the sysem > until it is safe. That is about all I know. > > Anybody have any resources I can read on this? > > Thanks, > > David A tie breaker (bus tie breaker) or switch is used to connect busses together that are normally fed from independent sources. This is usually done when performing maintenance on one of the sources so it can be taken off line and the loads on its bus may be powered through the tie breaker. There are also some situations in which busses may be paralleled in normal operation (tie breaker and both feeds closed), but it is necessary to provide a means to disconnect one of the busses from the other in the event of a fault. -- Paul Hovnanian paul@hovnanian.com ----------------------------------------------------------------------- Procrastinators: The leaders for tomorrow. |
| 07 May 2008 13:37:18 |
| Silver Surfer |
| Re: power and tiebreakers |
In a power plant, tie breakers are commonly supplied. Normally the tie breaker is open. If the normal feed to a bus trips or is otherwise unavailable the tie breaker can be closed to connect the unpowered bus to a companion bus that does have power available from its own normal source. In some instances the tie breaker will close automatically unless there has been a fault on the dead bus itself. Care must be taken not to overload the source that is supplying two buses when the tie breaker is closed. "David Williams" <dw149@acmex.gatech.edu > wrote in message news:fvr5a2$aju$1@news-int2.gatech.edu... > Hello, > Can anyone give me information on the purpose of a tiebreaker > that is found in switchgear power distribution? > This is more of an electrical than electronic question but > I could not find an electricicity newsgroup. > > Meaning, in a typical building, you have power that comes > from the street and goes into switchgear, then a transformer, then > a feeder panel that has a tiebreaker switch there. > > As I understand it, if you have two feeders into a system, > and one feeder fails, the tiebreaker switch opens up so that > bad/faulty electricity from the bad feed cannot flow through the sysem > until it is safe. That is about all I know. > > Anybody have any resources I can read on this? > > Thanks, > > David |
| 07 May 2008 12:23:58 |
| mpm |
| Re: power and tiebreakers |
On May 7, 1:42=EF=BF=BDpm, "Paul Hovnanian P.E." <pa...@seanet.com > wrote: > David Williams wrote: > > > Hello, > > Can anyone give me information on the purpose of a tiebreaker > > that is found in switchgear power distribution? > > This is more of an electrical than electronic question but > > I could not find an electricicity newsgroup. > > > Meaning, in a typical building, you have power that comes > > from the street and goes into switchgear, then a transformer, then > > a feeder panel that has a tiebreaker switch there. > > > As I understand it, if you have two feeders into a system, > > and one feeder fails, the tiebreaker switch opens up so that > > bad/faulty electricity from the bad feed cannot flow through the sysem > > until it is safe. =EF=BF=BDThat is about all I know. > > > Anybody have any resources I can read on this? > > > Thanks, > > > David > > A tie breaker (bus tie breaker) or switch is used to connect busses > together that are normally fed from independent sources. This is usually > done when performing maintenance on one of the sources so it can be > taken off line and the loads on its bus may be powered through the tie > breaker. > > There are also some situations in which busses may be paralleled in > normal operation (tie breaker and both feeds closed), but it is > necessary to provide a means to disconnect one of the busses from the > other in the event of a fault. > > -- > Paul Hovnanian =EF=BF=BDp...@hovnanian.com > ----------------------------------------------------------------------- > Procrastinators: The leaders for tomorrow.- Hide quoted text - > > - Show quoted text - Ch-4 (TV) in Miami went off the air for about an hour once because someone had the bright idea to tie the UPS in separate from the generator. Utility power goes out, runs on UPS. (20 minutes run time reserve) Generator won't start. UPS dies. Generator finally started (after some effort), BUT the UPS would not release the tie until it recharged. Long story short: Main, UPS and Generator - and there the station was sitting in the dark. Unbelievable. |
| 07 May 2008 15:39:30 |
| Michael A. Terrell |
| Re: power and tiebreakers |
mpm wrote: > > Ch-4 (TV) in Miami went off the air for about an hour once because > someone had the bright idea to tie the UPS in separate from the > generator. > > Utility power goes out, runs on UPS. (20 minutes run time reserve) > Generator won't start. UPS dies. > Generator finally started (after some effort), BUT the UPS would not > release the tie until it recharged. > > Long story short: Main, UPS and Generator - and there the station was > sitting in the dark. > Unbelievable. In Miami? I believe it. Aren't all the electricians members of the IBEW? -- http://improve-usenet.org/index.html Use any search engine other than Google till they stop polluting USENET with porn and junk commercial SPAM If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm |
| 07 May 2008 23:59:39 |
| legg |
| Re: power and tiebreakers |
On Wed, 7 May 2008 12:23:58 -0700 (PDT), mpm <mpmillard@aol.com > wrote: > >Ch-4 (TV) in Miami went off the air for about an hour once because >someone had the bright idea to tie the UPS in separate from the >generator. > >Utility power goes out, runs on UPS. (20 minutes run time reserve) >Generator won't start. UPS dies. >Generator finally started (after some effort), BUT the UPS would not >release the tie until it recharged. > >Long story short: Main, UPS and Generator - and there the station was >sitting in the dark. >Unbelievable. If you've got a dead syatem, there has to be a manual procedure and hardware present to allow manual over-ride of the dead hardware. When a UPS is configured, it's important to determine who's on first. RL |
| 08 May 2008 07:40:15 |
| mpm |
| Re: power and tiebreakers |
On May 7, 3:39=EF=BF=BDpm, "Michael A. Terrell" <mike.terr...@earthlink.net >= wrote: > =EF=BF=BD =EF=BF=BDIn Miami? =EF=BF=BDI believe it. =EF=BF=BDAren't all th= e electricians members of the > IBEW? Hey Mike! I could probably come up with some smart-ass acronym for "IBEW" that includs all the relevant racial (latin/cuban/south american) slurs, but I'm afraid my Spanish is just too rusty... :) Although perhaps no longer contained to just South Florida, when exactly does "Immigration" become an "Invasion"? -mpm |
| 08 May 2008 12:02:18 |
| Michael A. Terrell |
| Re: power and tiebreakers |
mpm wrote: > > On May 7, 3:39�pm, "Michael A. Terrell" <mike.terr...@earthlink.net> > wrote: > > > � �In Miami? �I believe it. �Aren't all the electricians members of the > > IBEW? > > Hey Mike! > > I could probably come up with some smart-ass acronym for "IBEW" that > includs all the relevant racial (latin/cuban/south american) slurs, > but I'm afraid my Spanish is just too rusty... :) My problem with the IBEW and Miami was all the shoddy work done on fairly new homes that their members wired just before Hurricane Andrew. The buiding inspectors who let them get by with the bad work were all long gone, as well That, and their sleazy attempt to try to get the techs at one place I worked to join their ranks. They promised me less than I was making, per hour, less vacation time, less benefits, and wanted several thousand a year for the privilege, then they called me a liar when I told them what I was already getting. Needless to say, all the techs just laughed in their faces. > Although perhaps no longer contained to just South Florida, when > exactly does "Immigration" become an "Invasion"? -mpm When done without proper paperwork. -- http://improve-usenet.org/index.html Use any search engine other than Google till they stop polluting USENET with porn and junk commercial SPAM If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm |
| 08 May 2008 09:06:36 |
| Richard Henry |
| Re: power and tiebreakers |
On May 8, 9:02=C2=A0am, "Michael A. Terrell" <mike.terr...@earthlink.net > wrote: > mpm wrote: > > > On May 7, 3:39=EF=BF=BDpm, "Michael A. Terrell" <mike.terr...@earthlink.= net > > > wrote: > > > > =EF=BF=BD =EF=BF=BDIn Miami? =EF=BF=BDI believe it. =EF=BF=BDAren't al= l the electricians members of the > > > IBEW? > > > Hey Mike! > > > I could probably come up with some smart-ass acronym for "IBEW" that > > includs all the relevant racial (latin/cuban/south american) slurs, > > but I'm afraid my Spanish is just too rusty... =C2=A0:) > > =C2=A0 =C2=A0My problem with the IBEW and Miami was all the shoddy work do= ne on > fairly new homes that their members wired just before Hurricane Andrew. > The buiding inspectors who let them get by with the bad work were all > long gone, as well. =C2=A0 A better electrical insatllation would have made the houses more resistant to the hurricane? |
| 08 May 2008 13:01:48 |
| Michael A. Terrell |
| Re: power and tiebreakers |
Richard Henry wrote: > > On May 8, 9:02 am, "Michael A. Terrell" <mike.terr...@earthlink.net> > wrote: > > mpm wrote: > > > > > On May 7, 3:39�pm, "Michael A. Terrell" <mike.terr...@earthlink.net> > > > wrote: > > > > > > � �In Miami? �I believe it. �Aren't all the electricians members of the > > > > IBEW? > > > > > Hey Mike! > > > > > I could probably come up with some smart-ass acronym for "IBEW" that > > > includs all the relevant racial (latin/cuban/south american) slurs, > > > but I'm afraid my Spanish is just too rusty...  :) > > > >   My problem with the IBEW and Miami was all the shoddy work done on > > fairly new homes that their members wired just before Hurricane Andrew. > > The buiding inspectors who let them get by with the bad work were all > > long gone, as well.  > > A better electrical insatllation would have made the houses more > resistant to the hurricane? Sigh. Are you really that stupid? Well, you DO use Google groups... No, the hurricanes revealed the substandard work done by the same people who insisted that only union members could do it right. -- http://improve-usenet.org/index.html Use any search engine other than Google till they stop polluting USENET with porn and junk commercial SPAM If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm |
| 08 May 2008 13:50:12 |
| mpm |
| Re: power and tiebreakers |
On May 8, 12:02=EF=BF=BDpm, "Michael A. Terrell" <mike.terr...@earthlink.net= > wrote: I hear you loud and clear, Michael. But that's what you get when contractors can't read the plans because the plans are in English. For that matter, the permitting & zoning dept doesn't speak English either, so I guess they have no choice but to rubber stamp whatever's put in front of them.? Or possibly (and this is the truly scary alternative...) that quality of construction is actually considered a vast improvement over what they're used to "back home". Hell, I know an AM station in Mexico that uses modified, welded shovel heads for their electric disconnect. (I am not kidding!!) True story: I actually got "escorted" out of Dade Co. Permitting & Zoning once because 6 months after the hurricane, we could not get a simple 60-amp agricultural drop to power an emergency radio tower & shelter we had erected in the hours following the hurricane. They actually claimed the installation was "illegal" because we hadn't pulled a permit for the temporary electric - and they refused to even talk to us until that was remedied. Hello!! The department was closed for weeks after the storm! And the backlog was so bad afterwards, we couldn't get in, even when they did open up! We were actually doing them (and Dade Co residents) a favor by waiting. By that time, we had roughly 110kW of generator, and only needing about 30, gave the rest to the military - which promptly set up a 24- hour, armed command and control center right on the site. It's not like we were hurting.... In fact, we were also providing antenna space on this same tower for Miami-Dade Fire Rescue and Dade Co. Emergency Services. Free of charge, I might add. But I digress.. Anyhoo, after the rough treatment by Dade Co., and being advised we actually had to take the temporary tower & electric down (even though the original tower had not yet been reconstructed), I placed just one call. It was to US Marshall Service (who coincidentally, were tenants on the temporary tower seeing as it was the only one still standing!). The very next day, they arrived at Dade Co. P&Z and informed both the Chief Electrical Inspector and the P&Z Director that they had their choice of going to jail right then and there, or they could issue the temporary permit. (I guess a 3rd option would have been for Code Enforcement to try to get past the military...?) We had our permit that afternoon. And for the record, I don't think they were waiving those handcuffs in Spanish. (Actually, I wasn't there for all this, but I heard about it.) It still took another 2 months for FPL to get permanent power out there!! But now that the "invasion" is over, I'm wondering if we should have called INS back then instead? :) And that was in '92. Can you imagine how bad it must be now? Oh, and lest I forget.... People do not realize just how bad a hurricane can be. Cat-3 and above for sure.... Evacuate! |
| 08 May 2008 17:09:36 |
| Michael A. Terrell |
| Re: power and tiebreakers |
mpm wrote: > > On May 8, 12:02�pm, "Michael A. Terrell" <mike.terr...@earthlink.net> > wrote: > > I hear you loud and clear, Michael. > But that's what you get when contractors can't read the plans because > the plans are in English. > For that matter, the permitting & zoning dept doesn't speak English > either, so I guess they have no choice but to rubber stamp whatever's > put in front of them.? > > Or possibly (and this is the truly scary alternative...) that quality > of construction is actually considered a vast improvement over what > they're used to "back home". > > Hell, I know an AM station in Mexico that uses modified, welded shovel > heads for their electric disconnect. (I am not kidding!!) Mexico? I would have expected worn out disk brake drums, with pieces of rope to pull them out.. > True story: I actually got "escorted" out of Dade Co. Permitting & > Zoning once because 6 months after the hurricane, we could not get a > simple 60-amp agricultural drop to power an emergency radio tower & > shelter we had erected in the hours following the hurricane. They > actually claimed the installation was "illegal" because we hadn't > pulled a permit for the temporary electric - and they refused to even > talk to us until that was remedied. Hello!! The department was > closed for weeks after the storm! And the backlog was so bad > afterwards, we couldn't get in, even when they did open up! We were > actually doing them (and Dade Co residents) a favor by waiting. > > By that time, we had roughly 110kW of generator, and only needing > about 30, gave the rest to the military - which promptly set up a 24- > hour, armed command and control center right on the site. It's not > like we were hurting.... Good for you. I heard that most of the emergency equipment at Homestead Air Force Base was damaged during the storms. I have a friend who ran Dad County's radio shop before Andrew. He retired and moved to north central Florida as soon as the roads were clear. > In fact, we were also providing antenna space on this same tower for > Miami-Dade Fire Rescue and Dade Co. Emergency Services. Free of > charge, I might add. But I digress.. > > Anyhoo, after the rough treatment by Dade Co., and being advised we > actually had to take the temporary tower & electric down (even though > the original tower had not yet been reconstructed), I placed just one > call. That sounds like me, when engineering refused to sign off on an ECO. :) > It was to US Marshall Service (who coincidentally, were tenants on the > temporary tower seeing as it was the only one still standing!). > > The very next day, they arrived at Dade Co. P&Z and informed both the > Chief Electrical Inspector and the P&Z Director that they had their > choice of going to jail right then and there, or they could issue the > temporary permit. (I guess a 3rd option would have been for Code > Enforcement to try to get past the military...?) It would have been fun to watch, as they were hauled away in handcuffs in the back of a military vehicle to the nearest military holding cell. I don't know if anything was available at Homestead. They would have probably sent them to Eglin Air Force Base in the Florida the panhandle. Hopefully they could have found a case of Korean war surplus rations and canned water to make sure they never wanted to go back. > We had our permit that afternoon. > And for the record, I don't think they were waiving those handcuffs in > Spanish. > (Actually, I wasn't there for all this, but I heard about it.) > > It still took another 2 months for FPL to get permanent power out > there!! That doesn't surprise me, either. Progress energy had a crew on my street today to inspect power poles for damage from the hurricanes a couple years ago. > But now that the "invasion" is over, I'm wondering if we should have > called INS back then instead? :) And that was in '92. Can you > imagine how bad it must be now? From what I hear, if you don't speak spanish, you don't want ot get near Dade county. :( > Oh, and lest I forget.... > People do not realize just how bad a hurricane can be. > Cat-3 and above for sure.... Evacuate! I rode out the last one in an emergency shelter for the disabled at a high school near my home. Talk about poor planning. A lot of people were diabetic, and most of those were on insulin, but they didn't think to provide refrigeration. When we located a small refrigerator in a teacher's break room, school board employees promptly arrived to remove it, putting a lot of people's lives in danger. -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida |
| 09 May 2008 20:00:40 |
| Paul Hovnanian P.E. |
| Re: power and tiebreakers |
mpm wrote: > [snip] > Ch-4 (TV) in Miami went off the air for about an hour once because > someone had the bright idea to tie the UPS in separate from the > generator. > > Utility power goes out, runs on UPS. (20 minutes run time reserve) > Generator won't start. UPS dies. > Generator finally started (after some effort), BUT the UPS would not > release the tie until it recharged. > > Long story short: Main, UPS and Generator - and there the station was > sitting in the dark. > Unbelievable. Not really. I was involved in the repairs to a (supposedly) redundant power system in a companies critical data center. Someone had installed some bolts in panelboard buses incorrectly and they were in danger of overheating. It turned out that these bolts (and the associated panelboards) were single point failure locations that could take the entire data center down. Nobody could figure out how to de-energize even one source and panel at a time to perform the repairs. The whole data center had to be shut down for several days. -- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ Relax, its only ones and zeros! |
| 10 May 2008 10:48:16 |
| JosephKK |
| Re: power and tiebreakers |
On Wed, 7 May 2008 12:23:58 -0700 (PDT), mpm <mpmillard@aol.com > wrote: >On May 7, 1:42?pm, "Paul Hovnanian P.E." <pa...@seanet.com> wrote: >> David Williams wrote: >> >> > Hello, >> > Can anyone give me information on the purpose of a tiebreaker >> > that is found in switchgear power distribution? >> > This is more of an electrical than electronic question but >> > I could not find an electricicity newsgroup. >> >> > Meaning, in a typical building, you have power that comes >> > from the street and goes into switchgear, then a transformer, then >> > a feeder panel that has a tiebreaker switch there. >> >> > As I understand it, if you have two feeders into a system, >> > and one feeder fails, the tiebreaker switch opens up so that >> > bad/faulty electricity from the bad feed cannot flow through the sysem >> > until it is safe. ?That is about all I know. >> >> > Anybody have any resources I can read on this? >> >> > Thanks, >> >> > David >> >> A tie breaker (bus tie breaker) or switch is used to connect busses >> together that are normally fed from independent sources. This is usually >> done when performing maintenance on one of the sources so it can be >> taken off line and the loads on its bus may be powered through the tie >> breaker. >> >> There are also some situations in which busses may be paralleled in >> normal operation (tie breaker and both feeds closed), but it is >> necessary to provide a means to disconnect one of the busses from the >> other in the event of a fault. >> >> -- >> Paul Hovnanian ?p...@hovnanian.com >> ----------------------------------------------------------------------- >> Procrastinators: The leaders for tomorrow.- Hide quoted text - >> >> - Show quoted text - > >Ch-4 (TV) in Miami went off the air for about an hour once because >someone had the bright idea to tie the UPS in separate from the >generator. > >Utility power goes out, runs on UPS. (20 minutes run time reserve) >Generator won't start. UPS dies. >Generator finally started (after some effort), BUT the UPS would not >release the tie until it recharged. > >Long story short: Main, UPS and Generator - and there the station was >sitting in the dark. >Unbelievable. A PE that could not be bothered to check the NEC should have been sued. See Articles 700, 701, and 702 would be a good start. |