home emergency power

[kcaj]

I would like to install an emergency generator for my house that would supply the equivalent of my incoming service which is 150-amperes, 120/240-volts.
Is this feasible and what size (kW) generator would I need? Is (150 X 120)/1000 = 18 kW correct?

 

[bphgravity]

The generator would need to be sized to carry the calculated load as determined by Article 220 of the NEC. Your loking at more like 35 kW for 150 amperes.

 

[petersonra]

I would like to install an emergency generator for my house that would supply the equivalent of my incoming service which is 150-amperes, 120/240-volts.
Is this feasible and what size (kW) generator would I need? Is (150 X 120)/1000 = 18 kW correct?

really it would be 240V X 150A = 36KVA. we can call it 36 kW.

But do you ever really use all that power?

It is usually more cost effective to decide what loads are really important to you when the utility power is off and only supply those loads through your transfer switch. Someone familiar with these types of installs can give you a better idea how big of a unit you really need.

Hopefully when you used the phrase "I would like to install" you really meant you plan to hire someone competent to do it. You will need an electrician to do the electrical part and probably a plumber to do the gas hookup, preferably people with some experience in these type of installs.

 

[77401]

You can probably get by with a 10kw or smaller generator.
get one with an automatic transfer switch. Lowes & depot have then for a decent price online.
You only need(must have) circuits, for your central A/C Look @ the name plate. Furnace/blower, refrig, microwave to cook with, alarm, a small tv for news & updates.
Any thing else is not truely necessary.

 

[MasterMike]

Generator Calc

Generator Calc

The Generators I install are based on the swuare footage (Rule of Thumb) and the AC. The rule of thumb for the AC is 4Kw per ton of AC. The remaing well thats up to you and how you want to operate.

4 Ton AC = 16 Kw This is for the starting capacity
3000 square feet x 3 va per foot = 9 Kva

The answer if you have a 3000 square foot house is 25 Kw

 

[77401]

Master Mike
What typically do you charge for the Install without the generator?

 

[ty]

Master Mike
What typically do you charge for the Install without the generator?

While I can't speak for Mike,
We will not do the install without supplying the generator.
We are certified to install the generators that we supply, as well as certified to maintain, troubleshoot, and repair them.

When paying the cost of these systems, the customer should get the reliability that they expect.

 

[sceepe]

Just a thought. You really don't want to oversize the generator if your generator is for post storm use. Other than obvious cost issues, the bigger the beast the more it eats. If you are running from on site tanks (LP or Diesel) your are gonna run out of go juice too soon. And you are back to cooking over the camp fire. If your running on natural gas your assuming that the distribution station up the line has power to keep you in the gas.

 

[bphgravity]

This is the guideline we give out to contractors in my jurisdiction:

When installing generators to be connected to household electrical service, obtain proper Building Department permits and hire professionals
State officials are encouraging Floridians to depend more on their own resources should a hurricane strike. Hearing that message, many have begun purchasing generators and transfer switches that allow those generators to be connected directly to the household electrical service panel.

If you are planning on having such a system installed, you must first apply for a permit from the North Port Building Department, and the work must be inspected by the City upon completion.

Because installing a generator is very complicated, the Building Department strongly recommends that a licensed and insured electrical contractor and qualified generator installer be hired to do the job.

If you are planning on installing a generator to be connected directly to your home?s electrical service, refer your installer and/or electrical contractor to the following North Port Building Department guidelines.

Please don?t hesitate to contact the Building Department at 423-3186 if you have any questions.

Application Permit Requirements
A standard City of North Port permit application for installing a generator connected to a home?s electrical service costs $40.00, plus any applicable surcharges. Documents required at time of application include:
1. A site plan showing the generator?s location;
2. The location of the generator?s fuel source and the type of fuel to be used;
3. Manufacturer?s specifications;
4. An itemized list of the electrical loads to be served, including any motor loads using motor startup current;
5. Diagrams of feeders, including the size and type of conductors to be used.

Contact Florida Power and Light before installation
If it is necessary for the electrical service to be turned off, or if access is required inside the meter enclosure, the homeowner or installer must contact to arrange for disconnection of the electrical service. The toll-free telephone number for FPL is 1-800-226-3545.

After the installation
After installation, contact the North Port Building Department at 423-3186 for the required final inspection of the work. PLEASE NOTE that the City must approve the work before FPL will restore power to the premises.

Guidelines for Portable Generators with Manual Transfer Equipment:
Permanently installed equipment for the connection of a portable generator must comply with Section 702.6 of the 2002 National Electrical Code (NEC). The manual transfer equipment will require an interlock device suitable for the intended use. This device must be installed to prevent the inadvertent interconnection of the normal and the optional system supply. The connection device must be a UL Standard 231 Listed Power Outlet. The back-feeding of electrical outlets within the home is not permitted.

Guidelines for Permanent Generators with Manual Transfer Switches:
Permanently installed generators with permanently installed manual transfer equipment must comply with the provisions for portable generators or use a Listed Transfer Switch or Panel Board. The equipment must be installed so as to allow the user to select the connected loads upon manual transfer.

Guidelines for Permanent Generators with Automatic Transfer Equipment:
Permanently installed generators with automatic transfer equipment must comply with the provisions of Section 702.5 of the 2002 National Electrical Code. The calculated load as determined by Article 220 of the 2002 NEC must not exceed the rating of the generator output. Please note that a ?Demand Load? will not be accepted in lieu of the calculated load.

ALL load calculations must be included with the approved permit documents and must be available on site with the permit placard at the time of the inspection. All transfer equipment must be listed. Automatic transfer equipment installed on the supply side of the method of disconnecting the service must be listed as suitable for use as service equipment.

Required permanent signs for all installations
Permanent signs must be posted at all of the above-described installations that comply with Section 702.8 of the 2002 National Electrical Code. The required signs must indicate the type and location of the on-site optional standby power source, and must be permanently installed and located at the service disconnection point and at the meter enclosure.

All equipment must be installed according to the manufacturer?s instructions.

Portable generators with built-in power receptacles
Generators that supply power to connected equipment through built-in receptacles mounted on the generator DO NOT REQUIRE PERMITS OR INSPECTIONS.

However, they must be placed well away from a home or any air intake to prevent the danger of carbon monoxide poisoning.

As with any of the equipment listed above, be sure to read and follow all safety precautions in your user?s manual.

 

[dlhoule]

You can probably get by with a 10kw or smaller generator.
get one with an automatic transfer switch. Lowes & depot have then for a decent price online.
You only need(must have) circuits, for your central A/C Look @ the name plate. Furnace/blower, refrig, microwave to cook with, alarm, a small tv for news & updates.
Any thing else is not truely necessary.

Just why would anyone want to spend the extra money for the central A/C for something they will probably only use for 5 or 6 days every 5 or 6 years? I've had my generator for 7 years and it has less than 48 hours of run time on it; part of which has been only for periodic testing.

 

[MasterMike]

Master Mike
What typically do you charge for the Install without the generator?

It all depends on the generator size, sevice, and the transfer switch. Labor is diferent for each one also.

 

[MasterMike]

Just why would anyone want to spend the extra money for the central A/C for something they will probably only use for 5 or 6 days every 5 or 6 years? I've had my generator for 7 years and it has less than 48 hours of run time on it; part of which has been only for periodic testing.

Your not from the Gulf Coast I can tell that, ask the people in New Orleans, they still don't have power since last years storm.

 

[ramdiesel3500]

kcaj
This is a little late, but just for comparison sake, I have a 200A 120/240V service at my home. I am total electric except for my aux. wood burning furnace. I live in a very remote area that has frequent outages. I recently relocated my service from my house to my barn. I now feed the house as an out building. When I moved the service, I installed a 200A transfer switch so that I can transfer my entire load to generator power when needed. I use a little 5KW portable generator that has a 10hp gasoline air-cooled engine. (paid $649.00 for it 8 years ago, can buy it now for $549.00). When utility power fails, I first walk to my loadcenter and turn off all 2-pole branch breakers (hot-tub, dryer, water heater, oven, both A/C units). Then I turn off all 1-pole breakers that feed motorized loads (refrigerator, freezer, water pump, septic pump). Next, I fire up the generator, plug it in, and throw the transfer switch to "gen". After a couple of minutes letting the generator warm up by powering lights and TV (kids you know) then I turn on, one at a time, the 1-pole motor loads.
I cannot run my dryer (5500watts) or hot tub (17,000watts) with this unit. But I can select the other 2-pole breaker loads, one at a time only, as needed. We actually get by quite well this way. We have had one 4-day outage in the hot summer time and one 4-day outage in the dead of winter. The outdoor wood furnace makes heat and hot water with fractional hp motors. The winter outage was easy. Only inconvenices were fueling/maintaining the generator and we had to make a couple of trips to the laundromat to dry clothes. The summer outage was a little uncomfortable as I could only run our smallest A/C unit part of the time.
Sorry for the long post, but I thought you might like to hear the experiences of a long-time generator user. I am convinced that a small generator can usually supply 90-95% of the needs of the average household. I am able to run about 18-20 hours on a 5 gallon tank of fuel. Largers generators will burn much more without any additional load unless you go diesel!
Hope you find this helpful!

 

[dlhoule]

Your not from the Gulf Coast I can tell that, ask the people in New Orleans, they still don't have power since last years storm.

Gee, how intuitive. I just don't understand why anybody wants to live under such conditions. Heat, hurricanes, tornados, severe thunderstorms, flooding.

Does it have anything to do with being stupid? No, I don't think so. I suspect it has something to do with not liking the blizzards, bitter cold, tornados, severe thunder storms and so forth that we get to have.

We do at least have changes of Season.

 

[ramdiesel3500]

Larry
I have told my wife many times that if we ever leave Indiana, I want to move to the land where snow blowers have turbochargers!!!!
I think Michigan would work just fine!!!

 

[frenchelectrican]

I want to move to the land where snow blowers have turbochargers!!!!

LOL yeah yeah turbodiesel snowblower that will raise everyone eyebrows to see what the heck is that

i did irraited my neghbor few time he have turbodiesel truck well ,, that was not bad but just try to listen to Hatz diesel engine rev up while mowing grass that get their attetion


Merci , Marc

P.S. just try to listen to the olde detorit diesel duex [ 2 ] stroke with V-12 engine that will scream pretty good

 

[MasterMike]

Gee, how intuitive. I just don't understand why anybody wants to live under such conditions. Heat, hurricanes, tornados, severe thunderstorms, flooding.

Does it have anything to do with being stupid? No, I don't think so. I suspect it has something to do with not liking the blizzards, bitter cold, tornados, severe thunder storms and so forth that we get to have.

We do at least have changes of Season.

We to have season changes but not as ~~Drastic~~ as shovel 36" of snow from our drive ways, which since the storm are partially in tacked. We enjoy the hurricane parties while enjoying the nice 80 mile an hour breeze before the storm.
We also like the warm weather where we don't have to cut holes in ice to fish. LOL

 

[roger]

Another problem with oversizing is, if a diesel generator is involved wet stacking will occur unless you deliberately load it to at least 30% it's capacity for an extended period of time. This will also take monitoring/testing the fuel if left in the tank for an extended period of time.

It is generally better to size the generator smaller than the service, and in reality, if you were to access your POCO records, you would probably see your average less than 30-40 amps, and peaks no more than 60-80 amps at most times.

To properly size a generator, motor starting loads, fuel type, altitude, UPS's and other factors come to play, it is more involved than basic ohms law.

Although, if the biggest is for bragging rights, go with something like a 1125 kw and have the whole community connect to it.

Roger