electrical question

[randy41]

i have a small greenhouse that i use for starts. it's heated with a small electric heater that is fed by a 220 line. the plate on the heater says it draws 23 amps. it is connected to a 30 amp breaker at the box. the cable is 10/3 (i think).
could i tap off this line at the receptacle in the greenhouse and have a 110 receptacle in there? i don't care if it is up to code, i just want to know if it would work.

 

[ray66v]

It probably is not 10/3, it is probably 10/2, with the third wire being a bare ground wire.

It would be unlikely they would have run a neutral wire, which you would need to have 110 volts. Because, a 220 volt heater would not need it.

If they did for some reason run 10/3, which means there would be 4 wires in the cable, you could in theory, have 110 volts coming off of that.

 

[randy41]

the "they" is me and i will check to see if its 10/3 or 10/2.

 

[kennyd]

So this greenhouse has it's own breaker panel?

Technically-you could get the 120v from the 240v heater line, but not only is it against code it very unsafe.

 

[deepNdirt]

How long use of wire and size wire is important to the green house? it would be best you used a small 30/40/50 amp panel box and and split from there using a 15 amp breaker for the 110/115v circuit, or if you know enough about what your doing you could use a disconnect box to split from,

 

[MikeD74T]

Randy, YES it will work, NO it's not to code nor particularly safe. MikeD74T

 

[LD1]

I would net do it even if it is 10/3. But yes it "can" be done.

Problem being that the 10/3 wire is rated for 30A and you are protecting it with a 30A breaker. It is "in theory" possible if you pull a 110 leg off, that you could be running more than 30A on the one leg and still the 23 on the other and the breaker NOT trip. It depends on the type of breaker though. I think most of them will trip if either leg sees more than 30A. But I have seen DIY jobs before where TWO 110 breakers were used and NOT pinned together. (that is what the little hole in the switch is for).

 

[Iplayfarmer]

How long use of wire and size wire is important to the green house? it would be best you used a small 30/40/50 amp panel box and and split from there using a 15 amp breaker for the 110/115v circuit, or if you know enough about what your doing you could use a disconnect box to split from,

This is the idea I like best. Basically you'd be installing a subpanel in your greenhouse. Run one double breaker for the heater and a 15 or 20 amp single breaker for the 110 volt outlet.

I have no idea about the code, but I can't see how this would be unsafe as long as the following conditions are met...

-The breaker in the main panel is sized to protect your wire (I.e. a 50 foot run of 10 awg needs a 30 amp or smaller breaker. See this calculator)

-Your sub panel is properly grounded.

-Your wiring within the greenhouse is up to snuff.

I'm happy to be educated otherwise if there are some specific safety concerns to wiring a subpanel in the greenhouse.

 

[Transit]

If you have lights than you have 110-120 volts. As for code, if any thing ever goes wrong kiss your fire insurance by-by.

 

[Craig Clayton]

This is Canadian Electrical advise, assuming the greenhouse is close to you main panel /house because I did not gather that your 240 V feeder was a long run simply pull in a new 120 V 15amp 14/2 feeder and mount your receptacle on the wall. I presume it will have to be a under ground installation so bury as per code with NMW in 1" poly at 15" min. but deeper is always safer and not against the code.
I know how to do it with a transformer but I am not going there.
Craig Clayton