110 outta 220

[kennyd]

Why can't he do as he suggested when he said "i could just rewire the line at the breaker box and then rerewire it when i want to use the space heater in march."?

Just rewire at the breaker box with a 110 breaker and change to a 110 receptacle. As long as the wire is of sufficient size to carry the amp load, I don't see the problem?

He could.

 

[VA_Joe]

Back in the days when I worked in the machine shop for a large Manufacturing Plant all of the small (under 16" swing) lathes were powered by 220 3 phase circuits.

Attached to each lathe's power disconnect was a small metal junction box with a screw in Edison base 20 amp glass fuse and a single outlet cover to provide 120v for illumination. OSHA inspected the plant regularly and the 120v taps were never an issue.

My Grandparents 220v electric range has 2 120v outlets... one is on a timer and the other outlet is powered all the time.

Just my observations

That's because it used to be okay to run a small amount of current on the ground of a range circuit to power the clock-timer, lights, and other small draw accessories. This practice was recently (10 - 15 years ago???) banned by the NEC. You now need to run a separate neutral wire (i.e. four wires vice three). The reason is that current through a wire induces voltage. If someone was to touch the range chassis while also touching some other grounded appliance they could receive a very mild shock. Most of the time this induced voltage would be so low as to not be dangerous (or even perceptable by human). The problem is that if by chance the clock-timer or some other accessory had a fault and drew too much current - there is a chance that the chassis ground could be high enough to be deadly.

I suggest making sure that you have a valid neutral (and ground) if you plan on tapping 120 volt off the existing circult.

My two cents.

VA_Joe

 

[randy41]

I need to look at what I have at the box...its been many years since I first hooked it up...but I'm pretty sure I have 3 wire w/ground going there now.

thanks for all the responses.

 

[Soundguy]

I assume this was also how the 120v cooling fans ran on old buzzboxes??

Soundguy

That's because it used to be okay to run a small amount of current on the ground of a range circuit to power the clock-timer, lights, and other small draw accessories. This practice was recently (10 - 15 years ago???) banned by the NEC. You now need to run a separate neutral wire (i.e. four wires vice three). The reason is that current through a wire induces voltage. If someone was to touch the range chassis while also touching some other grounded appliance they could receive a very mild shock. Most of the time this induced voltage would be so low as to not be dangerous (or even perceptable by human). The problem is that if by chance the clock-timer or some other accessory had a fault and drew too much current - there is a chance that the chassis ground could be high enough to be deadly.

I suggest making sure that you have a valid neutral (and ground) if you plan on tapping 120 volt off the existing circult.

My two cents.

VA_Joe

 

[midlf]

If the buzz box had a neutral then yes. If it had a ground, no. The only code exemption that used to exist where you could cheat a 120v load onto a ground was for electric ranges and electric dryers. Both of these are no longer allowed. Most likely the transformer on the buzz box has a centertap for the fan if the fan is 120. It would be easier for the mfr to use a 240v fan, but I'm not familiar with the old buzz box.

 

[randy41]

Well I finally got around to doing this this morning. It's in the 20's and windy out but it's in the 70's in the unheated greenhouse.
So I just replaced the 2 pole 30 amp breaker in the main box with a 20 amp single pole one. The wire turned out to be 2/10 w ground so that worked out fine. I also replaced the 220 receptacle in the greenhouse with a 110 one. A little screw turning and wire stripping (needed to wrap the wire around the receptacle screws) and now I can start my onions.
I was also pleasently surprised at how well the 220 receptacle has held up in a sometimes very damp location.