Generator backfeeding into utility lines

[955Lincoln]

Interesting, I don't completely understand what's going on there, but the guy seems pretty confident he knows what he's doing.

JB.

Basically, pure water is not conductive. It is the impurities, chemicals, salt, and so forth that make it conductive. Take for instance high power water cooled transmitter tubes. The tube's plate is submerged in water and it has many thousands of volts on it.

 

[JB4310]

Here's another clip, this one shows two Cat generators being load tested with a salt water tank. A bit more intimidating than the other video...this setup is @440 volts and 640 kilowatts. It gets interesting at 1:20 or so:

Generator Load Test. - YouTube

:thumbsup:

Yeah, all I could think about was a Frankenstein movie

Looks like a standard test procedure for those big gensets.

I just plug in some electric heaters to load test mine

JB

 

[955Lincoln]

If you want to feed your whole panel you will need a service rated transfer switch, they are twice the cost of a standard double pole-double throw knife blade switch.

Could you educate me about the differences of these 2 switches please? I will be hooking up a new service in the near future and need to start researching what I need to buy. If both are rated for the same amperage is the one still twice the cost? I always thought a transfer switch was just a DPDT device.

 

[BobRip]

So this poses a whole new question. With the number of people who now have some form of green power (solar, wind, etc.) that at any point in time can feed power back into the grid at any point in time I can't see how any lineman would ever work on a line without protecting themselves first.

I think that have a device that detects the connection to the utility. If the utility is not sending power they shutdown automatically. Solar systems cannot operate independently from the grid unless they have batteries and auto disconnect. This is my understanding. Please let me know if I am wrong.

 

[timswi]

Not sure about your neck of the woods, but here in pacific northwest...illegal. The utility companies will shut off and lock out the power if they find out you have it wired illegally until its fixed. They are always sending out notices asking people to fix illegal wiring, They will even inspect the installations for free and recommend mitigation issues. Its real easy to spot most perminant mount units

The only warnings we ever get is to tell us not to run the generator inside the house.

Sounds like your utility companies provide an additional service, that doesn't exist here.

 

[JB4310]

Basically, pure water is not conductive. It is the impurities, chemicals, salt, and so forth that make it conductive. Take for instance high power water cooled transmitter tubes. The tube's plate is submerged in water and it has many thousands of volts on it.

Ok, I'm getting an education here

Interesting. As far as shock hazard goes, then why is it worse to be standing on a damp concrete floor lets say barefoot as opposed to a dry concrete floor? There is a greater shock hazard with the wet floor isn't there???

JB

 

[955Lincoln]

Ok, I'm getting an education here

Interesting. As far as shock hazard goes, then why is it worse to be standing on a damp concrete floor lets say barefoot as opposed to a dry concrete floor? There is a greater shock hazard with the wet floor isn't there???

JB

When I say pure water I mean pure. Something that doesn't normally exist unless the water is processed and filtered like deionized, distilled, very clean and pure.

 

[crazyal]

Ok, I'm getting an education here

Interesting. As far as shock hazard goes, then why is it worse to be standing on a damp concrete floor lets say barefoot as opposed to a dry concrete floor? There is a greater shock hazard with the wet floor isn't there???

JB

You're now talking about the electrical resistance of your skin. Dry skin is something like 500x the resistance of wet skin. Would a dry salt have the same resistance as salt water? If I remember correctly dry salt is an insulator.

 

[crazyal]

I think that have a device that detects the connection to the utility. If the utility is not sending power they shutdown automatically. Solar systems cannot operate independently from the grid unless they have batteries and auto disconnect. This is my understanding. Please let me know if I am wrong.

Their is a code that covers disconnecting from the grid applies to all forms of self generated power. By code you are required to have an automatic disconnect if the grid goes down. Solar panels will work just fine without power from the grid. All they require is sunlight. One of the advantages of solar panels is that if you loose grid power you still have electricity from your panels (during daylight hours and limited by the amount of power your panels can produce of course).

My point was that if a weekend warrior who thought he knew electricity decided to add a wind turbine or solar panel to go green and didn't know the code covering the potential of sending power back into the grid is there. Some power companies require you to sign a form saying you have the correct equipment and some inspect it. However a weekend warrior who thinks he's doing his part for the planet may never even think about any of this.

 

[Tractor Seabee]

Could you educate me about the differences of these 2 switches please? I will be hooking up a new service in the near future and need to start researching what I need to buy. If both are rated for the same amperage is the one still twice the cost? I always thought a transfer switch was just a DPDT device.

The code requires that any device used with the service equipment be "service rated". It has a higher ground fault capacity that the individual branch circuits. If you do know what all this means take my word for it as it is too technical for this forum. So if you are doing the switch selecting of either utility power and generator power at the main breaker level "whole house system" then that is the service entrance. I am trying to make a "licensed electrician" knowledge level something you can understand. It is all about your safety. If you have a sudden fault to ground things can virtually explode and cause a fire or worse if you are in front of it.

This dialog is very important to understand when dealing with heavy commercial/industrial applications or things such as large pumps and compressors.

A more recent issue is arc fault protection. You will encounter this if you do a new installation or major retrofit such as your panel replacement. All bedroom circuits now have to have arc fault circuit breakers. There is a lot to know in the electrical business. It is not for novices.

Of course you all by now should know about ground fault devices in circuits, either at the breaker or the outlet. That is discussion for a different forum as this one also should be.

Ron