Home standby generator

[nhraracer90]

Good Morning,

I am going to be installing a standby generator soon. Probaly 16k Generac. The generator is going to be about 170ft from my house (behind my building & near propane tank). Since it's so far away from the house, I have had different feedback from some people regarding how to hook it up. One electrician said that it would be ok to run wire from the generator to the house and use 100AMP mobile home wire. The other one said that's too far for a generator and said to run the propane line underground up to the house and sit the generator up there. Which option would be best? I have to open up my yard for some other issues soon and wanted to at least get the wire or propane line in the ground.



I would prefer to be able to run just wire to the house, not too crazy about having the propane line around my building and yard.



Thanks

 

[WisJim]

The allowable distance from the house is dependent on the wire size used. Minimum wire size for 67 amps, 170 feet, and 3per cent voltage drop is #4 copper or #2 aluminum

 

[nadogail]

16,000 watts divided by 120 volts comes out to 133.33 Amperes, if my math is correct.

12,000 watts divided by 120 volts comes out to 100 Amperes, using the same math.

Maybe you could reduce your anticipated load and use a smaller unit which would save you fuel and wire costs.

 

[matt_i]

You have to open a trench either way.

It can either contain the propane tube or a set of wires.

You do not prefer the propane tube, so I would recommend to go with conduit and wiring.

Also, a 12kW or 16kW generator is likely generating at 240vac so both bus bars on the interior circuit panel can be fed. Amperage is then cut in half.

 

[u3b3rg33k]

I don't see how it can be "too far" for a generator unless someone doesn't want to do the work. that's a wire sizing/distribution question. how far is the power plant from your house?

 

[firebirdparts]

Good Morning,

The other one said that's too far for a generator

No such thing. There is such a thing as too far for the wire used. Use big enough wire and put it where you want to.

 

[nhraracer90]

I don't see how it can be "too far" for a generator unless someone doesn't want to do the work. that's a wire sizing/distribution question. how far is the power plant from your house?

I will be the one doing the underground work. I will have an electrician do the actual hookups at the house/generator. It will be roughly 170ft from the house

 

[nhraracer90]

No such thing. There is such a thing as too far for the wire used. Use big enough wire and put it where you want to.

What size wire would be best? Something like this?

https://www.lowes.com/pd/Southwire-...rd-Service-Entrance-Cable-By-the-Foot/3129327

 

[nhraracer90]

Also, do I need to run control wires in a seperate conduit as well? To let the generator know when to turn on and off?

 

[infinkc]

Also, do I need to run control wires in a seperate conduit as well? To let the generator know when to turn on and off?

i just picked up a 16kw generac unit. you can run the control wires in the same conduit. If you look at cost, running that much wire at that gauge will cost way more than the pipe for the propane. Propane is already at the house? cant you just run from there?

 

[stonesfan68]

I don't see how it can be "too far" for a generator unless someone doesn't want to do the work. that's a wire sizing/distribution question. how far is the power plant from your house?

Yes, that’s correct. You should find another electrician. I work for a generator rental company and we’ve run correctly sized cables for a mile from the generator to the point of use.

 

[nhraracer90]

i just picked up a 16kw generac unit. you can run the control wires in the same conduit. If you look at cost, running that much wire at that gauge will cost way more than the pipe for the propane. Propane is already at the house? cant you just run from there?

What size control wires should be ran? Is it just 2?

 

[infinkc]

What size control wires should be ran? Is it just 2?

Took this pic for you out of the manual





Sent from my iPhone using Tapatalk Pro

 

[nhraracer90]

Took this pic for you out of the manual





Sent from my iPhone using Tapatalk Pro

Thank you for this. Do I need 6 control wires? I was told just 2

I'm assuming a standard stranded wire?

 

[Stuart in MN]

Typically, there's a start signal sent from the transfer switch to the generator, and then the generator has a running signal and an alarm signal that are sent back to the transfer switch. The signals may share a common ground wire, but the manual should have information on exactly how many control wires are needed for your specific model. You should be able to download a copy of the manual from the manufacturer's website.

 

[yeldogt]

Generac sells a bundled cable w/ controls wires -- they do it so you only need one conduit. It's not code in my area ... so no go for me. It also allowed for minamal control .. it was on and off

If you have to have it inspected and they follow the new code you have to do a load on the property - make sure the generator can handle the load if using an automatic switch.

It's nice to have the generator away from the house .... but this does depend on the model and how often you will need it. The newer units are much quieter ... but if you lose power for days at a time -- not sure I want it outside of my bedroom.

I ran a 2" conduit to my 20/22kw Cummins unit ... the low volt was in another 1" . I ran another 1" for some lights. I'm around 100' away .... I put the unit 10' feet from the tank.

My unit needed more low volt wires for the optional inside control -- That allows me to see what it's doing and control it from inside. Also -- I need load shedding for code .. more low volt wires.

If you have to have it inspected ...make sure you understand it all before you buy

 

[firebirdparts]

What size wire would be best? Something like this?

https://www.lowes.com/pd/Southwire-...rd-Service-Entrance-Cable-By-the-Foot/3129327

Wisjim in the 2nd post. #2 aluminum or #4 copper. In real life that would be gracious plenty because you can't really keep the generator perfectly maxed out right at 16kw.

That 4 aught stuff is more than you need. That's enough for a 200 amp service.

That is still not going to be cheap, of course.

 

[larry4406]

The Generac manual says that for propane you need 1.25" propane line for 16kw (540' max) and 1.25" 480' max for 20/22 kw.

 

[dcg9381]

16,000 watts divided by 120 volts comes out to 133.33 Amperes, if my math is correct..

I think these are wound 240v.. Someone correct me if I'm wrong. So you're looking about 1/2 of the above for capacity. IE - under 100 amps.

Standard voltage drop calculations would apply.

We're doing one of these too, in the 20KW range. It's likely cheaper for us to run propane than it is to run wire per foot...

 

[infinkc]

Thank you for this. Do I need 6 control wires? I was told just 2

I'm assuming a standard stranded wire?

havent installed mine yet, but i am pretty sure it is 6 wires.

 

[Jackfre]

I would run the gas line and locate the unit closer to the house keeping in mind that they are not quiet units. Not sure on this but I bet the poly gas piping will be cheaper to run than the necessary wire. Being in the CA foothills and the fires all ready going off our local fire code required a clearly labeled "Emergency Generator Shutdown" disconnect within three ft of the transfer switch for protection of the firemen. Not a bad idea in any case, especially if you are that far away and something goes sideways.

 

[PCMusicGuy]

I would also run the gas line in the trench and put the generator closer to the house. The newer Generac units are pretty quiet compared to the stuff from 20-30 years ago.

 

[Bigbandguy]

One thing to look for with a Generac. Unless they have changed the location for the battery charger the charger is located at the panel and there is a line to the battery located at the generator. The line to the battery is pretty small and if it is too long there is insufficient current to charge the battery. I know of a setup that kept burning out batteries and it turned out that the charging line was too mall. Replacing it with #14 Romex solved the problem. That was a pretty klunky fix but it worked. If your control run is going to be really long you need to be aware of where the charger is located and may need a float charger at the generator with a way to power same.

 

[Fasthotrod]

If I were you, I'd look at what is most important to you. Generator location? Cost? Then decide from there.

I just had an 1.25" poly gas line installed between my house and my shop. They came out and dug the trench, set the line, installed risers on each end, pressure tested everything, made the connection at the meter, and back filled the trench. $975 all in. They came out with a 100 ft. roll, used about 85 feet of it.

If I had rented a trencher for the day ($200) and bought the materials myself, I could have done it for a bit less... but I really didn't care to mess with it.

 

[Fasthotrod]

One thing to look for with a Generac. Unless they have changed the location for the battery charger the charger is located at the panel and there is a line to the battery located at the generator. The line to the battery is pretty small and if it is too long there is insufficient current to charge the battery. I know of a setup that kept burning out batteries and it turned out that the charging line was too mall. Replacing it with #14 Romex solved the problem. That was a pretty klunky fix but it worked. If your control run is going to be really long you need to be aware of where the charger is located and may need a float charger at the generator with a way to power same.

Good info right here... best to check that out as well.

The Kohler 20kW that I installed at my in-laws has the battery charger located inside the generator enclosure, which requires a 120 VAC circuit. (There is also a provision for a carburetor heater for cold weather applications, that also requires 120 VAC.)

The Kohler industrial units we had (until recently) had a wall mounted battery charger that required four wires between the battery and the charger. Two were heavier gauge for the charging circuit, and the other were smaller gauge sensing leads to help the charger account for the voltage drop between the charger and battery. Newer industrial units are coming to us with the charger installed on the generator.