generator with transfer switch

Reply

  #1  
Old 11-18-12, 08:48 PM
Member
Thread Starter
Join Date: Nov 2012
Location: usa
Posts: 10
generator with transfer switch

i am looking at getting a generac with a 200 amp load sheding transfer switch . i have a 200 amp main panel with a 100 amp sub going to basement from it . the sub has my well sump pumps a/c 4 ton and a freezer .also lighting and other small loads. all the transfer switches i looked at dont have anywhere close to 100 amp. i know i dont pull anywhere close to 100 amp . but are breakers interchangeable in generac transfer switches. also the main panel has my electric range and dryer but i dont think i will hook them to the transfer sw. the jenny i am looking at is 17 maybe the 20 any suggestions
 
Sponsored Links
  #2  
Old 11-18-12, 08:57 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: USA
Posts: 17,607
So you want to power just the sub or some of the main and sub?
 
  #3  
Old 11-19-12, 12:25 PM
Member
Join Date: Jun 2008
Location: VA.
Posts: 813
If you're talking about 200 amp service rated transfer switch, it doesn't have any breakers in it other than the 200 main breaker.

You'll need to install the transfer switch between the meter and your panel.

THIS will become your service and your main panel will become a sub panel, which will require a 4 wire feeder and grounds and neutrals separated.

Your grounding electrode system will need to be done at the transfer switch.

In the transfer switch on the load shed module, there are 2-a/c modules and 4 priority load connections.

The a/c module connections just break the 24 volt control to your a/c compressor (yellow wire usually)

The priority load modules are 120 volt output so, you'll need to purchase contactors of sufficient ampacity to carry the loads of the items you want to shed. Usually 40 amp double pole will be fine to break the range and dryer.

Keep in mind, these appliances will still work unless the generator will be overloaded at which point, it will start shedding load until it's adequate.

I would just go with the 20KW prepackaged with the 200 amp switch it's only like $300 more than the 17.
 
  #4  
Old 11-19-12, 01:01 PM
Member
Join Date: Jun 2008
Location: VA.
Posts: 813
This is one we've done recently. Yours should be similar. Notice that the transfer switch is installed between the meter and panel.
 
Attached Images  
  #5  
Old 11-19-12, 06:09 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,213
Hey wirenut! Excellent description of work and a good looking installation too.
 
  #6  
Old 11-19-12, 08:04 PM
Member
Thread Starter
Join Date: Nov 2012
Location: usa
Posts: 10
i think i want to power the sub using a ats the main panel would be live so a 20 kw would do whole house but i now i need to worry about neutral bonding?
 
  #7  
Old 11-20-12, 03:06 AM
Member
Join Date: Jun 2008
Location: VA.
Posts: 813
Thanks Joe!!

Jetfan: If you could use sentences, it would be easier to understand. I think if you're going to buy a 20 kw, it would be a waste not to run the whole house and manage some loads.

If you don't run the whole house then save your money and get a 100 amp non-service rated switch and a smaller generator to feed the sub panel.
 
  #8  
Old 11-20-12, 08:06 PM
Member
Thread Starter
Join Date: Nov 2012
Location: usa
Posts: 10
sub panel feed

Thanks for the reply Joe. that is a nice job. Sorry for the bad typing. I was thinking of only feeding the sub at first, But looking for a way to feed the main panel from the ats . if possible within the NEC.

The sub circuits include 4ton a/c, 2 sump pumps, Basmt refrig, freezer , well , septic pump, Projection tv and other stereo equipment.
total wattage is 19,000 for basmt sub. The main has washer, electric dryer,electric range ,main refrig , lights etc.

The sub would be the easiest to connect to generator and propane.

Main panel is on the other side of the house in garage. Any suggestions Thanks Tom
 
  #9  
Old 11-20-12, 08:15 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
With a 200 amp service and a 20 kW generator, you have enough backup power to supply about half of your loads. I would move those to a separate panel and transfer power there. The challenge will be to power that panel, not both.
 
  #10  
Old 11-21-12, 02:14 AM
Member
Thread Starter
Join Date: Nov 2012
Location: usa
Posts: 10
If i shed the A/C, i took 14,000 can i make this work somehow. Thanks
 
  #11  
Old 11-21-12, 06:26 AM
Member
Join Date: Jun 2008
Location: VA.
Posts: 813
Ah boy, here we go again. Someone thinking that if someone has a 200 amp service then they must have a 200 amp generator.

20 KW is plenty of generator.

I give up...so long
 
  #12  
Old 11-21-12, 08:59 AM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
I misspoke earlier when I said that your 20 kW gives you enough backup power to supply about half of your loads. What I meant to say was that it gives you enough backup power to replace about half of the full capacity of your service.

It's an important distinction, and I'm glad that wirenut1110 pointed it out.
Originally Posted by wirenut1110
20 KW is plenty of generator.
The answer to your question about shedding loads can be found by performing a residential load calculation. There may be other calculators available online. This is just one I found quickly, and It looks reliable. I ran it for a house I used to own, a big Queen Anne with an A/C condenser to match, and it gave me a total demand of just over 11,000 VA.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'