|
Fri, Feb 15, 08 at 23:36
| Here's a question that I am unclear on. I have an electric heat circuit (240 volt) in a house I recently bought. It is wired with 12 guage wire, and is on a 20 amp breaker. This is an original circuit & wiring, circa 1973 when the house was built. There are 3 heaters, different rooms, 2000 watt, 1500 watt, and 1000 watt. All 3 are on individual thermostats. Does this count as a fixed load, for the 80% rule ? (240 volts x 80% = 3840 watts), or is this ok since each one has a seperate thermostat, and it's unlikely that all 3 would be in operation simultaneously for several hours ? |
Follow-Up Postings:
|
- Posted by petey_racer (My Page) on Sat, Feb 16, 08 at 7:35
| Here is the technical answer: NEC 2005 In today's world this installation would not be legal. |
|
| " is this ok since each one has a seperate thermostat, and it's unlikely that all 3 would be in operation simultaneously for several hours ?" I guess that's for you to decide: By code you need a 30A #10 cc't for this load. |
|
- Posted by bus_driver (My Page) on Sat, Feb 16, 08 at 8:57
| 1971 NEC 424.3(b) "The size of branch-circuit conductors and overcurrent protective devices supplying fixed electric space heating equipment consisting of resistive elements --- shall be calculated on the basis of 125% of the total load---." |
|
| Thanks for the prompt follow ups. That's what I was thinking also, because of course there will be times when all 3 heaters are on. I have easy access underneath, and plenty of room in the 200 amp breaker box, I think the first project will be to put the 2000 watt heater on it's own 20 amp circuit. Thanks for the help ! |
Please Note: Only registered members are able to post messages to this forum. If you are a member, please log in. If you aren't yet a member, join now!
Return to the Electrical Wiring Forum
Instructions
- You must be a registered member and logged in to post messages on our forums.
- Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review the contents and make changes.
- After posting your message, you may need to refresh the forum page in order to see it.
- It is illegal to post copyrighted material without the owner's consent.
- HTML codes are allowed in the message field only.
- No advertising is allowed in any of the forums.
- If you would like to practice posting or uploading photos, please visit our Test forum.
- If you need assistance, please Contact Us and we will be happy to help.