# 3 prong vs 4 prong connector



## Tatertot (Jan 22, 2021)

Hello, I want to get a small generator to use in my garage during power outages, and already have figured out that one with around 3,000 watts will be big enough to power what I need, which is a small refrigerator and 2 or 3 other things, none are 240. My question is, what is the difference between the 3 prong vs 4 prong connector on the generator to plug a cable into it with at the other end of the cable it fans out to 4 plugs to plug my different things into? The reason I ask, is I found a small 3500 watt portable generator the just has a 3 prong only, not a 4 prong, at reasonable price.


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## Old man here (Nov 5, 2020)

Tatertot said:


> Hello, I want to get a small generator to use in my garage during power outages, and already have figured out that one with around 3,000 watts will be big enough to power what I need, which is a small refrigerator and 2 or 3 other things, none are 240. My question is, what is the difference between the 3 prong vs 4 prong connector on the generator to plug a cable into it with at the other end of the cable it fans out to 4 plugs to plug my different things into? The reason I ask, is I found a small 3500 watt portable generator the just has a 3 prong only, not a 4 prong, at reasonable price.


Does this help?








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Also:


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## exmar (Jun 29, 2015)

If I understand your question, you just want to power 120V loads in your garage? If so, forget 4 prong that's only for 120/240V connections. Also, do you plan on just running extension cord(s) and not tieing into your load center? If so, just look at the receptacles on your intended generator and see what you need in extension cords. e.g. You have two outlets or four receptacles, probably NEMA 5-15 from the chart above provided by Old Man. So, four extension cords, probably limited to 15A for each pair. Look at the circuit breakers on your generator probably 15A X 2 or one for each outlet. How many extension cords you want to run is up to you. If you go with extension cords you should drive a ground rod to ground the generator-strongly recommended. Also required by NEC.

Clarification: "outlet" means a duplex receptacle or two places to plug in extension cords.

If you want to use the existing wiring and outlets in the garage, that's a whole 'nother thing, requiring a disconnect switch, generator inlet connection, etc. IME generators in that size you'll have to be creative in your wiring connection to get all 3,000 watts as there may not be a 120V/30A outlet on the generator.


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## Tatertot (Jan 22, 2021)

exmar said:


> If I understand your question, you just want to power 120V loads in your garage? If so, forget 4 prong that's only for 120/240V connections. Also, do you plan on just running extension cord(s) and not tieing into your load center? If so, just look at the receptacles on your intended generator and see what you need in extension cords. e.g. You have two outlets or four receptacles, probably NEMA 5-15 from the chart above provided by Old Man. So, four extension cords, probably limited to 15A for each pair. Look at the circuit breakers on your generator probably 15A X 2 or one for each outlet. How many extension cords you want to run is up to you. If you go with extension cords you should drive a ground rod to ground the generator-strongly recommended. Also required by NEC.
> 
> Clarification: "outlet" means a duplex receptacle or two places to plug in extension cords.
> 
> If you want to use the existing wiring and outlets in the garage, that's a whole 'nother thing, requiring a disconnect switch, generator inlet connection, etc. IME generators in that size you'll have to be creative in your wiring connection to get all 3,000 watts as there may not be a 120V/30A outlet on the generator.


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## Tatertot (Jan 22, 2021)

Thanks for getting back to me. I wanted to run one chord like this, CHAMPION POWER EQUIPMENT 25 fts. 30 Amp 125/250-Volt Fan-Style Flat Generator Extension Cord-100437 - The Home Depot , into the garage, off a generator like this WEN 6000-Watt Portable RV-Ready Gas Powered Portable Generator with Wheel Kit, CARB Compliant-GN6000 - The Home Depot.


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## Tatertot (Jan 22, 2021)

My error, it’s not the generator above, but it is this one, WEN 4,750/3,800-Watt 120-Volt/240-Volt Dual Fuel Gasoline and Propane Powered Electric Start Portable Generator w/Wheel Kit-DF475T - The Home Depot , which is 3,800 watts, to the cord I have above.


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## exmar (Jun 29, 2015)

That'll work. As I said, look at the generator and see what you have to work with. Ground rod still needed. I thought you were looking at an older/used unit some of those didn't provide that connection.


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## Old man here (Nov 5, 2020)

Tatertot said:


> My error, it’s not the generator above, but it is this one, WEN 4,750/3,800-Watt 120-Volt/240-Volt Dual Fuel Gasoline and Propane Powered Electric Start Portable Generator w/Wheel Kit-DF475T - The Home Depot , which is 3,800 watts, to the cord I have above.


The cord you referred to above will work with the generator listed in this post. 
This generator is listed as having a NEMA 30 Amp twist lock (L14-30R) outlet and the cord is designed just for this use.
Good to go.


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## Tatertot (Jan 22, 2021)

Thanks to all that helped!


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## tabora (Sep 6, 2018)

Old man here said:


> This generator is listed as having a NEMA 30 Amp twist lock (L14-30R) outlet and the cord is designed just for this use.


Yup, 2 outlets will be fed from one hot leg and the other two will be fed from the other hot leg. That's what I used before I installed a transfer switch and still use it from time to time to power discrete loads away from the house/barn. That one is nice, since it's flat. If you run it in through a window, use a towel or a strip of pipe insulation to seal the opening well and keep the CO out!


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## Tatertot (Jan 22, 2021)

tabora said:


> Yup, 2 outlets will be fed from one hot leg and the other two will be fed from the other hot leg. That's what I used before I installed a transfer switch and still use it from time to time to power discrete loads away from the house/barn. That one is nice, since it's flat. If you run it in through a window, use a towel or a strip of pipe insulation to seal the opening well and keep the CO out!


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## Tatertot (Jan 22, 2021)

Thanks, I think I will go with this setup, for my garage, can put the flat cord under the door. I understand I need to put a ground rod in to, with this setup?


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## tabora (Sep 6, 2018)

Tatertot said:


> Thanks, I think I will go with this setup, for my garage, can put the flat cord under the door. I understand I need to put a ground rod in to, with this setup?


Balance the load between the two legs. Plug into the end receptacles first. Yes, you should use a ground rod. If you're always going to use it in the same location, drive an 8 foot rod. I also have a short one I drive in where ever I use it if it's not connected to the house. I can pull it right back out with my offroad/farm jack:


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## Old man here (Nov 5, 2020)

Tatertot said:


> Thanks, I think I will go with this setup, for my garage, can put the flat cord under the door. I understand I need to put a ground rod in to, with this setup?


You should have a ground rod anytime your generator is not connected to your house power. I use one even then. 
I have a cable with large alligator clips that I connect to the generator frame bolt and ground rod before I even start the generator.
Just an old practice from my Air Force days in the early 70's when I was a crew chief on B52's.
We grounded the aircraft as soon as it landed. Grounded the aux. power unit before it was even started. That was a big generator connected to the aircraft while it was parked.


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