Jump to content

What type of generator to buy........


Recommended Posts

stevensanph

I've been looking at generators for ages.  My concerns have always been that I have no idea what size to get.  My house usually runs about 400kwh a month - I have never seen the meter over about 1.5kwh, even with the aircon running (a 0.45 horsepower window unit rated at 550w!), so I figured a 3000w generator would power the whole house?

 

Am I right in my assumption (based on Tinbum's calculation above I am)?  Can I wire it direct into the main circuit breaker or do I need to do something else between the two?  If its rated to 3000w, will I actually get that, or is it like running a car engine at max revs for hours on end?!

Link to post
Share on other sites
  • Replies 93
  • Created
  • Last Reply

Top Posters In This Topic

  • Mandingo

    12

  • thebob

    10

  • Paul

    10

  • stevensanph

    7

Top Posters In This Topic

Popular Posts

I might as well add my 2 cents worth, since I have been running everything off my generator since Nov. 8 when the power went off.   I have a 5kw, Kubota, diesel generator rated at 100% duty cycle.

Guys, PLEASE, if you know little to nothing about electricity, again, PLEASE, let a proper electrician connect a generator you may buy, to your home circuits. Back feeding into the electric grid can b

If you can find one at the moment .......................   In Bohol you wouldn't be able to buy one anywhere .... they're all sold out. A friend of mine here sourced one in Cebu, 8.5kw for 68k peso

Posted Images

  Can I wire it direct into the main circuit breaker or do I need to do something else between the two? 

...... petrol genny wired into the house on the south side of the main circuit breaker. With the breaker in the off position we ran all the lights needed........

 

Just make sure the genny is wired into the load side of the circuit breaker, NOT the feed side. Also very importantly, make sure that the circuit breaker is in the OFF position otherwise all sorts of nasties will happen. As i wrote above, i have left the short tails permanently in the circuit breaker to facilitate quick connection in the future. Just make sure that the ends are securely isiolated as when the circuit breaker is live, so are the ends of your tails!!!!! 

Link to post
Share on other sites

I would also wire the genset after, (south off), the main beaker, via a "on-off-on" type switch.

 

it must have a "center off" position, so only 1 input can enter your home, at any time.

 

Heaven forbid the local mains and genset touched each other!... beware!

 

15A breaker for a 3kva genset going to the switch, and a

10A breaker for a 2.2kva, and

6A for 1.5wva should do the trick. :good:

 

Better safe than sorry...

Link to post
Share on other sites

So what are cheapest in fuel, to run...a 8kw with nearly full load, 15kw with 50% or 30kw with 25%?

Link to post
Share on other sites

Ha!!! Funny you should ask this.

In my experience.

Genny's run at a constant speed regardless of load. My genny used the same fuel with all the lights off, fridge off etc as having all lights on...... To date i have not come across a genny that is speed /load coupled. However there are those that have a kick in system where no electrical load gives a high idle setting but the moment a load is detected, the genny kicks in to full running mode.

Therefore, taking this into account and your question above, the 8KW with nearly full load will be the most economical with the 30kw at 25% load the thirstiest! But then again you will have to study each genny's fuel consumption, normally aspirated versus forced induction, age and condition of the set..........

 

Detour's reply is a very proper and safe way of doing what i did.Follow this example and not really mine, i'm a bit animalistic!!!

Edited by Tinbum
  • Like 2
Link to post
Share on other sites
stevensanph

ok, another stupid question.  If you are powering the gen into the load side, what happens when the feed side becomes live again?  Surely then you have both the mains and gen powering the same circuit?  Or does the On-off-on switch go into the mains line, with one side having mains - on - feedside and the other side having gen - on - loadside?

 

The reason I ask (and yes, I realise to many these will be stupid questions! - sorry) is i've had the conversation with our local electrician and he didn't seem to have a clue what to do...

Link to post
Share on other sites

The transfer switch secure only main or gen, is connected

 

 

MTSBasement1209.jpg

  • Like 1
Link to post
Share on other sites
stevensanph

ok, so the transfer switch is the 'on-off-on' switch mentioned earlier? The 'load center' is the main circuit breaker? If so i've got it now :)

  • Like 1
Link to post
Share on other sites
stevensanph

what brands to people recommended?  I've seen the ones in Wilcon and Ace - are these reliable are am I better looking for a more reliable brand?

Link to post
Share on other sites
SkyMan

I'm going to tell you what I did and there are probably some here that will tell you I'm insane but it worked well for me.

 

Remember that my gen is small 1100W.  Maybe it peaks higher but for normal operation, 1100W.  I have no AC and didn't use anything that would peak or draw large current like microwave, coffee maker, CRT TV etc. just our small ref.  We don't have a breaker panel like a regular house.  We have a 30amp breaker in a lock box on the pole.  From there the power runs underground to our house which has its own 30amp breaker and to the caretaker house/garage also with a 30amp breaker.  I turned all breakers off.

 

The gen came with a special round 3 prong plug.  After pondering this a while I took an 8 ga. stranded extension I'd made and removed the female end and connected the 2 wires to the 2 copper prongs on the round plug and left the ground prong, silver, alone.  I now had a male round gen plug to male typical 2 pronged plug.  I put the gen in the garage and connected the round plug and fired up the gen which ran smoothly.  Then I plugged the 2 prong plug into a garage outlet and the gen continued to run smooth.  Turned on the breaker in the caretaker house and the lights worked there.  Turned on the house breaker and the generator bogged a bit because of the ref compressor firing up but continued running fine.

 

When power comes back just turn off the fuel petcock and let it run out of gas to clear the carburetor, turn off the on switch if your gen has one.  Unplug the gen or switch off the gen breaker if you have one, and turn on the main breaker.  Easy.

 

Now doing it my way using a typical plug, I can take it to my friends apt and plug it in there which I did.  Just turned his main off, plugged in to a handy outlet and done, no wiring into his breaker box needed.  And when I need power on a remote corner of my lot I can just take the gen out there with no need of 100mtr of extension wire.  I should be able to use one power tool on it. All I need to bring out is the gen the tool(s), and the female end of the extension cord. Plug the gen and the tool into the female socket and walla.

 

I think my gen is a Creston brand and bought from Ace. The wanted me to buy a ltr of oil to test it so I told them I have oil at home, new oil for my multicab, and would just take it and bring it back if it didn't work which they were ok with. The tank holds 6 ltr and ran 4+ hours before it died but I noticed a good bit of gas still in the tank so I put a small block under the right side to tip the tank towards the carb. I filled it and ran it several hours before shutting it off for the night. Then it ran quite a while the next day before the power came back.

Edited by SkyMan
  • Like 2
Link to post
Share on other sites
stevensanph

So, you just simply ended up plugging the gen into a regular wall socket?

I guess as you were able to turn the breaker off at the inlet point at the meter you can keep the power seperate.  That does sound a nice cheap/easy solution for backup emergency power though... 1100w gens are pretty damn cheap.

 

In my house I have a regular breaker box.  If I turn off the main breaker with the incoming mains power, would the other circuits in the house work with the gen plugged in as you described (my understanding is you did this at a friends with a regular box)

Edited by stevensanph
Link to post
Share on other sites

To the OP - if you install any generator near your house (and neighbours), make it a quiet one (or the quietest you can find). 5kVA should be plenty for a small house - even with one window type a/c unit. 

 

We have a cheaper (30k approx), 5kVA, Chinese, diesel model. It really vibrates and is the noisiest thing for miles around. The one appliance that causes it to change engine note noticeably is the well pump. It is going to cost me some amount to try to quieten it down (unless I can find a cheap quiet one!). Thick rubber pads, floor bolts, egg-carton-like soundproofing, mufflers and welding are all in my future.

 

Changeover from mains to genny and back again is simple. The mains feed and the genny feed go to opposite sides of a big on-off-on switch (I forget the poles/throws terminology). The output from the switch feeds the breaker panel. It was a simple hookup for a non-qualified but brave "electrician". I say brave because he was prepared to do this as a retrofit which meant changing where the mains feed connected.

 

Oh and now has to be the worst possible time to buy something like a  generator....

Edited by Paddy
  • Like 1
Link to post
Share on other sites
Mandingo

3-5Kw should be fine if you forget the AC.  What makes you say it is underpowered?  I bought a 1.1Kw gas generator and it ran our smallish ref/desktop computer with LED monitor and lights no problem.  I did not turn on the microwave, coffee maker, or use any power tools.  What is the monthly KWH usage?  Ours is about 220KWH or 7.33KWH/day and that includes power tools, welder, etc.  If you figure most of your usage is during 12 hours of the day that's still under 650W average usage. 

I am being told it is underpowered, kind of difficult getting all the facts with "this person saying that person said this" and then being translated. I do know that since there is no power there, lots of people using it  and it not being the highest quality unit to begin with it days are numbered. Rather upgrade to a better unit before we actually need it.

 

I have been thinking about getting a new generator for a long time, this is the excuse I needed I guess to justify getting one . The old unit can go to my wife's parents place up in the mountains and the new unit to my wife's place were her boys stay. I really want something quieter and one that has more power, like I said,  I do occasionally need to run a aircon at least until I get adjusted to the weather.

Edited by Mandingo
Link to post
Share on other sites

A 5kva genset will give you 20A @ 240V which is about 96% loaded.

A 8kva genset will give you 33A @ 240V which is about 99% loaded.

 

If you want to run the aircon, fridge, lights, and lounge, 8kva would be the go.

It will comfortably give 3 X 10A circuits.

 

That way you can also alternate between running the kitchen and laundry.

 

As I stated earlier, you have to allow for when 2 compressors start at the same time.

 

And in reality, I would only want to pull 25A max continuously from an 8kva genset.

 

Heavy loading only wears things out faster...

  • Like 1
Link to post
Share on other sites

SkyMan said "I'm going to tell you what I did and there are probably some here that will tell you I'm insane

but it worked well for me."

 

I don't understand why you didn't just plug your small fridge directly into the genny via extension cord.

 

You are playing a dangerous game there... 

 

If you lived alone, what you are doing may be safer. Depends on the beers.

 

Umping my friend...

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use, Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue..