Converting 240 circuit to 2 120 circuits

Discussion in 'Electrical Forum discussion & Blog' started by apparentgenius, Nov 7, 2009.

  1. apparentgenius

    apparentgenius New Member

    Messages:
    21
    Location:
    Oregon
    My wife and I just embarked on a new career. We purchased a small motel on the Oregon coast. The place was built in 1949. There is some original wiring, some add on.

    THe original room wiring (lights and recepticles) consisted of 6 20a circuits (fuses) feeding 17 rooms. I found the original panel in the garage. This was fine when there were no tv's microwaves, small fridges. When the panel was changed to breakers, they installed 30 amp breakers on 12 gauge feeds. I imagine it was because they were blowing fuses as they added the microwaves.

    Obviously I want to upgrade the electrical but need to conserve cash especially since I can't do the work myself. There is a 20a 240V circuts in each room feeding the baseboard heaters. The rooms are small, about 230 sq ft. Currently there is a 8ft baseboard in the bedroom and a 3ft in the bathroom.

    My idea is to speak with an electrician about changing this circuit to 2 120 v 20a circuits by adding a neutral run to each room. I would run a 1500 W electric fireplace type stove heater, a 500W baseboard on one circuit, on the other circuit, we would run the microwave, small dorm fridge,TV. That way the original wiring would only be used for lights and outlets as it was meant to be.

    Hopefully the third wires can be fed thru the existing conduit, therefore greatly reducing the costs over feeding each room with a new circuit. I know that heating with 120 is less efficient, but am hoping that this would be a good tradeoff.

    Advice?

    Thanks,

    glen
  2. Cass

    Cass Plumber

    Messages:
    5,980
    Location:
    Ohio
    Unless you are interested in collecting fire insurance you need to change the 30A breakers to 20A breakers now...

    #12 wire is good only with a Max. breaker size of 20A

    For all the rest you need to have an electrician come in to do the work...this is commercial and with peoples lives at stake the liability is to high for you do do the work...
  3. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
    Basically a 120 volt heater will not heat as well as a 240 volt heater.

    And being a motel, I assume you would turn off the heat when the rooms are not occupied?

    So the question is, if the heat if off for a long time, it is cold outside, a person takes the room, then turns on the 120 volt heat, will the room heat up quickly enough to satisfy the customer?

    If it did not and all 17 of your rooms had the same problem, that could be a BIG mess you would be in!

    Also it is a royal pain to run an additional wire in conduit which already has wires in it! (For even a few feet distance.) I imagine some of your conduit runs would be quite long?

    What I would suggest is doing just two "model rooms" for now...

    Do one room with a new circuit added for fridge/microwave and leave the 240 volt heating circuits and heaters as they are. Then do another room as you are thinking.

    Then go through one winter season. Ask the persons who occupy those rooms if the room/heating was OK. Then if there is a problem, you will not have made a costly mistake with all 17 rooms! Also you could see the cost difference between the two rooms.

    So far as keeping the room warm once the room has warmed up, a 120 volt heater can do this providing there is good enough insulation. Another option would be to replace the windows with double insulated Energy Star windows and beef up the insulation. This would also save on the heating costs.

    Also research the coldest it ever gets in that area historically. If this winter does not get that cold, factor that in!
  4. apparentgenius

    apparentgenius New Member

    Messages:
    21
    Location:
    Oregon
    Thanks. That makes sense. The rooms are essentially in blocks of 6, so I was thinking of experimenting with one section.

    The winters are fairly mild here so I think I may be allright with the 120. If not, it will be fairly easy to go back to 240

    Thanks,
    glen
  5. Alectrician

    Alectrician DIY Senior Member

    Messages:
    689

    1) You absolutely never know if this will work in a building this old. This is a try it and see if we can do it project.


    2) You wouldn't just add a wire, you would pull in new wiring. The cost of the wire isn't the issue, it's the labor involved.
  6. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    999
    Location:
    NY State, USA
    This is not at all true. A heater designed to work at 120v will heat at EXACTLY the same rate as one of equal watts designed to work at 240v.

    The main problem with this theory is that he would have to change all the heaters to 120v. That in itself would kill the whole idea price wise. (Maybe that is what you are talking about???)
    I would simply add a circuit or two to each room and a sub-panel to help serve them all.





    I don't know why you would say this, unless the conduit had quite a few wires and/or the run is VERY long as you said. If there is a run to each room with only 3 or 4 wires in a 3/4" conduit for instance it will be quite easy and a life saver as far as labor goes.
  7. Billy_Bob

    Billy_Bob In the Trades

    Messages:
    422
  8. burleymike

    burleymike New Member

    Messages:
    118
    Location:
    Idaho
    How about PTAC heat pumps that way you will also have A/C for that one week a year you need it. Heat pumps use a lot less current than resistance heaters. Sounds like you do need to upgrade each room though.
  9. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    999
    Location:
    NY State, USA
    Billy Bob, you should really try and find some accurate articles to link. Those are all fluff and misinformation.

    SURE, a larger 240v heater will heat quicker and more efficiently than a smaller 120v heater, but that is apples to oranges. A 240v heater of the same wattage is NO MORE efficient than one of the same wattage at 120v.

    Those articles are extremely misleading. :rolleyes:
  10. burleymike

    burleymike New Member

    Messages:
    118
    Location:
    Idaho
    The benefit with 240v is you can go with smaller wire gauge.
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