JonInNY Show full post »
JonInNY
Thank you Skip, for your detailed and informative answer.

Jon
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techntrek
SkipD;36591 wrote:
I agree with Dan. It's also a good idea to never either open or close a breaker with significant loads (especially loads having a significant inductive load such as a motor) turned on. Switching a breaker's position with no current flowing through it is MUCH easier on the breaker than switching a load with it. This is even more important when the breaker is something like your main disconnect because those are not only hard to repair but are expensive to replace.


If you don't have a whole-house genset you don't need to open the main breaker, just the circuit breaker that feeds the genset sub-panel. Just pointing this out for those that have them.
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techntrek
MacL;36560 wrote:

Some techs will only do this by opening the MCB, so that the Normally used contacts (utility) are not separated hot, as pitting will occur from the arc on on the contacts that you rely on 99.99% of the time. These contacts are usually dead when they are separated.


When the house is transferred back to utility after the outage is over, the utility contacts will arc.
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redman
I agree and disagree with the turning the main breaker off.
Every year when I service a generator, I turn / switch the main breaker off, either 60 / 70 / 100 / 150 / 200 or 400 amps and do a full test on house to simulate a utility power outage. This is the only way to know if everything is going to work as it should during a power outage.
I carry a spare breakers in my service truck for this, in case for some reason, it didn't want to switch back or the "handle" part of the breaker was to break off.
With that said, I'm very Thank full I have never had to replace one yet, and hope I never do.
If a homeowner calls and wants to check his generator with bad weather coming, I have him turn off all the loads in electrical panel before turning off the transfer switch, just for safety reasons, but if he / she doesn't know how to do that, just have them turn off the main.
I suggest just starting the generator up let it run 10 minutes, then shut off, put back in auto and don't worry about it.
My personal generator, I test every month under load conditions for 30 minutes, turning off the main, its a 43900 and 15 years later still no problems.
Mike
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JonInNY
redman;36604 wrote:
I agree and disagree with the turning the main breaker off.
Every year when I service a generator, I turn / switch the main breaker off, either 60 / 70 / 100 / 150 / 200 or 400 amps and do a full test on house to simulate a utility power outage. This is the only way to know if everything is going to work as it should during a power outage.
I carry a spare breakers in my service truck for this, in case for some reason, it didn't want to switch back or the "handle" part of the breaker was to break off.
With that said, I'm very Thank full I have never had to replace one yet, and hope I never do.
If a homeowner calls and wants to check his generator with bad weather coming, I have him turn off all the loads in electrical panel before turning off the transfer switch, just for safety reasons, but if he / she doesn't know how to do that, just have them turn off the main.
I suggest just starting the generator up let it run 10 minutes, then shut off, put back in auto and don't worry about it.
My personal generator, I test every month under load conditions for 30 minutes, turning off the main, its a 43900 and 15 years later still no problems.
Mike


That sounds like great advice! Thanks!
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JonInNY
Push to Trip vs Turning CB Off?

So, I'm getting ready to run a full test on the system, and I noticed the CB on the transfer switch has a "Push to Trip" button.

That would lead me to believe that it's meant to be used as a test. But is it better to use this button, or to just push the CB down to the off position? Or does it not matter?
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BrentB
Had someone push that test button once, had to bypass the whole system until a new breaker was shipped! We never use that for a test! Just turn the main off.
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Skip Douglas SkipD
NOTE: I've moved all the posts about air conditioner crankcase heaters to its own thread. The OP mentioned that this thread was morphing into another subject. The new thread is in the "Offtopic Chat" area and is called "[URL="http://zillerstore.com/forums/showthread.php?t=3922"]Air conditioner compressor heaters[/URL]".

Let's try to keep this thread on topic, please. :)
Skip Douglas
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MacL
techntrek;36597 wrote:
When the house is transferred back to utility after the outage is over, the utility contacts will arc.


Yes, they could. But there is no way to avoid this. Does not follow that you should add avoidable arcing because there is one that is unavoidable.

The arc that may be created on closing is far smaller than the one created on separation.



These switches are a piece of junk, I rebuilt one yesterday.
State your problem, not your diagnosis.
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nrp3
Transfer mechanism went?
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MacL
nrp3;36634 wrote:
Transfer mechanism went?


Occasionally one of the utility contacts would not make contact and the owner would lose lights in half his house. Sensing is between the circuit breaker and the contacts so the generator did not start.

I had a contactor on my truck, but he did not want to spend $600. So we did some filing and shimming to lower the upper stationary contact. But the moving contact sure could press against the stationary contacts with more pressure than they do. He's an ac man, and after disassembling the contactor, he was not impressed with the construction either.
State your problem, not your diagnosis.
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Skip Douglas SkipD
MacL;36635 wrote:
Occasionally one of the utility contacts would not make contact and the owner would lose lights in half his house. Sensing is between the circuit breaker and the contacts so the generator did not start.

I had a contactor on my truck, but he did not want to spend $600. So we did some filing and shimming to lower the upper stationary contact. But the moving contact sure could press against the stationary contacts with more pressure than they do. He's an ac man, and after disassembling the contactor, he was not impressed with the construction either.
Just to make sure - I assume you are referring to contact problems with the transfer contactor and not the disconnect breakers in the ATS. Is this correct? If so, then the best thing I can think of to do when testing the generator cycling would be to turn off any heavy loads prior to a controlled test transfer and that would apply for both directions of transfer.
Skip Douglas
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JonInNY
SkipD;36636 wrote:
Just to make sure - I assume you are referring to contact problems with the transfer contactor and not the disconnect breakers in the ATS. Is this correct? If so, then the best thing I can think of to do when testing the generator cycling would be to turn off any heavy loads prior to a controlled test transfer and that would apply for both directions of transfer.


So maybe a good way to simulate the outage (although this is not what would happen during a real outage) would be to kill the house main breaker, turn off the transfer switch CB allowing generator to start up, and then turn on the house CB again, therefore applying a load?
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Skip Douglas SkipD
JonInNY;36637 wrote:
So maybe a good way to simulate the outage (although this is not what would happen during a real outage) would be to kill the house main breaker, turn off the transfer switch CB allowing generator to start up, and then turn on the house CB again, therefore applying a load?
That's not what I would do. You're risking burning the contacts in the main disconnect. That's a lot more expensive (and more difficult) to repair than individual breakers that get their contacts burned.

I would turn off individual loads by whatever means is best. By "best", I am thinking of methods to remove loads that would not risk un-necessary use of relay contacts or circuit breaker contacts. For example, I would turn off the air conditioner by simply dealing with the thermostat settings. I would turn off the well pump by waiting until it was off and then turning off the individual breaker for it. If I had an electric stove or water heater, I would simply turn them off with their controls. I would turn off any truly significant lighting loads by using the associated light switches.
Skip Douglas
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JonInNY
SkipD;36638 wrote:
That's not what I would do. You're risking burning the contacts in the main disconnect. That's a lot more expensive (and more difficult) to repair than individual breakers that get their contacts burned.

I would turn off individual loads by whatever means is best. By "best", I am thinking of methods to remove loads that would not risk un-necessary use of relay contacts or circuit breaker contacts. For example, I would turn off the air conditioner by simply dealing with the thermostat settings. I would turn off the well pump by waiting until it was off and then turning off the individual breaker for it. If I had an electric stove or water heater, I would simply turn them off with their controls. I would turn off any truly significant lighting loads by using the associated light switches.


Got it!
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nrp3
I had a 200 amp unit go about a month ago the same way, half utility missing. Changed the mechanism in this case. It would be nice if all the lugs were included, it would avoid some extra work.
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techntrek
On the flip side, years ago I wired my TS so I could control it to manually shut down the Generac overnight during long outages. No issues with mine. But, I also have efficient loads on during transfer and don't have the big loads on (water heater, well pump).
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Hodgy
.

Good discussion on this thread.

I have been around for a while and never heard so much discussion and warnings about throwing CB's. At first I thought it was just the CB in the transfer switch that was everyones concern.

As the discussion goes on it appears that all CB's should not be thrown under load. I thought that is why we have CB's and not screw in fuses.

What am I missing ?


.
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techntrek
I've worked in multiple buildings, back in the 80's and 90's, where one or more circuit breakers were used as switches for lighting. Warehouses and a retail store.
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Hodgy
techntrek;36651 wrote:
I've worked in multiple buildings, back in the 80's and 90's, where one or more circuit breakers were used as switches for lighting. Warehouses and a retail store.




With no problems ?



.
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John R
Hodgy;36652 wrote:
With no problems ?



.


Your right, it will not hurt them to be switched off, or on.
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techntrek
On/off daily. But based on earlier discussion here that is ok if it is rated HID or SWD (depending on the type of lighting).
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UPS
Hodgy;36643 wrote:
.
As the discussion goes on it appears that all CB's should not be thrown under load. I thought that is why we have CB's and not screw in fuses.
What am I missing ?

techntrek;36651 wrote:
I've worked in multiple buildings, back in the 80's and 90's, where one or more circuit breakers were used as switches for lighting. Warehouses and a retail store.

SkipD;36638 wrote:
You're risking burning the contacts in the main disconnect. That's a lot more expensive (and more difficult) to repair than individual breakers that get their contacts burned.

The larger breakers have heavy spring tension, and need a significant amount of effort to move them. They are very rarely moved and it's very likely more than half are never turned off or trip in their lifetime. The manufacturers don't have to worry much about the effect of heavy use.
Small breakers are commonly used for light control in businesses and also are expected to trip occasionally. They have to be built with that in mind. And it takes about 5 minutes to replace one.
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MacL
SkipD;36636 wrote:
Just to make sure - I assume you are referring to contact problems with the transfer contactor and not the disconnect breakers in the ATS. Is this correct? If so, then the best thing I can think of to do when testing the generator cycling would be to turn off any heavy loads prior to a controlled test transfer and that would apply for both directions of transfer.


Yes the transfer contacts. Heat and wear sometimes makes them not make contact.

Yes I like to have as little current flowing as possible, and then I pull a fuse.

But as a tech, I cannot recommend that people do what I do. I don't want them welding tools to the inside of their switch.

I have customers telling me to pull the fuse on the CP before I change the battery. Or offering me funnels. If I had 5 cents for each piece of advice I get....
State your problem, not your diagnosis.
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