What Voltage?

[iwire]

Re: What Voltage?

I will give you the code rules and you can make up your own mind as to what you want to do.

Remember if you choose to ignore the code and something happens you will be in a bad position to defend yourself. Everyone wants electric work on the cheap, you as the electrician have to explain the rules to them.

ARTICLE 702 Optional Standby Systems

I. General

702.1 Scope.
The provisions of this article apply to the installation and operation of optional standby systems.

The systems covered by this article consist of those that are permanently installed in their entirety, including prime movers, and those that are arranged for a connection to a premises wiring system from a portable alternate power supply.

702.6 Transfer Equipment.
Transfer equipment shall be suitable for the intended use and designed and installed so as to prevent the inadvertent interconnection of normal and alternate sources of supply in any operation of the transfer equipment. Transfer equipment and electric power production systems installed to permit operation in parallel with the normal source shall meet the requirements of Article 705.

Transfer equipment, located on the load side of branch circuit protection, shall be permitted to contain supplementary overcurrent protection having an interrupting rating sufficient for the available fault current that the generator can deliver. The supplementary overcurrent protection devices shall be part of a listed transfer equipment.

Transfer equipment shall be required for all standby systems subject to the provisions of this article and for which an electric-utility supply is either the normal or standby source.

Forget about an ATS go with MTS (manual transfer switch) they are much cheaper.

 

[peter d]

Re: What Voltage?

I agree, a manual transfer panel (aka Gentran) is the way to go. I bought mine at Home Depot for $50 on clearance. They normally cost $200, which is a small price to pay for safety.

As others have said, if all else fails, run some heavy duty extension cords and plug things in.

 

[jwelectric]

Re: What Voltage?

Originally posted by peter d:
I agree, a manual transfer panel (aka Gentran) is the way to go. I bought mine at Home Depot for $50 on clearance. They normally cost $200, which is a small price to pay for safety.

As others have said, if all else fails, run some heavy duty extension cords and plug things in.

Here is the best advice you could be given for a quick fix to the storm problem.

Once a homeowner sees how to back feed a breaker he will try it his self the next time and forget the main.

 

[bensonelectric]

Re: What Voltage?

Just hypothetical of course, but if you did manage to backfeed into the utility, would your meter run backwards?

 

[physis]

Re: What Voltage?

It's actually done on purpose sometimes but I think you have to have a deal with the utility and a meter that allows it.

Edit: I left out three words that time.

[ July 10, 2005, 12:35 AM: Message edited by: physis ]

 

[hurk27]

Re: What Voltage?

And the fact that the generator would have to be in sync with the 60hz of the utility, Most mechanical meters will run backward. I have accidentally plugged a few in upside down and they do run backward but If you don't have a special line break that de-energizes from the utility in the event of a power failure, And a agreement with the POCO you could get into big trouble with them if you start showing less watt hours then the month before? I don't think the electronic one will do this. And I know there is a Fedral law that does require the POCO to buy back any extra power you produce.

So there is much more to this then just hooking up a generator to back feed the utility.

 

[bensonelectric]

Re: What Voltage?

Im not interested in cheating the POCO, I am more interested in the inner workings of how a meter works. I am tempted to take apart a spare one at school.

 

[apauling]

Re: What Voltage?

This is not a an assertion of fact, but I was told by a lineman a long time ago that if the generator is on when the power comes on, there is the possibility that the panel could blow up. I don't understand what would happen to a conductor when two voltages that are out of phase and polarity with each other are present on the same wire. I understand phased and stacked signals riding on a a sine wave, but not this situation.

curious, paul

 

[charlie]

Re: What Voltage?

However that would be rare (still possible) for it to back feed into an open line, more likely this small generator would be trying to power at least some of the neighbors. This would most likely overload the generator and trips its breaker.

Bob, this is not true but I don't understand why it isn't true. Tests have been done with small generators for out linemen that show a generator tied into the secondary and back feeding to the primary with load on the secondary and the primary still having 13.2 kV on it.

Our primary is 13.2 kV but I have seen 12,470, 13,200, and 13,800 in the 15 kV class. Some have dabbled in 23 kV and 34.5 kV for distribution voltages. We also have some 4160 volt primary left that has not been converted to 13.2 kV.

[ July 10, 2005, 07:10 AM: Message edited by: charlie ]

 

[iwire]

Re: What Voltage?

Originally posted by charlie:

However that would be rare (still possible) for it to back feed into an open line, more likely this small generator would be trying to power at least some of the neighbors. This would most likely overload the generator and trips its breaker.

Bob, this is not true but I don't understand why it isn't true. Tests have been done with small generators for out linemen that show a generator tied into the secondary and back feeding to the primary with load on the secondary and the primary still having 13.2 kV on it.

Thats unexpected, even more reason to use proper transfer equipment.

 

[George Stolz]

Re: What Voltage?

Originally posted by southernboys:
I have a question as to if I pull the meter then hook the generator would this be considered safe? What if I unhook the feeder to my main then hook the generator to the main breaker would this be ok?

Why do you think it would be slower to install a manual transfer switch than these permanent solutions to temporary problems?

Around here, the POCO would most likely getted p'ed if people starting ad-hoc pulling meters. Somebody has to go back through, inspect and re-tag the meters, creating labor on the POCO's part immediately after a natural disaster that's probably taxing their resources as it is.

Originally posted by southernboys:
Guys I know its a shortcut and no I dont like doing it one stinking bit.

Then don't do it. It will take as little time to do it the right way, as it would to do it the wrong way.

...but I know theres at least one company out there doing it the shortcut way and this is my best opportunity to get my company jumpstarted. Hate to use a crisis to do this however Id rather me do it then some out of towner charging 500 to hook up a generator or 5000 to hook up a powerpack

Don't fret about what hacks do. Worry about your own reputation and the safety of your clients, and the linemen who serve them.

Hope I have not alienated myself in this forum as it has been a hugh help. Thanks for the strong advice

Better to ask and get perspective, then to quietly fall in line with the hacks and create dangers that could hurt someone.

If someone gets hurt, or if equipment starts blowing up, then your reputation will be at risk, and lawsuits would likely be pending.

Dangerous subjects entail strong advice. You're always welcome to ask the dangerous questions.

Be safe!

 

[bensonelectric]

Re: What Voltage?

While at the local POCO's training facility we learned to use hotsticks to disconnect the transformer from the HV line ect, and one of the linemen, explained to us that this is actually a real danger to them because it is more common than most people think and VERY possible.

 

[hardworkingstiff]

Re: What Voltage?

southernboys,

Are you a licensed electrical contractor?

 

[southernboys]

Re: What Voltage?

stiff yes I am. And so are the hacks out there. I was trying to keep homeowners from killing linemen. The hacks that are hooking thru meter are also licensed its scary how others operate but thats not me and thats why I wouldnt have hooked up the generators after recieving this advice. I will now go to lowes and buy a few mts thanks for the advice again

 

[LarryFine]

Re: What Voltage?

I'm stunned at the ignorance even where there is no excuse.

I just got back from the local Lowe's, where a couple were buying a portable 7.5KW generator for power outages. I gave them a business card and offered our services for installing a transfer switch and power inlet.

They were asking about using the cord that came with the unit, and I suggested cutting off the four receptacle ends and replacing them it with a cord receptacle end compatible with the t/s they would select.

The husband said he had a 240v. receptacle box in the garage, and he would make a double-plug cord and just shut off the main breaker. When I mentioned that it's illegal to do, he said, "That depends on where you are." :roll:

When I said that I would never do that for a customer and explained the danger if someone forgets the main, he replied, "I know what I'm doing; I work for the power company!" I was floored, and just walked away.

 

[physis]

Re: What Voltage?

I have a new saying now.

It's ok to do stupid stuff as long as you think you're qualified.

Edit: I changed it.

[ July 10, 2005, 06:34 PM: Message edited by: physis ]

 

[peter d]

Re: What Voltage?

Originally posted by LarryFine:

When I said that I would never do that for a customer and explained the danger if someone forgets the main, he replied, "I know what I'm doing; I work for the power company!"

 

[hardworkingstiff]

Re: What Voltage?

Originally posted by LarryFine:

"I know what I'm doing; I work for the power company!"

Instructions (and codes) are for people that don't know what they are doing.

 

[jimwalker]

Re: What Voltage?

Actually what would happen if main was left on is that the 240 would backfeed the transformer to full primary voltage and then feed all the others transformers.Likely hood is a very much overloaded generator.But with voltage drops being involved its a guess as if the generator trips its own breaker.You are creating a very unfair risk to the linesmen that are trying to help you.The problem with just turning the main off is the human factor of messing up and forgetting.

 

[charlie]

Re: What Voltage?

We do have a problem with people who think they can "handle" electricity just because the work for the power company. We have a line department but that is a small part of the whole company. Consider all of the people who work in the generating stations, offices, mechanical and electrical departments, garage, I.T. areas, management, storerooms, etc. I assure you that a lineman didn't say that.