Steps for installing a transfer switch

Some of them make sense in one case out of a thousand and make zero sense except in such special circumstances -- but many practicioners don't have (or need) the training (or time) to recognize these special circumstances. Hence codes -- ya don't have to understand it, ya just have to do it.

it's perfect for him.

Just what formula do you use to conclude that a particular generator is "undersized".

Let me give you some examples of load in my house

- 220v kitchen range/stove, 50A breaker, probably 40A use under certain conditions

- 28A central air conditioner

- 15A window A/C (115V)

- Various motors, I would say 10a max at 220v. (refrigerators, gas water heater, freezer, sump pump)

- Lighting, a lot of compact fluorescent, but not all, could go up to

2 kW (say 10A 220v)

- Spa heater, 15a 115v

- computers and TVs, 1 kW

That adds up, unless I am mistaken, to roughly 23 kW. That would be almost "worst case" electricity use, not counting my welder and compressor or other possible loads.

Would you say that a generator below 23 kW is "undersized" for my house?

Or would you use some common sense and recognize that electricity usage could be reduced by taking just a few steps, such as turning off the A/C units, not using the kitchen range and turning off the pool heater.

If the latter is the case and you recognize the fallacy of wanting to power everything at once, then look at my power usage under the following conditions:

1) No A/C use 2) No kitchen range use 3) no hot tub heater use 4) Use of half of other loads (fewer TVs, computers etc) 5) not all motors running always at once

I hopet hat you agree that the above is quite reasonable for emergency situations.

Then energy use comes to, if I did not make a mistake, 3-4 kW.

My generator is honest 7 kW. That means that it can produce 7 kW continuously, stopping for oil changes and other maintenance only, as a prime power unit. It is not some Home Depot "7kW peak load" POS.

That leaves plenty of extra power from my 7 kW generator. Enough to probably run one small burner on the kitchen range, or a window A/C (this one is more questionable), a lot of light, furnace and water heater, computers, TVs, tools etc.

So. Can you explain why you called my generator "undersized".

Thanks.

i

If one of the higher hp motors comes on line with a good load already on the generator, it will puke.

John

The highest HP motor in my house is the sump pump motor, 1/2 HP, and it is one of the harder starting ones if there is water in the sump pump's pipe.

If the rest of the loads use up, say, 4 kw, and the pump requires 4 times its rated power to start up, that adds up to 4000+350*4 = 5,400 watts, not a big deal.

If we deal with numbers, it becomes relatively apparent that 7 kW is plenty for a house that is not trying to produce a christmas light extravaganza and uses NG for heating.

As I said, I already did run the house on this generator.

i

the main breaker most of the time needs wired in...not snaped in... Better shut off the power...

Y'know, I recall a post someplace (I'll be dipped if I can recall where) about doing the "100% manual, total-switchover" thing. Let's see if memory serves me -

Wire generator to appropriate-sized box containing proper amperage power socket.

Wire meter side to an identical-but-separate box/socket nearby.

Wire house side to appropriate-sized box with a pigtail ending in a single plug that matches the two sockets, placed so that the plug can easily be plugged into either socket.

Grid operation: The house pigtail is plugged into the meter socket.

Generator operation: The house pigtail is pulled out of the meter socket and plugged into the generator socket.

Seems to me that would constitute absolutely failsafe generator isolation/switching for "Real Cheap", and should still be kosher to inspectors, assuming proper wire sizes/sockets/plug/etc. go into the work.

I also remember reading about a neighborhood "emergency power co-op" that had many of the houses set up in a simliar way, with the special purpose of keeping things cold/warm. A special FFF - "Fridge, Freezer & Furnace" circuit ran out to a setup as described. Normal operation had that circuit plugged into a dedicated box off the breaker panel. During an extended outage, a shared generator with a custom pigtail to a socket matching the house plugs made the rounds - A couple hours at each place kept everything frozen proper and/or warmed up the house.

EEP!!!!

RUN AWAY!

You're setting yourself up for a complete disaster if you try that action! You *DON'T* want to be dinking around running extension cords to neighbors when you're running off a genny - The losses in the cords will eat you (and your generator - and if things go completely wrong, one or more houses...) alive unless you're in a rowhouse/apartment building type situation. (and even then, you're dicey)

I misunderstood (or more likely didn't read close enough) previous posts.

Steve

There's another issue (in agreement with Iggy) that hasn't been mentioned, fuel consumption. An "oversized" generator will consume more fuel at the same load than one sized correctly to the load. Generators aren't cheap to run.

Steve

Ignoramus16089 wrote:

So hook it up and go, or fairly pay a competent electrician for his value added by helping you. You've noted eariler that you are well-compensated on your day job, better than most by implication.. Given that, I find your continued persuit of free advice (and rejection of most) a bit distasteful.

I think you could be a net contributor here. I also think that you regard yourself as "an operator", smarter than the likes of we and cleverly sucking all that can be had from the public tit. Your proudly-declared recognition as a troll supports that opinion.

Yes.

According to my very approximate calculations, I store fuel for approximately a week of running my generator nonstop, and a month of running it only sparingly (with about enough time to keep the house warm in winter).

With a larger generator, I would need a lot more fuel to be stored, which would become a practical issue. I think that while 7 kW is adequate, the perfect generator size for my house would be 10 kW (which would let me run central A/C in summer), but, that Onan DJE was available at the right price ($600) and other gensets were not available at the right price. I gotta work with what I have.

i

Don, yes, I want to do it by myself, but I want to do it right as well. It needs to be approved by our village inspector. Hence my questions.

i

how many gallons do you store? Any issues with the containers being subjected to heat or fuel dilution (you use Sta-Bil?)?

actually, the solution to central A/C is very simple. we live in a hurricane area and use 2-compressor,2-stage heat pump systems. during a non-power event the system runs exclusively on the smaller compressor which consumes just 1200 watts of power and while not able to cool house to 72F it is able to maintain 78F on a 92F outside temp day.

On Mon, 21 Aug 2006 02:32:55 GMT, with neither quill nor qualm, Ignoramus16089 quickly quoth:

Why not? This sounds like there might be a story behind it. Anyone got horror stories of auto-transfer switching boxes?

Nice thought, bad idea. You'll have no control over what they end up plugging into their connection to your genset, plus all other neighbors for blocks around will want to connect, too. But, it's your call.

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On Mon, 21 Aug 2006 03:04:17 -0700, with neither quill nor qualm, Don Bruder quickly quoth:

Wouldn't 400 amp wire be a bit rugged to move around? Let's see, 4/0 wiring can handle 265 Amps. Does NEMA make 400A connectors? I'll bet both of THOSE items are cheap.

Ig said:

I had forgotten about the lawsuit factor. They'll sue if your genset stops and their fully-stocked freezers full of food rot, if they or their kids trip over the cord and break a wrist/leg/skull, or when the parrot chews through the extension cord and fries itself while starting the house on fire. But it's Ig's call.

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Idunno... I've encountered welding cables that were flexible enough to be used for this purpose. Can't say for sure what the gauge on 'em was - AT LEAST 2/0, maybe bigger. You are aware that you can parallel conductors to increase load capability, right?

Beats me! I ain't ever haddashop fer one.

OK, *RELATIVELY* cheap :)

The plot may have been for just a limited sub-set of circuits to be powered by the genny, rather than the whole house. As I said, I was/am work> >> Exactly my plan. Plus I am planning on sharing this with my neighbors,

Yeah, I'd forgotten the lawsuit potential, myself. I was thinking purely in terms of cooking off wires due to the long-distance drop inherent in such a scheme.

When that is the case, I agree. Shut the main off, pull the meter.

8 jerry cans, each is 5 gallons. The jerry cans are in plastic storage bins, to prevent contamination if these cans leak. I have not yet put any sta-bil in them, but I will do that shortly. The stuff that I will use is not called sta-bil, it is some other compound that is well regarded for diesel fuel, its name escapes me at the moment. Heat is not a big issue, as these cans are stored in the bushes with plenty of shadow.

That's very nice, I asked our HVAC guy about doing same, but we cannot do that with existing furnace and replacing a furnace seems not to be worthwhile.

i

I can try to look up if you are interested. I remember reading some. I just do not like the idea of engines starting in my yard unattended.

I have a panel from a UPS with pop-up circuit breakers. I want to put it in a box to address just this issue. Even as little as 500 watt, with some overload capability, would do a lot to keep a house warm and slightly lit.

i