Raring to go but got questions

Boerman · April 2009

OK, so I took the plunge. Ordered a Selsam SuperTwin, which is due to arrive Friday. Got a tower built: 35' tilt up made of 4" high carbon steel pipe; will be guyed on 4 sides @ 20' and 30' with 1/4' cables. Got plenty of 10-3 wire and conduit to run 3' underground to the house. Not sure when the inverter will get here, but it is a Windy Boy 3000US.

Now, I just want to make sure I have all the right ideas. I am out in the country so I don't have to worry too much about local building codes and inspectors and such. But still, I would prefer not to burn my house down. I am pretty good at most things and like to do things for myself. I have done basic wiring around the house and barn, but I want to make sure that I am not missing anything.

Coming off the turbine, I have wild 3 phase. That will go into a rectifier to convert to DC, from there out to the inverter. Somewhere along the way I know that I will need a disconnect, no problem. But it is tying to the grid that makes me nervous.

From the grid side, I have a meter. Out from there to a main disconnect. From there it goes to the load center in the house. Question number one is: can I shut off the main disconnect and tie into the lugs on the house-side and then just turn the main back on? Or plan B, there is another wire coming out from that main disconnect that goes to a seperate smaller disconnect and from there to the area where my water heater is. I replaced the electric water heater a couple of years ago with a tankless water heater. At that time I put in a small breaker box there because the tankless needed 240v and the service there was only 120v, so I had to run the new wire there. So, same thing really: can I shut off the breaker going to that breaker box and tie in from the inverter at the lugs there?

All my life I have been taking juice OUT of the lines. Somehow the idea of putting more IN makes me a bit nervous. Somehow I have a picture in my mind of me flipping the switch and hearing a big pop and seeing sparks flying and all the houses down the road going dark. Can anyone point anything out to me in my ideas above that might cause a problem? ......or disaster?

My other question is somewhat related. People talk about shorting out the 3 phase to stop the turbine. All my life, short circuit and shorting out and just about anything using the word "short" in connection with electricity was considered bad. And I must say, over the years working on cars and around the house, there have been times when a wire or a screwdriver has made a contact that shouldn't have been made and the effects were impressive.....and sometimes a bit scary. So, taking a couple of kilowatts and shorting them out just has this bad sound in my ears. I have s 60amp double pole AC disconnect to use for this purpose. I figure, each of the 3 phases go to a post with another wire connecting the two bottom posts together. Then the "off" position is actually "on" for the turbine. So, when I throw the breaker to "on", all 3 phases should be shorted together, right? Fireworks? Smoke? Or is that the actual right way for it to work?

Inquiring minds want to know.

Thanks

icarus · April 2009

Re: Raring to go but got questions

You may be out of the range of building inspectors,,, but I suspect that you are not out of the range of electrical inspectors,,, and rightly so.

Any grid tie connection NEEDS to be done with the approval of the utility! I can't comment on your nuts and bolts issue,,but without doing everything right,, with the proper installation techniques (and understanding of why!) you risk not only your property,, but the life and safety of your neighbours and any utility lineman who happens to be working on your system!

"All my life I have been taking juice OUT of the lines. Somehow the idea of putting more IN makes me a bit nervous. Somehow I have a picture in my mind of me flipping the switch and hearing a big pop and seeing sparks flying and all the houses down the road going dark. Can anyone point anything out to me in my ideas above that might cause a problem? ......or disaster?"

This paragraph tells me that you need to get competent on site advice,,,imho.

Tony

mike95490 · April 2009

Re: Raring to go but got questions

1) we want photos when it goes up.

2) Check witht he mfg about how to shut down, if it's ok to short the outputs to ground, or not. I think they use modified automotive alternators on the Selsams, I don't know if they allow shorting, or if they do something with the field coil or what.
mfg-url: http://dualrotor.com/

3) grid-tie-in - you HAVE to get with your electric company, It's not quite as simple as red wire here, blue wire there, and stop writing checks.

Boerman · April 2009

Re: Raring to go but got questions

Thanks for your reply. I understand your concerns and, for the most part, agree with them. But it is the "nuts and bolts" issues that I am concerned with right now. In some ways, I feel forced into doing most, if not all , of this work myself. The only person/company that I know of in this area that is familiar with wind energy sells Skystream turbines and isn't interested in working on any system that he doesn't sell himself. His system is more than double the cost of mine.

With the anti-islanding feature of the inverter, I don't see how I would pose a potential danger to the grid or to my neighbors. The comments I made in that regard were more tongue-in-cheek emphasis on the fact that I want to be cautious. If the grid goes down for any reason, I will be automatically turned off.

I don't want to seem argumentative here, but I don't see a lot of installation technique involved here. You disconnect power by throwing the breaker switch. Unscrew the lugs, insert the wires, screw the lugs back in and turn the power back on. If that is the case, why should I pay someone else $50 an hour to do something that I can do myself?

What really is driving me to do it myself is the power company. When I first started thinking about doing this, I called them up and spoke with one of their engineers. Oh yes, they allow customer RE setups and are required by law to do net metering. OK, so I get a little closer to being able to afford the project, so I call them again to get more specifics about what will be required of me. An extra meter. OK, I get that($8.50 a month) and anti-islanding protection. That's all, they said. Great. So I order (and pay for) all the stuff. So I call them again- I'm getting close to being ready to install. So they want to send me the necessary paperwork. Great! We'll be in business soon.

But when I actually GOT the paperwork it was easy to see why they are so much in favor of green energy. The charge for the extra meter, no problem. But they want $25 a month to READ that meter. I have three other meters on my place. Do they charge $25 a month each to read those meters??? NO! Then there is a $40 a month "standby" charge. WHAT???? Well, just in case I don't produce all the electricity I need, they are "standing by" to provide what I need. THEY ARE ALREADY THERE!! It's not like they are sending a truck with a few extra barrels of electricity. If I close up the house and turn everything off and go on vacation for six months, are they "standing by"? Yes. Are they charging me $40 a month for standing by? NO!

They SAY they are for green energy. But they are trying to make it prohibitively expensive.

So, I don't want to do net metering. I don't want to put any electricity back into their system. I doubt that I will ever produce more than I am using. But even if I do, they can have it. free. I don't want to mess with them or their meters.

And please don't anyone suggest off-grid. I know about off-grid and it isn't going to work in my situation.

mike95490 · April 2009

Re: Raring to go but got questions

When you first asked about net metering, you likely got a "flag" on your account. If your usage drops more than some threshold (10% ?) they will likely come out to inspect your meter, and if they discover it connected to RE, they will likely just cut you off, and wait for you to beg them to take your money.
We forget, the Utility is King.

BB. · April 2009

Re: Raring to go but got questions

Note: I am not a licensed electrician or solar installer. The suggestions below are how I understand the basic requirements of the code--but I certianly may have made one or more mistakes--so it is incumbent on the reader/installer to ensure that all local code and safety conditions are met. Please ask questions--there are others here with more experience that I that can help too.

I agree that the standard GT Inverter is a pretty safe device.

Most of the issues/questions about Inverter/Utility Feed safety has been around people looking to connect a standard Off-Grid inverter to their grid, or the accidents that happened when people connected generators to utility power (improperly wired) and did some real damage.

The biggest issues with GT Inverters (which your wind turbine includes internally) is the wiring into the house (building) breaker panel and grounding of the system/installation.

The issue around wiring/breaker box is the total current supplied to the breaker plus the current from the Wind Turbine...

Normally, for example, say you have a 100 amp rated box. And you have a 100 amp main feed/breaker coming in. If you where to connect an alternate power source (say your 20 amp 240 VAC GT inverter). Then the box would have 120 amps of current available, and its ratings would be exceeded.

So, either you would need to install a (for example) 200 amp box with 100 amp (or whatever) breaker + the 20 amp GT service breaker--or use the NEC alternative which allow you to power up to 125% of the box load with an external GT power source. So:

120% of 100 amp box = 120 amp maximum in sources

100a breaker + 20a breaker = 120 amps so below NEC limit.

Now, when you install the 20A GT breaker--you need to look at the bus bar arrangement internal to the Box. If your 100 amp feed is from the top, then the 20 Amp GT breaker needs to be installed at the bottom... That way, no portion of the Bus bar will see more than 100 amp total load (all feeds will "tap" current from the "mid point" of the bar--100 amps from one end, 20 amps from the other--in a worst case condition).

Regarding what your utility is doing to you--Does not sound nice--but they are just following the regulations that the State PUC and their local engineers/business managers put on their system.

The reservation charge--that is typically something we see in California associated with business accounts... Roughly 1/2 the bill is kWhr billing, and the other 1/2 is (if I recall correctly) your peak 15 minute of use in the last year (or what you have paid to reserve for wiring, transformers, distribution circuits, etc.).

Normally, home systems do not have that charge (it is really rolled into the base rate charges).

The other issue is a reservation / leaving the grid charge for supplying power with your own generator--in theory, the state and utility have built systems based on an expected customer base. If "you" leave the system and go off-grid -- then "you" are expected to pay for "stranding" the generator capacity that the PUC / Utility bought "with your name on it".

Is this stuff fair--probably is if you are a utility trying to make money selling power--and not acting like a giant unpaid battery bank with no revenue stream for use of the battery (back-feeding the mains while the GT is active, using "your generated" energy when the GT is not active.

I will end it here other than to say you might talk with your PUC and Utility about the extra "unfair" charges that may violate state and federal laws encouraging "green power"... But, it would probably be difficult to win that one in court.

A better tack may be to offer to be a "demonstration project" for green power in your neighborhood and say they can get some free publicity / green cred (using equipment paid for by you).

Also, watch out for the "meters"... The old mechanical ones are pretty straight forward (turn forward, you pay; turn backwards, you get credits--unless there is a one-way pawl on the disk).

See if you can convince them to give you a meter that only "turns forwards" and say you will let them keep any excess (may or may not do this)--that would be great--but they do not have any incentive to do this (you are reducing your billable power needs--with no upside for the Utility).

But, as a warning, some meters, apparently may charge you for the pleasure of placing power into the grid (by the way they are programmed--don't know that this is true--but it was reported somewhere I had read before). Either as a penalty--or just they always "turn forward" even if the power is going "backwards" to the grid.

I don't know if any way you can connect a "pure GT Inverter" to your home/business that would never back-feed the grid (could be done--but nobody I have heard of makes a commercial Listed product that has this capability).

Your alternative (and I know you said no batteries/off grid) is to look at the Xantrex XW Hybrid GT/Off-Grid system. You would need ~400 AH of batteries @ 48 volts to support a 6kW GT/Hybrid inverter.

It may (I believe that older Xantrex/Trace products could) be able to be programmed to never drive power back to the grid... So, legally, there may not be anything the power company could to with such a system...

However, you would need to convert your Wind System to DC charging @ 48 volts (not impossible--but not cheap/easy either) and install the XW system (and get off-grid / emergency power too). It would also support solar PV and backup generator too--if you wanted same.

I will stop here as I am going off point for you.

Questions/comments/suggestions?

-Bill

boB · April 2009

Re: Raring to go but got questions

If you have the space, and it sounds like you do... Raise that turbine up high ! 30 feet isn't all that high up.

Just a suggestion.

boB

dwh · April 2009

Re: Raring to go but got questions

Boerman wrote: »

I don't want to seem argumentative here, but I don't see a lot of installation technique involved here. You disconnect power by throwing the breaker switch. Unscrew the lugs, insert the wires, screw the lugs back in and turn the power back on. If that is the case, why should I pay someone else $50 an hour to do something that I can do myself?

Perhaps because they took the time to learn the National Electical Code - and you didn't?

Homepower magazine has a nice little online feature to search their past articles. There is a guy, John Wiles, who writes a column called "Code Corner". Most of his articles apply to solar systems, but where he talks about grid-tie and the NEC should apply to what you are doing.

Here's an article that might be useful to you:

http://www.homepower.com/article/?file=HP111_pg94_CodeCorner

EDIT:

P.S. I think it doesn't get mentioned enough, and perhaps most people don't even realize it - but the NEC is written and maintained by the National Fire Prevention Association.

http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70

icarus · April 2009

Re: Raring to go but got questions

Just as an aside,, and I'm sure it is going to generate it's share of heat but here goes anyway,,

I would like to see a bit less Utility bashing. Are there utilities out there that do everything they can to squeeze a nickel out of customers no matter what? Probably. Are many utility rules arcane and useless? Probably. Are there utilities that have less than zero interest in promoting RE/green energy because they see that as a threat to their profit structure? Probably. Are there other ways that I can point the figure,, sure.

On the other hand there are lots of utilities and utility workers that work hard every day to keep the lights on in all kinds of crazy weather. When it gets right down to it,,, grid power is one of the true miracles of the 20th century. Just read the posts from other parts of the world to see how remarkable and reliable it is.

The reality is that we have enjoyed cheap (every cheap) power for generations,, and courtesy of the REA/BPA, Provincial Hydro authorities etc,, even quite remote sites (not mine!) have turn key power. One of the costs that has come with this cheap power is the relative cost effectiveness of PV/RE power. Because grid power is so cheap,,, it makes it hard to make RE pay.

So when you have a complaint about the pricing structure of your utility remember what they really bring you. When you have a complaint about a perceived abuse,, contact your local PUC, or in the matter of a "public" utility,, contact your elected reps.

Finally, as we have so often said on this forum,, if you are trying to install RE to save money over grid power your dreaming,,,

Tony

dwh · April 2009

Re: Raring to go but got questions

BB. wrote: »

So, either you would need to install a (for example) 200 amp box with 100 amp (or whatever) breaker + the 20 amp GT service breaker--or use the NEC alternative which allow you to power up to 125% of the box load with an external GT power source. So:

125% of 100 amp box = 125 amp maximum in sources

100a breaker + 20a breaker = 120 amps so below NEC limit.

-Bill

Um...sorry, but I don't believe this is quite right.

The busbar 125% exception is for loads - for feeds it's only 120%. (And either one only applies to residential, they aren't allowed in commercial.)

The conductors and the backfeed breaker do have to be sized at 125% of the inverter output though, and the breaker has to be listed for backfeed use.

BB. · April 2009

Re: Raring to go but got questions

Thank you -- I did not remember if it was 125% or 120%...

-Bill

Raring to go but got questions

Comments

Categories