Prewiring for generator - new house construction (alternatives, AC, installation)

[bghouston]

Returning back to the forum which has given me invaluable advice in the past few months.

Friends - We are in the process of finalizing the electrical plan for the new house build and I asked the design team to include provision to wire in a future generator. This is the response I get from them -

"we need the exact specifications/model number of the generator that you plan on having at your home. This is not a universal item that we can “pre wire” for. Each generator has certain specifications."


What are the latest future proof alternatives out there now and what kind of generators should I be researching out ? Not planning to buy any now at all as we have blown the upgrade budget and its really not necessary at this time. However, want to ensure that if I do buy one in the future, my electrical layout is ready to be connected with the generator.

I am not sure how this whole generator concept works and if it will help me power a whole house when needed. (2 storey, 4000 sq ft). Just need to understand how I should approach this at the initial design phase, so any guidance will be really helpful.

Thanks for your time !

[DSL_PWR]

Call Generators of Houston and talk to them about what you need. I would get a Kohler. They run better and smoother especially for sensitive electrical components in your home.

The transfer switch it really what counts. The gas tap needs to be close as well if you want it to run off NG.

I'd look at getting at least a 20Kw generator.

[PedroMartinez]

Two places I would look when shopping:

Natural Gas Generators for Home Power or Prime Power

Generac & Briggs Standby Generators - Backup Generators | Wise Sales

[bghouston]

Originally Posted by DSL_PWR

Call Generators of Houston and talk to them about what you need. I would get a Kohler. They run better and smoother especially for sensitive electrical components in your home.

The transfer switch it really what counts. The gas tap needs to be close as well if you want it to run off NG.

I'd look at getting at least a 20Kw generator.

Thank you !

Where would the transfer switch be placed and where do you need to factor for a gas connection - will that be garage and is that the typical place for generators ?

[marksmu]

I just finished my new house and was in the exact same situation as you are in now. I wanted to prewire for a whole home generator, but I could not afford the generator and the install of the generator right then.

There are two options when it comes to generator pre-wiring.

Option 1 - essential circuits. In this option you say that you want only the kitchen and your master bedroom and their AC units on the circuit...everything else is "non-essential" and therefore not needed. This is the cheaper option b/c you end up with a smaller transfer switch and a smaller generator. They will then run a load calculation for those circuits, tell you that you will need say a 100Amp transfer switch and a 18KW generator, and you know what you need. Just get the correct transfer switch at that time.

Option 2 - Whole House - You put a transfer switch that will enable you to power your whole house in now. Most electricians want to sell you the switch, generator, and install for all of them. The margin on the generators is pretty high, so they don't like to install just the switch....They tried to tell us you need to match the generator to the switch to the demand, etc, but its not true. A generator puts out a set current and a set Amperage...so long as your panel can handle the load of your house, you can buy any size generator....A generator that is too small will overload and trip the breakers and can result in damage to the generator. It can not hurt the house. A generator that is too large, will just run at a lower speed and may be outside of its peak efficiency curve...It also will not hurt the house.

I have a fairly large house, and I ended up with two 150Amp automatic transfer switches that I will have to manually turn on when the power is out. I have a small 13KW portable generator and stubbed an umbilical cord to it. I cant run my whole house by any means with it, but I can manually turn off the breakers I don't need and still be able to have the option to choose what I want to run rather than being limited by having hard wired to only essential circuits.

FYI, there is a huge difference in price between air cooled generators and water cooled generators....you can get Air cooled upto something like 18 or 20KW and then you need to goto liquid, which is a huge price jump.

Hopefully that makes sense...It took quite a while to convince my builders electricians to do what I wanted b/c they only wanted to sell me a whole package setup and I could not afford the generator.

Originally Posted by bghouston

Returning back to the forum which has given me invaluable advice in the past few months.

Friends - We are in the process of finalizing the electrical plan for the new house build and I asked the design team to include provision to wire in a future generator. This is the response I get from them -

"we need the exact specifications/model number of the generator that you plan on having at your home. This is not a universal item that we can “pre wire” for. Each generator has certain specifications."


What are the latest future proof alternatives out there now and what kind of generators should I be researching out ? Not planning to buy any now at all as we have blown the upgrade budget and its really not necessary at this time. However, want to ensure that if I do buy one in the future, my electrical layout is ready to be connected with the generator.

I am not sure how this whole generator concept works and if it will help me power a whole house when needed. (2 storey, 4000 sq ft). Just need to understand how I should approach this at the initial design phase, so any guidance will be really helpful.

Thanks for your time !

[PedroMartinez]

Originally Posted by bghouston

Thank you !

Where would the transfer switch be placed and where do you need to factor for a gas connection - will that be garage and is that the typical place for generators ?

Typically, you want the generator and the transfer switch located where your gas main and breaker box are located. The power and gas tend to come in at the same location.

You would not put a generator, in most cases, in the garage due to the fumes and heat.

Have the builder tell the gas company to put in the high pressure meter so that you won't have to have that swapped out later. The standard meter (I believe) allows half a pound of pressure to come through while the larger meter allows three pounds of pressure. Regulators down line reduce the pressure.

[marksmu]

I believe Centerpoint now requires a second meter for generator installations. You are correct that you need a much bigger meter though.

Definitely do not put your generator in the garage...its not even legal to do, but even if you got a portable one, its very bad. If possible put it as far from the house as you can, then run power to the house underground. Generators make a decent racket unless you pony up for the very expensive quiet ones.

Originally Posted by PedroMartinez

Typically, you want the generator and the transfer switch located where your gas main and breaker box are located. The power and gas tend to come in at the same location.

You would not put a generator, in most cases, in the garage due to the fumes and heat.

Have the builder tell the gas company to put in the high pressure meter so that you won't have to have that swapped out later. The standard meter (I believe) allows half a pound of pressure to come through while the larger meter allows three pounds of pressure. Regulators down line reduce the pressure.

[ethanw]

Get you a 20K universal transfer switch and make sure you have an approved and right size natural gas line to the generator location. A concrete base for the generator will help as well Then later you can add whatever generator you want. This is what I did.

[astrohip]

Originally Posted by PedroMartinez

You would not put a generator, in most cases, in the garage due to the fumes and heat.

You can put a generator in a garage if you want to be on the news.

Originally Posted by marksmu

I believe Centerpoint now requires a second meter for generator installations. You are correct that you need a much bigger meter though.

Was not aware of this. Do you know why?

Originally Posted by ethanw

Get you a 20K universal transfer switch and make sure you have an approved and right size natural gas line to the generator location. A concrete base for the generator will help as well Then later you can add whatever generator you want. This is what I did.

Pretty much this.

Elec meter and Nat gas tend to be right next to each other. Do what ethanw says, and everything will be ready to place a generator at a later date.

You want a whole house generator. Don't try to put some circuits on it. Just do the entire house. If you can afford 4,000 sqft, you can handle a generator sized to power it.

[PedroMartinez]

Originally Posted by ethanw

Get you a 20K universal transfer switch and make sure you have an approved and right size natural gas line to the generator location. A concrete base for the generator will help as well Then later you can add whatever generator you want. This is what I did.

FYI, some generators have transfer switches designed specifically for their units. Generac is one such instance. This does NOT mean that you can't connect any generator to a "generic" transfer switch, because you can, it might be easier and cheaper (in terms of labor) with a "plug and play" transfer switch and generator in such cases.

But Ethanw is correct, a universal transfer switch will work on any generator as long as the loads are appropriate.