(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 7 of 7

Thread: Wall Heater Wiring

  1. #1
    DIY Junior Member toolguy504's Avatar
    Join Date
    Dec 2007
    Location
    Chalmette, Louisiana
    Posts
    20

    Default Wall Heater Wiring

    I plan on installing wall heaters in two bathrooms. They have two kind that I am looking at. Heater (1) specs are 120 volt, 15 amps, 1800 watts with wire size 12 AWG. Heater (2) specs are 240 volt, 8.40 amps, 2000 watts with 14 AWG wire. Both heaters are the same price. I will be running 12 AWG wire regardless of which heater I use.
    What I would like to know is if I use the 240 volt heaters can I run them together on the same circuit? The distance from the panel box to the last heater is about 50 feet. I figure a 25 amp circuit with 12/2 wg should work. Or should I get the 120 volt heaters and just run 2 seperate 15 amp circuits to each. Thanks. Earl

  2. #2
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,374

    Default

    I know 12g is good for 20A, not sure about 25 or if you'd find 25A breakers. If you have room in the panel, I'd run 220 and control each from its own circuit. See what the pros have to say...
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  3. #3
    Homeowner Thatguy's Avatar
    Join Date
    Aug 2008
    Location
    MD
    Posts
    1,460

    Default

    Quote Originally Posted by toolguy504 View Post
    120 volt, 15 amps

    240 volt, 8.40 amps

    will be running 12 AWG wire regardless of which heater I use.
    The distance from the panel box to the last heater is about 50 feet.
    run them together or
    2 seperate 15 amp circuits to each.
    #12 fused at 15A?
    If the ampacity allows you to run them together the 15A heater should be closer to the panel. I doubt it does, but you're OK on voltage drop with #12 at this total current.
    Last edited by Thatguy; 08-10-2009 at 03:02 PM.

  4. #4
    DIY Junior Member toolguy504's Avatar
    Join Date
    Dec 2007
    Location
    Chalmette, Louisiana
    Posts
    20

    Default Wall Heater Wiring

    I'm sorry. I did not mean to say 2 seperate 15 amp circuits. I meant to say 2 seperate 20 amp circuits. Thanks. Earl

  5. #5
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,602

    Default wire

    If you use 25 amp breakers then switch to #10 wire. The size of the wires determines the breaker size, and #12 is only rated for 20 amps.

  6. #6
    Engineer Furd's Avatar
    Join Date
    Jul 2007
    Location
    Wet side of Washington State
    Posts
    446

    Default

    Using the criteria mentioned in the lead post the answer is no.

    The poster stated he would use 12-2 cable. The total current for two 240 volt, 8.4 ampere heaters would be 16.8 amperes. National Electrical Code states that fixed resistance space heating equipment branch circuits MUST be designed for 125% of the full load current which in this case would be 21 amperes. Number 12 wire is limited to a maximum of 20 amperes.

    In order to run both heaters on a single branch circuit the branch circuit would require a minimum ampacity of 21 amperes and that would require a minimum of number 10 conductors with a branch circuit overcurrent protective device (OCPD, i.e. fuse or circuit breaker) rated at either 25 or 30 amperes.

  7. #7
    DIY Junior Member toolguy504's Avatar
    Join Date
    Dec 2007
    Location
    Chalmette, Louisiana
    Posts
    20

    Default Wall Heater Wiring

    Thanks for the replys, especially from Furd. I think I will do as Jadnashua suggest and get the 240volt heaters and run each on it's own 20 amp circuit. Earl

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •