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Old 11-09-2012, 02:25 PM   #1
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Backup Diesel Generator, ATS, subpanel


I bought a larger commercial diesel generator to have available for family and business should we suffer a power outage of length.

The unit I bought is a commercial MultiQuip 40kw unit and has an auto-start option when line power is lost.

I was hoping to be able to leave it near one of the ag barns hooked up. (It is on a trailer) Distance is around 250' from the house. But I cant think of any code compliant way to do it.

So I think my only option is to put an ATS sub-panel in the house and move the circuits I care about to it, and then have this generator feed that panel, right? It's going to make some of my panels have nothing in them anymore

I guess my other option is to put in a whole-house ATS in, but my understanding is that whatever generator you hook up to it, has to be able to supply the whole system capabilities, which in my case is 400 amps.

The unit I bought is a MultiQuip DCA70SSJU. In Single phase (zig zag) it is rated for 44KW
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Old 11-09-2012, 02:59 PM   #2
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Backup Diesel Generator, ATS, subpanel


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Originally Posted by AndrewF View Post
put an ATS sub-panel in the house and move the circuits I care about to it

That is the route I would take.

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Old 11-09-2012, 03:24 PM   #3
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Originally Posted by Missouri Bound View Post
That is the route I would take.
I disagree.

Most of my customers, those who want 7-20Kw automatic generators or even those with smaller 5,500w portable generators, would like the ability to power any circuit in the house. That is why Interlock Kits have become so popular and no one wants the 6-10 circuit sub panels anymore.

The OP has a 44Kw generator, which is monstrous for a house and is most likely very close in size to his PoCo electrical service. There is no reason why he shouldn't have an ATS capable of powering his entire house.

OP, what size service do you have on your house, 200A? If so, I'd recommend getting an 200A automatic transfer switch. With your size generator, you wouldn't even have to worry about load shedding.
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Old 11-09-2012, 03:42 PM   #4
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Backup Diesel Generator, ATS, subpanel


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Originally Posted by Rza View Post
I disagree.

Most of my customers, those who want 7-20Kw automatic generators or even those with smaller 5,500w portable generators, would like the ability to power any circuit in the house. That is why Interlock Kits have become so popular and no one wants the 6-10 circuit sub panels anymore.

The OP has a 44Kw generator, which is monstrous for a house and is most likely very close in size to his PoCo electrical service. There is no reason why he shouldn't have an ATS capable of powering his entire house.

OP, what size service do you have on your house, 200A? If so, I'd recommend getting an 200A automatic transfer switch. With your size generator, you wouldn't even have to worry about load shedding.
If I had a generator that size, I'd be wiring the whole house as well.
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Old 11-09-2012, 03:43 PM   #5
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Backup Diesel Generator, ATS, subpanel


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OP, what size service do you have on your house, 200A?

He states that he has a 400 amp service.
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Old 11-09-2012, 05:04 PM   #6
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Backup Diesel Generator, ATS, subpanel


Quote:
Originally Posted by AndrewF View Post
I guess my other option is to put in a whole-house ATS in, but my understanding is that whatever generator you hook up to it, has to be able to supply the whole system capabilities, which in my case is 400 amps.

The unit I bought is a MultiQuip DCA70SSJU. In Single phase (zig zag) it is rated for 44KW
It does not have to handle the whole service, it has to handle basically the calculated load. It is written here:
Quote:
702.5 Capacity and Rating.
An optional standby system
shall have adequate capacity and rating for the supply of all
equipment intended to be operated at one time. Optional
standby system equipment shall be suitable for the maxi-
mum available fault current at its terminals. The user of the
optional standby system shall be permitted to select the
load connected to the system.
This means if you have a 400A panel the transfer equipment must be 400A. But the gen must be able to supply the "normal" load of the home. In your case it is HIGHLY doubtful this is over 200A.
Most people with 400A services use two 200A panels and designate one as the generator panel with the critical/desired circuits, with a 200A transfer switch for just that panel.
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Old 11-10-2012, 01:09 AM   #7
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Backup Diesel Generator, ATS, subpanel


Quote:
Originally Posted by Speedy Petey View Post
It does not have to handle the whole service, it has to handle basically the calculated load. It is written here:


This means if you have a 400A panel the transfer equipment must be 400A. But the gen must be able to supply the "normal" load of the home. In your case it is HIGHLY doubtful this is over 200A.
Most people with 400A services use two 200A panels and designate one as the generator panel with the critical/desired circuits, with a 200A transfer switch for just that panel.
On the second part where SpeedyPete posted that part is pretty common set up with 400 amp service with two 200 amp panels and I have done the same way as he described.

It is cheaper just use the 200 amp transfer switch than try to get a 400 amp transfer switch the cost will get ya very fast.

As far for the OP's generatour set up he will have plenty power without issue at all that is more than it will be used at once when you have all the normal stuff going on.

I have 20 KW slow speed diesel generatour and it did handle the load without issue at all with no load shreading at all.

Merci,
Marc
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Old 11-11-2012, 06:46 AM   #8
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Backup Diesel Generator, ATS, subpanel


Thanks all.

Yes, I have 320/400 amp service via two 200 amp panels, each 200amp panel then has a 100 amp sub. One goes to the basement and has all the basement, the air handler, and the 25kw backup electric heat for the HP.

The other 200amp panel's 100 amp subpanel is in my workshop, 200' from the house.

I had looked at the price for 400amp ATS, and OUCH!

I do not need to be able to run the 25kw backup electric heat, but I would like to be able to run the HP when possible. (Our 2nd stage heat is a boiler, and 3rd is the 25kw)

My outdoor HP unit is connected to one of the 200amp panels on a 50 amp breaker.

So, my next issue was finding an ATS with load center rated for 200amps, doesnt seem to be common. I guess I could get one of the 100 amp ones, and shift what I need to it, and hang the basement sub off of it so we can run the AH.

Yes, it is a big generator, but the price was affordable....under 5k. I priced out a 17-20kw Kohler LP generator, but by the time I bought the generator, a 250+LB LP tank and buried it (I have equipment to do that), ran the copper lines....it got way more expensive than this 45kw unit. Yes it is "too" big for my house, but not too big to share power with some neighbors....although they'll have to deal with voltage drop for the distance they are from me.
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Old 11-20-2012, 05:05 PM   #9
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I am finding conflicting information on cable size.

The generator has several 50amp twist lock outlets.

When I initially looked up cable rated for 50 amp, it comes up as being 6 gauge. Most RV cables are 50 amp 6 gauge.

However, when I look at some of the manufacture websites for 6/4, they list it as being rated for 45 amps.

Which is correct?

The price point between 6/4 and 4/4 is pretty hefty, so I only want to do this once.
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Old 11-20-2012, 05:24 PM   #10
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That's a 40kW generator (about 167A), so you're not going to be using the 50A receptacles to connect it to the ATS. They are for smaller auxiliary loads only. Your main connection needs to be with a cable hard-wired to the terminal block in the generator. You can install cam-lok connectors if you want it to be removable.
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Old 11-20-2012, 07:39 PM   #11
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Originally Posted by mpoulton View Post
That's a 40kW generator (about 167A), so you're not going to be using the 50A receptacles to connect it to the ATS. They are for smaller auxiliary loads only. Your main connection needs to be with a cable hard-wired to the terminal block in the generator. You can install cam-lok connectors if you want it to be removable.
Or you can use the larger pin et sleeve connector they do come in larger verison if you going to run full load either camlockers or pin et sleeve is most common methold used on portable unit and yeah there are few time you can hardwired them as well.

It much safer to use the camlocker or pin et sleeve connectors due you will really reduce the chance get it crossconneted at all.

So let me post the photo what it look like.,



Please note there are few differnt verison and style they will be using on this one.

Now for next one pin et sleeve connector look like.,



Again this do come few differnt size and conferations this something we used all the time over here ( in France ) but it pretty common over at North Americiane side as well.

Both items are not cheap but they do justifed the cost when you use those big ones.

Merci,
Marc
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Old 11-20-2012, 07:43 PM   #12
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this is exactly how i wired mine.

400 a service via 2 200a panels.
17kw gen sends power to a terminal block with then sends power to a 200A ATS and a 200a Manual txfr switch.

the ATS then feeds the 200a panel with general house circuits (all lighting, outlets, appliances, water heaters etc)...the manual txfr switch feeds the other 200a panel where i have 11 tons of a/c and a pump circuit (non critical pump).

works like a charm and the 17kw can power the whole house and start the largest ac unit simultaneously (5ton)....the two 3ton units are no problem at all.

I did price a 400a ats and and they were about 3000.00
Quote:
Originally Posted by Speedy Petey View Post
It does not have to handle the whole service, it has to handle basically the calculated load. It is written here:


This means if you have a 400A panel the transfer equipment must be 400A. But the gen must be able to supply the "normal" load of the home. In your case it is HIGHLY doubtful this is over 200A.
Most people with 400A services use two 200A panels and designate one as the generator panel with the critical/desired circuits, with a 200A transfer switch for just that panel.
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Old 11-20-2012, 08:05 PM   #13
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Backup Diesel Generator, ATS, subpanel


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He states that he has a 400 amp service.
Do you think anyone could afford a 400 amp continuous electric bill? how about 100 amp continuous?
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Old 11-20-2012, 08:09 PM   #14
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Backup Diesel Generator, ATS, subpanel


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Do you think anyone could afford a 400 amp continuous electric bill? how about 100 amp continuous?
I am not suprised with that with the cost.

The worst is when someone have to rent a big arse generator which I am talking couple megawatts size the last one I have done is 3 MW basically it the same size as med-large locomotive engine is and they can gulp the gazoil ( diesel fuel ) pretty fast at full load.

Merci,
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Old 12-03-2012, 07:23 PM   #15
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Ok, I bought a pine & sleeve 100 amp welding outlet and plug to use as my means of hooking the generator up to the house. I also bought some Type W #1 cable to make up tails for the generator with camlok on the ends.

I then bought 4/4 Type W cable. One end will have the pin and sleeve plug on it, the other end will have my camloks. I will use this cable to feed from the generator to the house. The camlok connections will be made inside the generator cable area via the main lugs, not the 50amp twist locks. So they will not be in the elements.

I then plan to run the 100 amp feed thru a 100 amp disconnect, then to my Kholer 100 amp ATS with integrated load center.

The ATS does not have a main breaker, hence my plan to put a 100 amp outdoor disconnect for the generator side.

Where I am now confused, is the ATS only switches the two main lugs, not the neutral. As I am reading up on this, I am confused on the proper way to handle the grounding/bonding for the circuits that are supplied from the ATS.

My plan is to feed the ATS with a 100 amp feed from one of my main 200 amp panels, then shift over the essential individual circuits as well as the 100 amp basement subpanel which has the air handler on it.

Since my generator does NOT have the neutral and ground bonded together, I believe I am ok with the neutral being tied into the grid.

Let the learning continue . . .

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