Generator - Stand Alone Feed Circuit Help? - Electrical - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 12-11-2010, 02:06 PM   #1
Newbie
 
Join Date: Dec 2010
Posts: 4
Rewards Points: 10
Default

Generator - stand alone feed circuit help?


I plan on installing an emergency generator using a stand alone circuit (no attachment to the service panel) from my detached garage where the generator will stay to the house. I need this generator to run my sump pump if the POCO goes out or I get 18 inches of water in my basement. This would normally happen in the warmer months here in PA. I also plan on using the same feed to my oil furnance during the winter months if the power goes out. The pump and furnace will never be used at the same time. I have attached a drawing of what I'm going to do to simplify my discussion.

The Generator is a Champion 4000W startup, 3500W running, one 120V, 30A, L5-30R receptacle with a 25 A breaker built in (non-GFI). The gen to pump distance is 115 feet. I plan to burry the 100 ft cable (UF-B 6/2 with ground) through metal conduit from the garage to the house (70 feet, remaining 30 feet in the house), then Romex (6/2 with ground, 15 feet) from there to the pump. On the drawing at the first X I plan to split off another Romex 10/2 with ground to the furnace. The final receptacle at the pump with be a standard 20A duplex. The pump is a 1/3 hp Teel submersible, It currently runs fine on a 20A duplex receptacle controlled by a 20A TD breaker, I recently controlled the pump with a non-TD 20A breaker, filling the pit with water to have max start current and no trip took place. Teel pump specs are 29A startup current, 6 running. My clamp on A-meter can't record and hold peak, I saw 12A on the screen at startup and then 6A running. The oil furnace with 2 circulating pumps pulls 10 A when running, this is controlled by a 15A TD breaker with no problems. I plan on using two L5-30R receptacles at the furance, one tied to to the POCO and one to the Gen circuit, using a L5-30P plug tied to the furnace system so I can manually switch between POCO and GEN.

Does this sound OK so far?

My questions....

1. I'm trying to keep the cost down. I can't purchase one single length of 125 feet of UF-B, I can only get 100, 50 and 25 ft. If I use the 100 foot length I would need to splice in an additional 15 feet (from the 25 foot roll) at the second X in my drawing. Are 2 splices (both X points) of the 6/2 cable too many? I'm also assuming that I need to splice in a number 12/2 short length to the 6/2 to connect to the pump 20A duplex receptacle also. I can eliminate the second X splice by terminating the 100 foot feed at the first X and splicing in the 50 foot roll (additional cost over the 25 foot rool) if this is a better choice.

2. The generator will be grounded at the frame with a grounding rod. The feed from the generator inside the garage is from a 10/2 w/gnd 5 ft cable connected to a L5-30P inlet box to the UF-B 6/2 underground cable to the house. The Gen has a floating neutral (no neutral to ground bond), ground is to the frame. Currently my furnace circuit to the service box is a neutral bonded to ground at the service box. When I switch over the furance to the gen circuit it will be a floating neutral, is this a problem?

3. The furnace uses Honeywell controllers, they are 13 years old, nothing fancy, no computer programmed thermostat, etc. the specs on the Gen states total harmonic distortion (THD) is less than 5%. Will the controllers function ok?

4. Should the conduit be grounded to the same rod as the generator frame? Or no conduit ground?

5. What are the best splice connectors to use with 6/2 cable?

Any other comments and suggestions would be appreciated.

Thanks,


Bob P.
Attached Thumbnails
Generator - stand alone feed circuit help?-gen-house.jpg  

Advertisement


Last edited by FussyBob; 12-13-2010 at 11:14 PM.
FussyBob is offline   Reply With Quote
Old 12-11-2010, 03:39 PM   #2
the Musigician
 
DangerMouse's Avatar
 
Join Date: Jul 2008
Location: I'm right here!
Posts: 10,404
Rewards Points: 2,000
Default

Generator - stand alone feed circuit help?


Quote:
Originally Posted by FussyBob View Post
I can't purchase one single length of 125 feet of UF-B, I can only get 100, 50 and 25 ft.
Why not? HD sells all their wire by the foot as long as you need it to be.

DM

Advertisement

__________________
[SIGPIC][/SIGPIC]Click here to see some of my original magic tricks and trick boxes!
DangerMouse is offline   Reply With Quote
Old 12-11-2010, 03:53 PM   #3
Newbie
 
Join Date: Dec 2010
Posts: 4
Rewards Points: 10
Default

Generator - stand alone feed circuit help?


They don't sell UF 6/2, only 6/3.
FussyBob is offline   Reply With Quote
Old 12-11-2010, 04:25 PM   #4
Electrical Contractor
 
kbsparky's Avatar
 
Join Date: Sep 2008
Location: Delmarva
Posts: 3,368
Rewards Points: 2,000
Default

Generator - stand alone feed circuit help?


If you are trying to keep the cost down, why are you wasting your money buying 6/2 UF cable? That is overkill big time. 10/2 would work just fine in this situation.

Also, using PVC conduit would be more cost-effective than metal conduit for your underground installation.

While type UF cable can be direct-buried by itself, if your soil has lots of rocks or gravel, I can agree with the added physical protection of installing it in conduit.
__________________
-KB

Life is uncertain -- eat dessert first!!
kbsparky is offline   Reply With Quote
Old 12-11-2010, 04:39 PM   #5
Newbie
 
Join Date: Dec 2010
Posts: 4
Rewards Points: 10
Default

Generator - stand alone feed circuit help?


Quote:
Originally Posted by kbsparky View Post
If you are trying to keep the cost down, why are you wasting your money buying 6/2 UF cable? That is overkill big time. 10/2 would work just fine in this situation.

Also, using PVC conduit would be more cost-effective than metal conduit for your underground installation.

While type UF cable can be direct-buried by itself, if your soil has lots of rocks or gravel, I can agree with the added physical protection of installing it in conduit.

I want the circuit to have the capability of the generator's 25A breaker, you never know what the future will be, I might need a larger sump pump. Thus at 25A, for 120 feet run, with 3% voltage drop, my calculations come to #6 wire.

I really don't want to dig to 18 inches as required for direct bury and PVC conduit as I have a ton of small stones, metal conduit requires only 6 inches deep, more my liking!
FussyBob is offline   Reply With Quote
Old 12-13-2010, 11:15 PM   #6
Newbie
 
Join Date: Dec 2010
Posts: 4
Rewards Points: 10
Default

Generator - stand alone feed circuit help?


Can anyone help in answering my 1-5 questions?


Thanks,


Bob P.

Advertisement

FussyBob is offline   Reply With Quote
Reply


Thread Tools
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Home Theater Dedicated Circuit rjschwar Electrical 20 12-16-2009 01:42 PM
Changing a 3 way circuit...using recessed lighting box as a junction box? Oxymoron Electrical 1 12-07-2009 07:46 PM
Two Different Wire gages on Same Circuit OK? Lovegasoline Electrical 5 12-02-2009 06:00 PM
Just for fun Andy in ATL Electrical 56 10-20-2009 10:33 AM
Attic fan and skylights on same circuit ok? shadango Electrical 7 06-09-2008 03:50 PM




Top of Page | View New Posts