the county had a 30kw gen set installed at their comms tower several years ago. to save on expense, they elected to have their on staff sparky set it up. gas co dropped off the tank, gen company dropped off the genny. teh sparkies doing the building wiring setup teh transfer switch, but we told NOT to touch teh gen set itself. long story short, it took 4 months for the genny to run correctly, as the guy never did anythign but make the physical connections. at first it would nto even run, turns out that you had to have a second LP regulator for that model. then it would run, but the UPS's inside stayed on battery because it was runnign at 200v 70Hz! so yes, major tuning MAY be required on site.

as far as hooking it up. i always prefered a ATS that you pull the main into, then jumper out and feed the main breaker of a sub panel. i don't like the ones with multiple breakers in the ATS. you have POCO and genny in, then 1 feed out to the house panel. if you go moving existing circuits to a new panel, you will likely find that many of them are too short to reach.

What do you mean by the terms "standard" and "service disconnect"? I'm guessing that you are using the term "standard" to mean the light duty transfer switches that are used by Generac and others- having a multitude of individual breakers. I will further guess that a "service disconnect" switch means an industry standard transfer switch- having a 100A capacity and fed from the generator or utility to an existing 100A subpanel.

If I'm interpreting you correctly, my recommendation is for the standard 100A switch. The genset can take care of itself, it should have its own main line breaker at minimum, and some will have a field breaker as well. FYI- most genset makers require the initial startup to be done by an "authorized" person if you want warranty coverage.

The Standard ATS's have individual breakers in them - and you must select 12 or 16 circuits to back up.

The Service Disconnect looks like it has one large breaker in it. You would feed main power to the ATS - in my case a 100 amp feeder line coming from the main service panel that is tied into my sub-panel with all my branch circuits that I want backed up. Then out of the ATS - you feed the the sub-panel.

It seems like the Service Discconect is not only easier to hook up, but is also does not have the limitation of 12 or 16 breakers that the Standard ATS's have. Can anyone explain why I would want one over the other?

Thanks

"not only easier to hook up, but is also does not have the limitation of 12 or 16 breakers that the Standard ATS's have."

That pretty much sums it up. Something like a 100amp ASCO 165 would probably do nicely.

wayne

thanks very much. I will check out the asco 165.

Hi,

I went through this exercise two years ago to install a Cummins Onan 20kw Generator.

You are correct in that there are lots of trades involved here:

1) Electrician
2) Plummer for Gas
3) Gas propane supplier
4) Builder for concrete pad
5) Generator / Tunner

I did not buy my generator from a turnkey place because those places are expensive. I bought my generator from Costco. It took a bit of doing but I think it came out O.K.

The first issue was when the generator was delivered it was missing a few parts. Small issue in that a hinge pin was missing. A bit of going back and forth between Costco and Cummins Onan. Costco in general had no clue, you get the usual customer serrvice rep more accustomed to handling pots and pan returns.

Cummins Onan was another story. These guys although dificult to get to the right person via Costco. Once there they were very good. In total they came to my place four times. 1 came out to check over the genset, 2 replace ths missing pin (free both times). I paid for them to come out for on-site turn on and tuning, And one more time to fix on a Goverment recall notice (free). I paid only once for the turn on visit. They were prompt and responsive on the phone was good. I recommend them,

The installation was handled for me by a Electrician who had generator installation experience. The Cummins Onan was over 1000 lbs in weight, so my electrician used a small back hoe to put it in place on concrete pad. He also did all the trenching for the gas lines. The propane gas tank we had to purchase from the propane company. They hooked up the tank and put in the gas line and installed a gas regulator for the generator. The propane company were NOT willing to hook up the gas regulator to the generator! So we had to get a plumber to do the final hook up. My electrician had a licensed plummer to do that bit. Took him all of 30 mins and was a buddy so the charge was not too high $US 200 I think,

Final turn on was done by Cummins Onan. They came checked the wiring and the tuning, My electrician was also there to make sure no back feeding to the local utility side.

My ATS came with the generator as a set. The ATS has a number of additional hookups for my genset.

1) Heater on 120v to keep the genset warm for fast start up reduced engine wear
2) Trickle charger cable to make sure car battery in gen set constanlly topped up. Something like a battery tendor / charger.
3) power cables for output power. (not switched neutral)
4) Various engine start etc controll cables.

My supply is 400 amps coming into two panels. My electrician rewired one of the 200 amp panels to be the 'BACKED up' panel. All the circuits that we wanted genset powered was on one sub-panel. The ATS then controls power to that panel. The non-backed up circuits were moved off to the other not backed up sub panel.

I would advise that you ask your electrician to also install a whole house surge supressor on the incoming power lines. That way a lightning strike will not take out your genset, or at least less likely to....

The whole exercise took about 4 months from start to finish. The electrician was the general contractor and I think did a good job in coordinating all the trades.

The only bit that I did was the gardening, planted a new lawn over all the earth excavations :) so yet another trade .....

Best, Mike.

Mike

Thanks so much for all the detail in the steps involved. My process will be similar - although I already have a 500 gallon propane tank burried - it is there for cooking, tankless hot water, dryer, etc. - so plenty of capacity to support a generator running for a few days.

I wanted to buy the generator at Costco - but they stopped carrying the smaller 12kW Onan - which is what I want and all I really need. That is why I am looking at the 12kw and 17 kw Kohler - which I can get from Lowe's or an on-line source I found (Norwall.com)

I will be making the pad - that is pretty easy. I have an electrician who can hook up the transfer switch - which I now know will be a Service Disconnect type which should simplify the connections. I know about the heater and battery charger circuit - and my syb-panel with all my backup circuits could accomodate that feed.

I planned for this from the very start of the house build so the sub panel with all my backup circuits was positioned on an interior wall in the basement very close to where the genset will sit outside, and there is a gas line very close as well. When I had the propane connected, i told Amerigas what I was planning to do and they put in a larger regulator on the service entrance so I won't have to change that.

The last 2 pieces of the puzzle for me are how to get the 500 pound beast from my driveway to the back side of the house where the pad will be and the tuning - which has to be done to make sure the voltage & frequency is properly set.

Thanks again for the help.

When it is delivered they can place it where you want with their forklift, as long as they can get the lift to the area.

Another suggestion to get it moved where you want is to call a tree company. They have some pretty good dollies, etc for moving heavy trees where they need to be planted. All you will need is a few guys to lift it on and off the dolly. I hired them to move a very heavy refrigeration unit. Worked out well and was a whole lot cheaper than a crane!

A lousy 500 pounds and you need to hire a tree company or a crane? Geez, what's the world coming to?

If, working alone, a 61-year-old man (me) can get an

Bah, humbug. Nobody has an patience anymore. :-)

But, yeah, if the terrain is suitable for a forklift, you may want to dicker about that when you make arrangements because they might want to charge you something like an extra $100 for that.

Cheers and good luck. Been an interesting thread to follow.

Merry Christmas, Tom

Gents

Thanks for the suggestions. If I can pay the delivery guy a few extra bucks to place it on the poad - I will certainly do that.

Terrible Tom - can you give me some details on how you would move the unit by yourself - I am intrigued.

The unit would be delivered to a flat gravel driveway area. I would then have to move it around the corner and down a hill - moderately slopped - about 100 feet away from the driveway area. The ground will probably be frozen by the time I get around to doing this. The terrain is fairly smooth down the hill. It get's a little bumpy near where the pad will be - but not too bad.

Thanks for the help.

Tom...I am impressed!! We're similar in age, and I would hate to have to do what you did...and I'm not in bad shape either! Very innovative thinking by the way.