Alternative Power sources - 20KW Generac with 100A or 200A ATS?

Author

20KW Generac with 100A or 200A ATS?

randall.reed@gmail.com

2006-11-21, 5:25 pm

Howdy from Houston everyone...

I purchased a 20KW from Generac today - looking forward to getting it
installed. However I may have made a mistake. I bought the genset
with a 100A ATS with service disconnect to complement a whole house
backup. My question is, should I have purchased the 200A ATS with
service diconnect since my main breaker is 200A? I'm reading and some
people say yes, and others say no...

Please help - I appreciate your opinions and possible experience on the
matter.

Neon John

2006-11-21, 5:25 pm

Since the transfer switch has to handle the whole house load under
normal conditions too, you need the 200 amp one since you already have
200 amp service.

John

On 21 Nov 2006 14:27:31 -0800, randall.reed@gmail.com wrote:

>Howdy from Houston everyone...
>
>I purchased a 20KW from Generac today - looking forward to getting it
>installed. However I may have made a mistake. I bought the genset
>with a 100A ATS with service disconnect to complement a whole house
>backup. My question is, should I have purchased the 200A ATS with
>service diconnect since my main breaker is 200A? I'm reading and some
>people say yes, and others say no...
>
>Please help - I appreciate your opinions and possible experience on the
>matter.
---
John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
Don't let your schooling interfere with your education-Mark Twain

Jens Kr. Kirkebø

2006-11-30, 5:25 pm

On Tue, 21 Nov 2006 17:55:59 -0500, Neon John <no@never.com> wrote:

>Since the transfer switch has to handle the whole house load under
>normal conditions too, you need the 200 amp one since you already have
>200 amp service.

Its quite funny how inefficient the american power grid is. 200A for a
house ? Yikes. That's some _thick_ cables, yes ?
In Sweden they usually have 20A service, but since it's 400V 3-phase
it delivers _more_ power than 200A one-phase 110V...

Solar Flare

2006-11-30, 5:25 pm

Not quite there, Swedey

American power is 200A (can be 60A - 800A) at 120/240 volt supply.
That means two phases at 120 v.

The usual service now is 200A @ 240 volts = 48 kVA

Your service mentioned is 20A x 400V x SQRT(3) = 13.8kVA or about 1/4
the capacity.

The math education in America is also better...LOL

"Jens Kr. Kirkebx" <jkk@scm.no> wrote in message
news:6tjum2tlme76v2a5kq8g3o1svgbn4fimbl@4ax.com...
> On Tue, 21 Nov 2006 17:55:59 -0500, Neon John <no@never.com> wrote:
>
>
> Its quite funny how inefficient the american power grid is. 200A for
> a
> house ? Yikes. That's some _thick_ cables, yes ?
> In Sweden they usually have 20A service, but since it's 400V 3-phase
> it delivers _more_ power than 200A one-phase 110V...

Jens Kr. Kirkebø

2006-11-30, 8:25 pm

On Thu, 30 Nov 2006 17:58:54 -0500, "Solar Flare"
<solaerfart@hootmail.invalidated> wrote:

>American power is 200A (can be 60A - 800A) at 120/240 volt supply.
>That means two phases at 120 v.

Ok, didn't know that. But you still can't run 3-phase motors then, so
why not 3-phase service. For example, geothermal heat pumps most
always have 3-phase compressors. Also big pressure-washers, air
compressors etc.

3-phase 207V seems like the logical choice...

>The usual service now is 200A @ 240 volts = 48 kVA
>
>Your service mentioned is 20A x 400V x SQRT(3) = 13.8kVA or about 1/4
>the capacity.

Correct. I was multiplying with 3 since they use 230V with one of the
phases at a time, but then I should use 230V instead of 400V of
course. Result is the same.

A swede would need a 70A connection for the same power. Still requires
much smaller cables. But it begs the question why one does need 48kW
of power for a house ?!?

I'm from Norway by the way, and here we have 230V 3-phase. The maximum
residential service is 63A which calculates to 25kW. Most houses have
less and we mainly use electricity for heat. My ~2500 square feet
house is all electric and with a 50A connection.

Solar Flare

2006-12-01, 3:25 am

Seems like you have mostly warm weather there then. Most N.Americans
have given up the electric heat idea as it is too expensive compared
to NG. Electric heat was almost impossible with the old 100A service
here. An electric furnace would be 10kW - 25kW alone.

What are your insulation level requirements? In Ontario, Canada the
standard is R20 in the walls and R32 (maybe R40 now) in the ceilings,
last time I looked. Our temp ranges are from 38 c to -30 c and we have
a fair bit of humidity by the Great Lakes.

Larger houses use 400A services but I know of some with bowling alleys
in their basements and elevators to get from floor to floor.

Yes, 3 phase makes motors smaller and much more efficient. Houses do
not use 3 phase generally, as it takes more copper and equipment, if
you are using a 240/400 v wye system. Most of our appliances are 120v
and large units, like A/C, stoves, clothes dryers, take 240v
generally.

"Jens Kr. Kirkebx" <jkk@scm.no> wrote in message
news:fspum29696sqf39h6h6lgsdr23f3arsmpv@4ax.com...
> On Thu, 30 Nov 2006 17:58:54 -0500, "Solar Flare"
> <solaerfart@hootmail.invalidated> wrote:
>
>
> Ok, didn't know that. But you still can't run 3-phase motors then,
> so
> why not 3-phase service. For example, geothermal heat pumps most
> always have 3-phase compressors. Also big pressure-washers, air
> compressors etc.
>
> 3-phase 207V seems like the logical choice...
>
>
> Correct. I was multiplying with 3 since they use 230V with one of
> the
> phases at a time, but then I should use 230V instead of 400V of
> course. Result is the same.
>
> A swede would need a 70A connection for the same power. Still
> requires
> much smaller cables. But it begs the question why one does need 48kW
> of power for a house ?!?
>
> I'm from Norway by the way, and here we have 230V 3-phase. The
> maximum
> residential service is 63A which calculates to 25kW. Most houses
> have
> less and we mainly use electricity for heat. My ~2500 square feet
> house is all electric and with a 50A connection.
>

Jens Kr. Kirkebø

2006-12-01, 3:25 am

On Thu, 30 Nov 2006 23:29:57 -0500, "Solar Flare"
<solaerfart@hootmail.invalidated> wrote:

>Seems like you have mostly warm weather there then. Most N.Americans
>have given up the electric heat idea as it is too expensive compared
>to NG. Electric heat was almost impossible with the old 100A service
>here. An electric furnace would be 10kW - 25kW alone.

We are frequently down to -15C or lower in the winter so it can
certainly be cold. Other parts of the country sometimes have below
-40C. NG is not an option for most as we do not have any gas lines.
Many hoses have been heated with oil but that is changing since even
direct electric heating is cheaper than oil now. Wood is commonly used
though.

Nobody has forced-air furnaces, we never heat air. Electric heat is
either water-delivered, by radiators and in-floor PEX pipes, or by
electric resistance heaters mounted on walls. Also air-air heatpumps
is widely used.

I had an oil-fired boiler but have exchanged it for a geothermal heat
pump. It uses ~2.7kW and delivers ~11kW of heat via the radiators and
in-floor heating. Now I use ~8000kWh for heating and hot water instead
of the ~750 gallons of heating oil I used to use. The cost of 8000kWh
is less than a third of the price for 750 gallons of oil

>What are your insulation level requirements? In Ontario, Canada the
>standard is R20 in the walls and R32 (maybe R40 now) in the ceilings,
>last time I looked. Our temp ranges are from 38 c to -30 c and we have
>a fair bit of humidity by the Great Lakes.

Todays minimum standard is R24 for walls, R32 for floors and R47 for
ceilings. Many use more, up to R47 for floors and walls and R78 for
ceilings. The minimum standard is to be increased soon.

>Larger houses use 400A services but I know of some with bowling alleys
>in their basements and elevators to get from floor to floor.

I wouldn't call that a "house" anymore, sounds more like a mansion.

>Yes, 3 phase makes motors smaller and much more efficient. Houses do
>not use 3 phase generally, as it takes more copper and equipment, if
>you are using a 240/400 v wye system. Most of our appliances are 120v
>and large units, like A/C, stoves, clothes dryers, take 240v
>generally.

More copper ? Well, only the single extra line into your house. As for
equipment, well you need a 3-phase meter. But the 3-phase is split
into 3x1-phase before reaching our wall outlets. Only a few things run
diretcly on 3-phase.

Derek Broughton

2006-12-01, 9:25 am

Jens Kr. Kirkebø wrote:

> On Thu, 30 Nov 2006 23:29:57 -0500, "Solar Flare"
> <solaerfart@hootmail.invalidated> wrote:
>
>
> We are frequently down to -15C or lower in the winter so it can
> certainly be cold. Other parts of the country sometimes have below
> -40C. NG is not an option for most as we do not have any gas lines.

Yes, well that's typical misinformation from Flare. "Most", as in the
largest percentage of the population, probably have access to NG, but the
greater part of Canada and large parts of the US do not. Even in his
neighborhood, we only got gas in a rural area about 15 years ago - and that
was on a main highway; I don't think they ever got gas on the sideroads.
--
derek

2006-12-01, 5:25 pm

In article <fspum29696sqf39h6h6lgsdr23f3arsmpv@4ax.com>,
Jens Kr. Kirkeb? <jkk@scm.no> wrote:

> Ok, didn't know that. But you still can't run 3-phase motors then, so
> why not 3-phase service.

Obviously, this Norseman has never heard of a FreqDrive.... Here in
the USA, when we have Single Phase Power, and need 3 Phase Power, we
just use a FreqDrive instead of a Contactor for Motor Control, and
solve the problem with electronics........

Me isn't technology wonderful.........

Jens Kr. Kirkebø

2006-12-01, 5:25 pm

On Fri, 01 Dec 2006 19:32:58 GMT, Me <Me@shadow.orgs> wrote:

>In article <fspum29696sqf39h6h6lgsdr23f3arsmpv@4ax.com>,
> Jens Kr. Kirkeb? <jkk@scm.no> wrote:
>
>
>Obviously, this Norseman has never heard of a FreqDrive.... Here in
>the USA, when we have Single Phase Power, and need 3 Phase Power, we
>just use a FreqDrive instead of a Contactor for Motor Control, and
>solve the problem with electronics........

Yea, I know you can fix everything with electronics, one can even
rectify the 1-phase and feed it to 3 Outback inverters to make 3-phase
if one wants. But what is the efficiency, and what does a unit that
can deliver 4kW continously cost, for example ?

2006-12-02, 5:25 pm

In article <5711n29t1rqmpmp5a1ksdlcojhhvsh133d@4ax.com>,
Jens Kr. Kirkeb? <jkk@scm.no> wrote:

> On Fri, 01 Dec 2006 19:32:58 GMT, Me <Me@shadow.orgs> wrote:
>
>
> Yea, I know you can fix everything with electronics, one can even
> rectify the 1-phase and feed it to 3 Outback inverters to make 3-phase
> if one wants. But what is the efficiency, and what does a unit that
> can deliver 4kW continously cost, for example ?

Freq Drives are very reasonable in price, and comparable in price
to the same sized Motor Contactor for multi-Horsepower electric
motors. Industrial Plants will buy Freq Drives instead of Contactors
these days, as they get SoftStart, Variable Speed, High Torque, and
Programed Operations for the same price as a contactor, +/- 15%.....

Me

Solar Flare

2006-12-03, 8:25 pm

Contrary to Derek's typical jealousy based response, his interfection
is not true.

While many rural people do not have NG there is a reason for it. The
reason being there is such a small market, being so spread out, there
is no profit in the capitolist market, we enjoy and not likely to be
available. Now when you put this together with some simple logic,
Derek is missing, you discover that most of us Canadians have NG
available to us.

Majority is based upon population and not geographic area. Thw sheer
size of Canada has him overwhelmed from his two up and two down
upbringing.

"Derek Broughton" <news@pointerstop.ca> wrote in message
news:mtk544-c7i.ln1@news.pointerstop.ca...
> Yes, well that's typical misinformation from Flare. "Most", as in
> the
> largest percentage of the population, probably have access to NG,
> but the
> greater part of Canada and large parts of the US do not. Even in
> his
> neighborhood, we only got gas in a rural area about 15 years ago -
> and that
> was on a main highway; I don't think they ever got gas on the
> sideroads.
> --
> derek

Ignoramus22865

2006-12-27, 5:25 pm

On Fri, 01 Dec 2006 00:32:30 +0100, Jens Kr Kirkebø <jkk@scm.no> wrote:
> Ok, didn't know that. But you still can't run 3-phase motors then, so
> why not 3-phase service. For example, geothermal heat pumps most
> always have 3-phase compressors. Also big pressure-washers, air
> compressors etc.

I run three phase equipment quite often, all I need is a phase
converter to make three phase out of 1 phase.

i

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