What Gauge Wire?

[my-rifle]

So I'm going to make a pig-tail to connect my 5kw/6.2kw Briggs & Stratton generator into my electrical panel. I have a workshop separate from my house that has its own electrical panel, and a 20amp 220v breaker with an outlet connected to it. My home is old, and it has a main fuse that I can pull to disconnect the house from the external grid.

What I'd like to do is to set up a platform under a roof overhang, and use it when I run my generator. I'd like to run a pig-tail from the single 20amp 220v four-prong twist-lock connector on my generator into the shop and plug it into the 20amp 220v 3-prong plug in order to back-feed the house. I'm figuring that should make the majority of my generator's power available to the whole house.

My question is what gauge wire should I get to make this connector?

 

[Blackhawk]

I'm not an electrician, so take my advice with a grain of salt. More than likely your line from the panel to the outlet is 12AWG solid wire. I would suggest that your pigtail (if stranded cable) be at least 10 AWG, and 8 AWG would be better. I personally have the same setup but use a pigtail from an old welder that is probably 4 AWG. Your type of connector will limit your wire size. Might I suggest that you use welder or dryer outlets and plugs, as they are generally heavier duty than twist lock and capable of attaching heavier wire.

 

[my-rifle]

I'm not an electrician, so take my advice with a grain of salt. More than likely your line from the panel to the outlet is 12AWG solid wire. I would suggest that your pigtail (if stranded cable) be at least 10 AWG, and 8 AWG would be better. I personally have the same setup but use a pigtail from an old welder that is probably 4 AWG. Your type of connector will limit your wire size. Might I suggest that you use welder or dryer outlets and plugs, as they are generally heavier duty than twist lock and capable of attaching heavier wire.

Thanks. The generator has only one 220v connector, and it's a 20amp twist-lock. On the other end of the pigtail I plan to use a drier-style 3-prong connector. The nice thing about the twist-lock connector is this pigtail's going to have two male connectors on it, and if someone trips over it and unplugs it from the wall there's going to be a live male connector laying on the floor.

 

[Emperor]

Man, go on the interent and go look at the resistances each wire guage can handle. Google "wire gauges". I would bet they even have sites that will tell you exactly how to do it.

 

[drumz2129]

As long as you are not making an extremely long pig tail, 10awg will be sufficient for the 20A circuit. I have a 6.8Kw/9.2Kw JD portable generator with a 30A twist lock that I use a 15' 8awg pigtail to feed into my 50amp welder circuit in my shop to supply power to the house.

 

[drumz2129]

Since it is a 20amp 240V circuit, assume you are making a 20 foot pigtail:

From http://www.southwire.com/support/voltage-drop-calculator.htm

1 conductors per phase utilizing a #12 Copper conductor will limit the voltage drop to 0.58% or less when supplying 20.0 amps for 20 feet on a 240 volt system.
For Engineering Information Only:
20.0 Amps Rated ampacity of selected conductor
1.9029 Ohms Resistance (Ohms per 1000 feet)
0.054 Ohms Reactance (Ohms per 1000 feet)
7.199999999999999 volts maximum allowable voltage drop at 3%
1.389. Actual voltage drop loss at 0.58% for the circuit
0.9 Power Factor

and maximum distance on 12awg:

A maximum distance of 103.677 feet will limit the voltage drop to 3% or less with a #12 Copper conductor delivering 20.0 amps on a 240 volt system.
For Engineering Information Only:
20.0 Amps Rated ampacity of selected conductor
1.9029 Ohms Resistance (Ohms per 1000 feet)
0.054 Ohms Reactance (Ohms per 1000 feet)
7.199999999999999 volts maximum allowable voltage drop at 3%
0.9 Power Factor

 

[Ironman26]

Since it is a 20amp 240V circuit, assume you are making a 20 foot pigtail:

From http://www.southwire.com/support/voltage-drop-calculator.htm

3 conductors of 10 ga. or 8 ga......If it were me I would run 3 conductors of 8 ga. with a 10ga ground to be on the extra safe side....

 

[dantheman]

If it's a short run , 10 awg is fine . The plug is only rated for 20 amps , so #8 is a little overkill , unless you get it cheap ( or free ) .
Hell , #8 might not fit into the terminals of your 20 amp plug . Check before you spend the money .

 

[Ironman26]

Thanks Dan, I didnt think about the #8 not fitting into the terminals on the plug..!

If it's a short run , 10 awg is fine . The plug is only rated for 20 amps , so #8 is a little overkill , unless you get it cheap ( or free ) .
Hell , #8 might not fit into the terminals of your 20 amp plug . Check before you spend the money .

 

[Yrdawg]

So I'm going to make a pig-tail to connect my 5kw/6.2kw Briggs & Stratton generator into my electrical panel. I have a workshop separate from my house that has its own electrical panel, and a 20amp 220v breaker with an outlet connected to it. My home is old, and it has a main fuse that I can pull to disconnect the house from the external grid.

What I'd like to do is to set up a platform under a roof overhang, and use it when I run my generator. I'd like to run a pig-tail from the single 20amp 220v four-prong twist-lock connector on my generator into the shop and plug it into the 20amp 220v 3-prong plug in order to back-feed the house. I'm figuring that should make the majority of my generator's power available to the whole house.

My question is what gauge wire should I get to make this connector?

Basicaly what I did, works great...the power co. guys even looked at it after an outage and they didn't run off screaming. I used a 50 A breaker to backfeed buss and I turn off the 200 main to shed the utility.

Remember to turn off your WH and Condensor before you fire up the house on stand by.

 

[Tate]

For 20A at ~20' #12 AWG wire is all you need. I am an electrical designer and until recently, a licensed electrician.

 

[H.Bear]

Nevermind...didn't see that it was 20 amps.

 

[DWT]

With a generator rated at 6KW, you will not be able to run all the circuit in the house, especially the central A/C, if applicable. If I were you, I'd limit the load on the generator to a 120-volt window A/C unit, refrigerator, TV, and a couple of lights. Trying to run too many appliances at once is a recipe for disaster. Please be careful and make sure you have a good earth ground connection. Also, I would advise connecting the pigtail from the generator directly into your electrical service fuse box, below the meter, and make the pigtail as short as possible to minimize overheating. 10 feet or less, if possible.

 

[stag0608]

#12 is good for 20 amps all day long make sure it is fused 20 amps

 

[my-rifle]

With a generator rated at 6KW, you will not be able to run all the circuit in the house, especially the central A/C, if applicable. If I were you, I'd limit the load on the generator to a 120-volt window A/C unit, refrigerator, TV, and a couple of lights. Trying to run too many appliances at once is a recipe for disaster. Please be careful and make sure you have a good earth ground connection. Also, I would advise connecting the pigtail from the generator directly into your electrical service fuse box, below the meter, and make the pigtail as short as possible to minimize overheating. 10 feet or less, if possible.

Yeah I know about the central AC. I've already run a load test for six hours using the 2 6amp fridges and the two 6amp and one 8amp A/C units. I shut down the central AC. That left plenty of power for lights and one computer running on a UPS. The generator is made to take a starting load up to 6.5kw. We've replaced most of the lights in the house with fluorescent bulbs, so they draw almost nothing.

 

[themcfarland]

look up esso cord.. its probably the best to use ..

 

[my-rifle]

I really wish I could wire it directly into the panel, but I'm not looking to pay some electrician a couple thousand dollars to wire this thing. I'm looking for a solution I can install myself. Every time I pass a glance at a plumber or electrician I get a $1000 bill for it.

 

[dantheman]

look up esso cord.. its probably the best to use ..

SO cord .

 

[themcfarland]

Thanks Dan, I was close.. lol

 

[my-rifle]

SO cord .

That explains why I couldn't find it