Generator adaptor

[Rick Peek]

I wondering if it is possible to make an adaptor cord for my generator
that would plug directly into the 30 amp 220 outlet in my garage?
(its my outlet for the dust collector) I was thinking that if I plug
into the 220 outlet on the generator & feed it thru the 30 amp
220 line to my breakers I could run alot of my house in the event
of a blackout. ( of course I would shut off the main breaker)
The generator has a 4 spade roloc,but my dust collector uses
a 30 amp roloc. Any help would be appreciated.

[Joe Mioux]

yes it can be done, but not recommended.

A better way is to install a transfer switch.

[Rick Peek]

Could you elaborate? I really don't want to drop a grand for something
I use maybe once every 2 years.

[Joe Mioux]

Over at my greenhouses, I have a transfer switch. The switch, when in the up position continues the circuit from the service side to the Breaker box.

When the switch is thrown down - taken off municipal electric, it can then be hooked up to my generate. On the bottom side of the switch there is a long heavy gauged wire "extension cord" with a plug on the end.

That plug gets plugged into the generator. The only thing I have to do is throw the breakers that aren't necessary so the generator can power the boiler pumps, fans, etc.

If I wanted to get fancier I could install a sub panel that would only feed the motors and equipment necessary.

I need to do this at my house also, but haven't gotten around to it. For you home you can get it done for around @ $200. That is what I was quoted a couple years ago from my electrical supplyhouse guy.

[David Christopher]

Rick, you dont need a transfer switch. just make sure that you dont back feed back to the power co. when we have hurricanes I pull the meter and back feed to my house from my welding machine outlet in my shop

[Mike Cruz]

Rick, here is the issue. YES, you CAN do it the way that you are proposing. HOWEVER, if you either forget to hit the breaker, or do it out of sequence, or someone else flips it to test if power is back on...WHATEVER... you will be feeding electricity back through the line exiting you house. The problem? When the local guy is working on your local power line to fix your outtage, if you are backfeeding power up the line, you could seriously injure or kill the guy. Yes, they are supposed to check to make sure power isn't getting reverse fed through the line before working on it, but we're all supposed to use dust masks, heaing protection, and eye protection in our shops, too.

What you are proposing is NOT to code, and for a reason. It is a risky way scenario.

[David G Baker]

Rick,
HD has a 60 amp transfer switch for around $130 or less. You will have to add some breakers but they aren't that expensive, the box comes with the 60 amp transfer breaker.
A lot of folks do the back feeding but if you are like me and make some errors once in a while the back feed error can easily kill.

[Scott T Smith]

Rick - lots of good feedback thus farm. Mike Cruz's comments - as usual - are right on target.

If you go the route outlined in your original post, you will need to upgrade the circuit to your dust collector outlet to include both a ground and a neutral, as well as the two load wires. At present, in all liklihood you lack a neutral at that outlet.

Also, you did not state what size generator that you have but presuming that it is around 6KW or less, simply run a new wire and upgrade your DC plug and receptacle to match what your generator uses (making sure that it is adequate amperage)

Now, if you want to meet code... read on.

Transfer switches come in two versions - manual and automatic, with manual being the least expensive. Transfer switches have to be sized based upon the largest load - which is usually the incoming line from the utility company and not your generator. Thus, a whole house transfer switch would typically need to be rated at 200A (if that's the size service that you have), even if you will only be using a 5KW generator.

The most economical approach - that will meet code - is to separate your critical circuits onto a subpanel, and then install a transfer switch for the subpanel. That way you can use a 30A transfer switch to match up with a 5KW generator. The 30A transfer switch cost a lot less than a 200A whole house version.

[Bill Brady]

Plugging into an existing 220v outlet is not a good idea as stated there is a real safety issue and you could damage the appliances in your house or the generator if both are on at once.

You can purchase an interlock device for between two breakers so they can not be on at the same time, all manufactureres make them. If you use one of these you can go the sub panel route and the cost is a lot less than a service transfer switch. The cost of an inlet to plug into and the breakers and interlock is less than $200.

[Robert Reece]

I have a real problem with the "back feed might kill somebody up the line" argument. If I attempted to backfeed my neighborhood with my 6kW generator- I suspect my generator breaker would pop. Every light and refrigerator would come on and the generator breaker would trip.

Yes, no?

Now, I can understand that when the power comes back on, if your generator is connected to that power, it might not survive. So when disconnecting the generator, you probably have to be careful that you don't "backfeed" your generator from the pole.

[JohnT Fitzgerald]

Robert - yes, you might have something 'pop'. but if someone is working on a line at the moment you fire it up, and all that current would need to go somewhere for your breaker to 'pop', it might just go through that worker and not your neighbors' appliances....

[Michael Wetzel]

I have a real problem with the "back feed might kill somebody up the line" argument. If I attempted to backfeed my neighborhood with my 6kW generator- I suspect my generator breaker would pop. Every light and refrigerator would come on and the generator breaker would trip.

If it can't happen, why is it against code and illegal to do? Backfeeding power is not an acceptable practice.


Have you ever worked in a service or 3phase environment? You learn very quickly to CYA on everything you touch. Backfeeding power is an unknown variable that can kick in anytime Bubba the hack decides to start the generator.

[Mike Cruz]

My neighbor, an electrician who has advised my on this very subject, told me that when you feed power back up the line, it actually increases at the transformers. So, your 5 kw generator creates a LOT more electricity.

I don't know all the ins and outs of how this works, but it made sense when explained to me.

[Rod Sheridan]

My neighbor, an electrician who has advised my on this very subject, told me that when you feed power back up the line, it actually increases at the transformers. So, your 5 kw generator creates a LOT more electricity.

I don't know all the ins and outs of how this works, but it made sense when explained to me.

Hi Mike, the voltage increases at the transformer, so a lineman working on the line would be subjected to the rated high voltage if the generator could carry the load.

Back feeding is illegal and can be fatal........Regards, Rod.

[Mike Cruz]

Yup, that sounds like what he said...