Home>Discussions>ELECTRICAL & LIGHTING>Running a 220v machine off a generator
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Richmond820
Running a 220v machine off a generator

Can I run a 220v jointer directly off my generator? How?

The jointer is wired 220v 12 amps. It has a 2 hp single phase 60hz motor. The min circuit size (per the mfg) is 20 amps. The plug is a 6-15 plug.

The generator is 5700/7125 watts. It has a standard L14-30R 220v 30 amp receptacle.

My garage is not wired to handle this size machine & I cannot rewire it right now (no $$$).

Can I make up an extension cord?

Any thoughts/advice are much appreciated!

A. Spruce
Re: Running a 220v machine off a generator

As long as the genny is rated at a higher load rating than the equipment drawing power, you will do fine with an extension cord (as short as possible ) suited to the task. Keep in mind that the rating of your genny is 5700/7125, that means that it's capable of 7125 watt surges, such as machine start up, then able to maintain a constant draw of 5700 under load. There is a calculation that can be used to convert watts to amps and visa-versa. Contact the manufacturer for the load requirements of the joiner to compare to your genny's output. I'll let the more electrically inclined offer the equation and how to use it properly.

Also note, that low quality genny's - i.e. most on the general consumer market, particularly those avialable from big box stores, auto parts stores, and the like - provide dirty power, meaning that the power output fluctuates wildly. If you value your equipment, you'll use a good quality generator to power it.

JLMCDANIEL
Re: Running a 220v machine off a generator

Yes, that generator should be able to handle the load with no problem. It is not likely that the power from the generator would be dirty enough to cause a problem for the motor in the jointer, and I have not seen a jointer with an electronic control.
Jack

Richmond820
Re: Running a 220v machine off a generator

Thanks for your info!

Are there extension cords with a 4 blade plug to go into the generator & a 3 slot receptacle where the jointer would plug in?

Or

Would I have to make an extension cord? How would I do it, ie type of wire etc?

Re: Running a 220v machine off a generator

no, your generator needs a seperate ground and nuetral, I wouldnt put it on a generator "long term" I would install a new outlet in your garage. Not haveing the equipment ground bonded to other metal non current carrying parts could be a real safety hazzard. Not to mention putting gass in it everytime you need it.

Re: Running a 220v machine off a generator

You can make an extension cord but the joiner will not have the proper protection because the genny breaker is a 30A. For your application we make a sub panel that plugs into the genny and then come off a the sub panel with the correct breaker.

Re: Running a 220v machine off a generator
ohmy wrote:

You can make an extension cord but the joiner will not have the proper protection because the genny breaker is a 30A. For your application we make a sub panel that plugs into the genny and then come off a the sub panel with the correct breaker.

If this were a temporary instalation that would be fine but assuming you actually did drive a seperate electrode for the prime mover (as you should) you would create two Grounding electrode systems of unknown and probably unequal potential. In a workshop enviroment where you will likely find cord and plug equipment that requires an outlet with an equipment ground you will create (or continue in this case) a difference in potential between any metal non current carrying parts efectively bonded to the equipment ground (such as the housing of a drill motor or slide saw) and the equipment effectively bonded to that of the generator (the jointer). So It is my understanding that bonding the two systems would be required, making it easier IN MY OPINION to simply add a circuit from the house panel making a safe uncomplicated permanant instalation that is more "DIY" friendly.

Just my opinion I could be wrong after all I'm just some guy on the internet.

edited to ask

This sounds like a pretty industrial machine are you sure its 220v and not 208v? Did you actually check the nameplate?

JLMCDANIEL
Re: Running a 220v machine off a generator

You will need to make your own extension cord. I would suggest 12 ga.

The size of the breaker makes no difference, it protects the internal wiring of the generator, its purpose is not to protect the equipment connected to it. Even in the house wiring the breaker is sized to the in-wall wiring and not to the load that is going to be plugged in.

No ground electrode is needed because it is a closed system and does not use ground for a return.
Jack

canuk
Re: Running a 220v machine off a generator
ohmy wrote:

You can make an extension cord but the joiner will not have the proper protection because the genny breaker is a 30A. For your application we make a sub panel that plugs into the genny and then come off a the sub panel with the correct breaker.

Huh??
For the expense--- what benefit or need ?

Re: Running a 220v machine off a generator
JLMCDANIEL wrote:

No ground electrode is needed because it is a closed system and does not use ground for a return.
Jack

I disagree Jack. (no disrespect of course)

Its not temporary. Its no different then a standby system. Why wouldnt it require an electrode and bonding to the grounding electrode system? What excludes it from that requirement?

canuk
Re: Running a 220v machine off a generator

A portable generator needing an earth bond ?

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