BajaNomad

home generator

bajaden - 6-16-2005 at 05:53 PM

Bearing in mind that my electrical expertise consists of plugging something in to a wall socket, does anyone know how to wire a generator as a backup power supply for a house. My wife has ms and doesn't tolerate heat very well, so I have to have some sort of backup. Im open to all suggestions.

Tucker - 6-16-2005 at 06:52 PM

Start at this website for a general idea. You'll need the generator in addition to the auto-transfer device.

http://www.portable-electric-power-generators.com/p_briggs_s...

Bruce R Leech - 6-16-2005 at 07:05 PM

Yes Den I have done it many times

1 you will need a three way disconnect large enough to Handel the amperage of your house.

2 a generator large enough to supply your house.

you can also do the same thing on a smaller scale to back up just the air conditioner and a couple of light bulbs.

remember that if you have an air conditioner that draws 2000 watts that you will need a generator of about 3500 watts output to start it .

I hope this helps

turtleandtoad - 6-16-2005 at 07:20 PM

Depends on how fancy you want to get.

For whole house power:

You can just run both the normal and the e-gen power to a manual transfer switch; in which case you have to start the generator and change over the power yourself;

Or you can go fully automatic with a voltage loss circuit controling an auto-start on your e-gen and an ATS (Auto Transfer Switch) to do the change-over. You can also automate the change back and shut-down.

Or, as Bruce mentioned, you can set up either of the above system to power just certain loads. This requires a few more components (distribution panel, extra transfer switches - manual or ATS), and some existing wiring changes, but you don't need as large a generator.

JZ - 6-16-2005 at 08:03 PM

If you are going to make a statement like that why don't you bother to explain yourself.

turtleandtoad - 6-16-2005 at 08:08 PM

Bruce,
Where am I wrong and why is it bad advice. Everything I said is blessed by the US National Electrical Code (NEC).

Generators

roundtuit - 6-16-2005 at 08:51 PM

There are several ways you can do this, but you must always make such your main power is shut off so you don't back feed to the incoming line or you can fry a lineman. I have a setup where I back feed through my weilder plug to a sub panel. But if you don't know what you are doing sugguest you consult someone with the knowhow :no::no::no:

turtleandtoad - 6-17-2005 at 05:55 AM

That is why you need a transfer switch, either manual or automatic. It will only connect to either the incoming power or the generator. It's physically impossible to back feed when you use one.

They are also called 3-way disconnects, Manual Bus transfers (MBT), or Automatic Bus Transfers (ABT). Although the ABT is actually a brand name, ABT inc.

There are a lot of technical considerations when designing such a system, such as wire size, conductor lengths, load balance, component ampacity, and specific installation procedures. So, for safety, always have a competent electrical type do the design and at least oversee the work.

By the way, backfeeding through a receptacle, such as a welding outlet or dryer plug is illegal in every state in the US and most overseas countries. It's been responsible for numerous deaths (mostly of linemen trying to restore power) and house fires.

Professionally, I have designed over 50 emergency power systems and have had them approved by the regulatory agencies in the US and 7 foreign countries.

turtleandtoad - 6-17-2005 at 09:55 AM

Bruce,
I think you misread me. I didn't state that a manual transfer switch would only work on certain loads. I re-stated what you said, that emergency power can be set up for just certain loads (rather than the whole house) and that this can be done either manually or automatic.

I did state that to isolate and supply just certain loads you have to add some components and do some re-wiring. This is true, you have to move the loads you want to supply to a separate panel and install the transfer switch between this panel and the normal source (or install a second transfer switch). These switches can be either manual or automatic.

This isn't the only way to do it, just the cheapest. You can accomplish the same thing by changing all your circuit breakers to shunt trip types so you can automatically turn off the ones you don't want to be powered by the e-gen. But this is much more complicated and normally much more expensive.

There are other approaches but they don't really apply to home use.

As to the cost; I didn't say it would be cheap to install an automatic system. I just stated that this is an option. For people that have a medical reason for needing a back-up power source, cost may not be a factor.

But actually, with modern technology, it's not as expensive as some would think. For example, you can get a complete 15,000W whole house package from Home Depot for about $3000. This includes the Gen Set, Automatic Transfer Switch, Load Center, 30 ft., 5 ft. & 2 ft. pre-wired conduits, outdoor connection box, flexible fuel line and composite mounting pad and has a 30 HP OHVI Industrial engine which
is either natural gas or LP gas powered and has a pressurized oil system. Everthing is enclosed in an outdoor, soundproof cabinet so noise isn't a problem.(there are also gas and diesel systems available). These are self-contained units with their own cooling system. I've used similar units (only diesel) in the middle of the Saudi deserts and never had a problem

Warm up is not needed and it doesn't require engine pre-heat unless you are living in an area that experiences sub zero temperatures. Then you might need pre-heat but, because of the soundproof enclosure, a 500 watt heater is sufficient. Bajaden didn't mention what geographical area he is in. Since this is the Baja forum, I assumed that he was in Baja, where pre-heat isn't a factor.

The change-over point is adjustable so, if you're in an area that is plagued by brownouts or frequent flickering, you can adjust it anywhere from 30 seconds to 10 minutes.

If you want to buy the stuff individually, you can get an ASCO 200 amp ATS (Series 165) for about 1,000 or the same thing in a 200 amp MTS for about $725. So the difference between automatic and manual is about $275.

Of course you're right about the manual system only taking a minute or two to put online and is probably what I'll be putting in myself. But if power is out for an extended period of time (and I'm not there) I might lose whatever I have in the freezer:O

It's all up to the individual, I'm just pointing out some options.

[Edited on 6-17-2005 by turtleandtoad]

[Edited on 6-17-2005 by turtleandtoad]

Bruce R Leech - 6-17-2005 at 10:01 AM

Quote:
Originally posted by turtleandtoad
That is why you need a transfer switch, either manual or automatic. It will only connect to either the incoming power or the generator. It's physically impossible to back feed when you use one.

They are also called 3-way disconnects, Manual Bus transfers (MBT), or Automatic Bus Transfers (ABT). Although the ABT is actually a brand name, ABT inc.

There are a lot of technical considerations when designing such a system, such as wire size, conductor lengths, load balance, component ampacity, and specific installation procedures. So, for safety, always have a competent electrical type do the design and at least oversee the work.

By the way, backfeeding through a receptacle, such as a welding outlet or dryer plug is illegal in every state in the US and most overseas countries. It's been responsible for numerous deaths (mostly of linemen trying to restore power) and house fires.

Professionally, I have designed over 50 emergency power systems and have had them approved by the regulatory agencies in the US and 7 foreign countries.


this is much better advice this time Mr. toad.

I think the problem here is you are over engineer the system . Bajaden is a good friend of mine and he has a small apartment and is just concerned with keeping the conditioner going in case of a long power failure.

what system to you have on your R.V it is about the same size as his home. do you really need a fully automatic switch over? or can you stand to push the start button on the gen set and while it is worming up go and through the 3 way disconnect.

the 3 way disconnect is easy to install under Mexican code. it can go any where between the regular disconnect at the meter and the distribution Panel [breaker panel]. here they use #8 copper for the service to most houses. so use the same to connect the gen-set and you are in business.
it is nice to live in Mexico.

turtleandtoad - 6-17-2005 at 12:35 PM

Bruce,

I think you're right, I've got to learn how to take that engineer's hat off now that I'm retired. At least in Mexico

Just have someone slap me up side of the head when you see me lapsing into "engineer" mode.

Mike

Bruce R Leech - 6-17-2005 at 12:49 PM

I have the same problem after 35 years of being an engineer. I'm just wish I could spell better. when are you going to be here again?

turtleandtoad - 6-17-2005 at 12:53 PM

I'll be back in January and plan on hanging around until May. Maybe you can point me towards some property while I'm there this time.

Bruce R Leech - 6-17-2005 at 12:58 PM

OK good . BajaDen and his wife Noel are moving down here in July. he is going to tough it out year round with me so I will have some company.

Capt. George - 6-18-2005 at 05:12 PM

Propane Generators????

Enough out there to feed 1600 sq ft house as back up.?

who has best propane generators?

What size would be more then ample?

Want all automatic.....Any info is good info Gracias George

moving further south in October..............

turtleandtoad - 6-18-2005 at 06:42 PM

Yup, propane generators, Just go to the Home Depot website and type in "Emergency Generators" in the search box and you'll see a bunch of "whole house" sets.

The size you need depends on how much power you want, not on sq ft. In the US I'd say check the amprage of your main breaker for a rough estimate of max size but, as Bruce has pointed out, this ain't the US, so the only way I can suggest is to make a list of all the stuff in the house and it's approximate power needs. Then apply a "use factor" (how many hours per 24 hour day that it is in use, 1 being a load running 24 hours, 0.5 being a load running 12 hours, etc; Multiply all loads by their use factor and then add the results up, make sure your working in all amps or all watts) to determine how large a genset you need. If you decide to do it this way, and need help on this let me know.

Otherwise, maybe Bruce or some other "old hand" in Baja knows a better way to estimate your whole house needs based on something in your existing electrical setup.

PacO - 6-18-2005 at 06:54 PM

I've been looking at propane vs. diesel and although the propane has the advantage in wear and maintenence (from my understanding, I've been wrong b4), the diesel fuel seems like it is much easier for the volume I'll end up needing to acquire. The LP generaters are certainly more readily acquired for the dollars. I wonder if you could order one thru Home Depot and pick it up at the one in TJ? That would take care of the aduana issue.

bajaden - 6-18-2005 at 07:24 PM

Wow... I never expected this many responses. I must admit Mr Toad, I had no idea what you were talking about, but I suspect Bruce does. By the way Bruce, Noel tells me her mom worked for an ingineering firm for many years and said they all had one thing in common. None of them could spell. So don't feel bad. There are many people in this world who are great spellers, but are seriously lacking when it comes to communication. Its the content that matters. Thanks to everyone for the information. I did actually assimilate some of it. Im counting on Bruce to help me with the rest.

turtleandtoad - 6-18-2005 at 08:07 PM

Oh, I forgot to mention, if you're trying to calculate the genset size you also have to take into consideration the STARTING current of reactive loads (anything with a motor or transformer) such as refrigerators, pumps, TV's, air conditioners, etc.

Capt. George - 6-19-2005 at 05:32 AM

Muchas Gracias Amigos...again Nomads, a living Almanac...

THere is supposed to be a Home Depot opening in Cabo also..yeehah!

Will figure it out and will certainly call on you T & T if help is needed.

Thanks to all Nomads for being so ready to help!! George

turtleandtoad - 6-19-2005 at 12:11 PM

FYI,
A little online research on LP vs Diesel (for under 100K gensets) appears to give the nod to Diesel, even though the majority of backup gensets in the US are natural or LP gas.

The reasons are as follows,

Diesel
Longer Life
Lower Maintenance
Lower fuel consumption (gal/kw) (although this one appears to be an arguable point)

LP Gas
Clean Burning
Lower initial expense

That "clean burning" is probably why they are so popular in the US.

Of course, it also depends on the local conditions, like what is the price and availability of the two fuels, can you get them delivered, etc.

Bob and Susan - 6-19-2005 at 12:26 PM

I had always thought this way...

1 gal diesel (Mex ~$1.80)
1.2 gal gas (MEX ~$2.30)
1.9 gal propane (MEX ~$3.00)

Big cost differance if you are using the generator all the time.

A barbarque size 5gal propane tank would be used up in a little over two hours
A larger 50 gallon size gone in a 24 hour period

It would depend on the everyday use....

I know my truck is a lot less to operate than a truck thats gas and the same power.

turtleandtoad - 6-19-2005 at 12:39 PM

Propane is that expensive in Mexico?

I though I was paying about 45 cents/gal down there last winter, but maybe I'm wrong.

Bob and Susan - 6-19-2005 at 02:46 PM

WAIT!!!

Maybe I'm wrong....I'm not ALWAYS right....I'll check

PacO - 6-19-2005 at 05:34 PM

I think propane is cheaper...... I've been wrong plenty. However, the convenience of diesel vs. LP seems to be the kicker for me. My place is south of one of the much maligned gringo enclaves and I'd hate to deal w/the hassle of the number of propane tanks I might need. I still need to do a lot of research. I would think a water cooled engine would also be the hot ticket. When it's hot and humid out I wonder if ambient air would cool the engine enough if it's just air cooled. Not that any of this really matters because I'm solid 4 years away from affording this setup.

turtleandtoad - 6-19-2005 at 05:55 PM

I'm not sure about the cooling, the power systems I designed and ran in Saudi Arabia were all water cooled diesel (primarily because the Saudi military had lots of diesel tankers but very few LP tankers) and, on other systems I designed, the clients normally specified their preference for fuel/cooling in advance.

However, they do make water cooled LP units also. Just something to keep in mind when you're ready. It sounds like you'll be ready about the same time as me (if I find a spot I like).

Bob and Susan - 6-19-2005 at 06:04 PM

6 pesos a liter for propane

3.79 liters in a gallon = 23 pesos

10 pesos to the dollar = $2.30 a gallon for propane

About the price of gasoline