onamission1 Posts: 21, Reputation: 0 New Member #1 Aug 21, 2009, 03:33 AM
How do I know what my generator is rated for in regards to amps ?
I do not have a nema number or a amps output rating on my generator however I do have 6.5750 on it, now what do I do for the conversion and how do I know what cord to use and what input to use? Can anyone help me, I'm thinking about running teck from the transfer switch outside to my plug but I'm stuck!! :eek:
 Stratmando Posts: 11,188, Reputation: 508 Uber Member #2 Aug 21, 2009, 06:04 AM

I don't think it is 6.5750 Watts, or 65750 watts.
Whatever the watts are, divide by the voltage 120 or 240, this will give you the AMPS.
Do you have a 30 Amp or 50 Amp receptacle on Generator?
 Missouri Bound Posts: 1,532, Reputation: 94 Ultra Member #3 Aug 21, 2009, 08:03 PM
Ohms law is how you calculate amperage, wattage at a given voltage.
Example... 120 volts X 20 amps = 2400 watts
 onamission1 Posts: 21, Reputation: 0 New Member #4 Aug 21, 2009, 10:51 PM

THis is the generator I want to install, 6800 Watt Portable Genearator ELECTRIC START

# Wattage

* Running Watts: 6800 Watts
* Maximum Watts: 8500 Watts

my plan is to mount a box on the outside of the house, with the 120-240V L14-30R inlet, so I can plug a extension cord if I need it or move the generator when I don't need it. Now my question is, do I use #6 copper for x y w and ground in a rubber jacket wire ? If that is so I am assuming x is pulling 30 amps and y is pulling 30 amps, which means that I need the 60 amp panel! Is my thinking right ? Thanks guys for you input in advanced!
 ohb0b Posts: 215, Reputation: 14 Full Member #5 Aug 22, 2009, 02:18 PM
1. You will note that 6,800 is 80% of 8,500. This means you have an 8,500 watt (Maximum) generator that has been derated 20% for continuous service.

As far as determining the amps, use Ohm's Law and Powers Law as suggested by the previous answers.

For single phase applications: P=EI
(If you had a 3-phase generator, the formula would be P=(square root of 3)EI

Solving for I:

I=P/E =6800/240=28.3 amps

If you have 120 Volt loads, balance them between the phase conductors so you do not exceed 28 amps on either leg.
For example, if you have two 20 amp loads and put them both on the same leg, you will exceed the capacity of the generator because you will draw 40 amps on one leg. Dividing the same loads between legs means each leg will see only 20 amps. Power will be the same with either setup: 20x 240 = 40x 120 =480 watts
 onamission1 Posts: 21, Reputation: 0 New Member #6 Aug 22, 2009, 08:12 PM

But can I use a 60 amp breaker split phase in the panel if the generator is pulling out 30 amps on each leg ? It's the best panel I could find! 60 amp federal pioneer
 Missouri Bound Posts: 1,532, Reputation: 94 Ultra Member #7 Aug 22, 2009, 08:37 PM
Nothing good or "best" about a Federal panel
 ohb0b Posts: 215, Reputation: 14 Full Member #8 Aug 22, 2009, 09:36 PM
Originally Posted by onamission1
But can i use a 60 amp breaker split phase in the panel if the generator is pulling out 30 amps on each leg ? its the best panel i could find !! 60 amp federal pioneer

The "30 amps each leg" is the same 30 amps, you are just measuring it on two different wires. A 60 amp breaker will not protect the generator from overload in this case.

Is Federal Pioneer (Federal Pacific in the US) still in business? They got caught faking UL/CSA test results a while back.
 tkrussell Posts: 9,659, Reputation: 725 Uber Member #9 Aug 23, 2009, 04:46 AM
Onamission is clearly from Canada, as Teck cable was mentioned in the original question.

Federal Pioneer is alive and well in Canada, and marketed by Schneider, parent company of the well known Square D brand name.

Schneider Electric Canada - Solutions, Products and Services in Electrical Distribution and Automation and Control
 ohb0b Posts: 215, Reputation: 14 Full Member #10 Aug 23, 2009, 10:56 AM
Onamission is clearly from Canada, as Teck cable was mentioned in the original question.

As long as he doesn't run it in Lumex and use Marrettes I guess its OK.
 onamission1 Posts: 21, Reputation: 0 New Member #11 Aug 23, 2009, 02:24 PM

OK so I'm going to just get a 30 amp square D panel and runn a 8 awg 3 wire plus ground to the panel from the generator, that sound right ?
 Missouri Bound Posts: 1,532, Reputation: 94 Ultra Member #12 Aug 23, 2009, 02:35 PM
Does your generator have a 120/240 twist in receptacle? This is the plug you want to use. I suspect it's a 30 amp, meaning you will have 30 amps on each leg. You can use #8 for this, and it needs to be 4 wire from the generator, two hot legs, a neutral and a ground in order to connect to your transfer switch. Perhaps one of the other members can tell me / you if a grounding electrode is required for this installation, since it is a portable generator being connected.
 KISS Posts: 12,510, Reputation: 839 Uber Member #13 Aug 23, 2009, 03:52 PM

60 Amp back fed breaker from a 30 Amp generator breaker should be fine unless I'm missing something. All wiring is proctected.
 onamission1 Posts: 21, Reputation: 0 New Member #14 Aug 23, 2009, 04:55 PM

That's what I was thinking, sure I could easly overload it if I wasn't careful because of all the empty slots. However I did just got buy a 30 amp semens panel, for 200 bucks.

So how do I know if the neutral is bonded ? Anybody know that ?
 onamission1 Posts: 21, Reputation: 0 New Member #15 Aug 23, 2009, 04:55 PM
About the ground plate, I wasn't going to install that, my friend is a master electrician and he said don't worry about it... what do you guys think ?

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