Series heater connection

[BAHTAH]

Would it be a code violation to connect two electric 1500watt 120v baseboard heaters in series in order to use an existing 20amp 120v circuit? This would allow for a reduced wattage per foot along the heaters but spread heat more evenly along a single wall.

 

[bennie]

Re: Series heater connection

1500 watts, divided by 120 volts, equal 12.5 amps.

120 volts divided by 12.5 amps equals 9.6 Ohms.

9.6 Ohms times 2 equals 19.2 Ohms.

120 divided by 19.2 ohms equals 6.25 amps.

6.25 amps times 120 volts equals 750 watts.

You will cut the heat in half, and yes, spread it out. Not a good idea, but it will work if you like cold.

There can be some possible sections to quote for a violation, but not many people would elect to do this.

 

[charlie b]

Re: Series heater connection

Originally posted by bennie: . . . 750 watts. You will cut the heat in half . . . .

Actually, you will cut the heat to one quarter of its original value. You can get 3000 watts out of the two heaters, and now you will only get 750. So it is a real waste of equipment. You would be better off by installing only one heater ? at least you would get the full value of 1500 watts.

But you might also consider 110.3 (B) Installation and Use, ?Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.? I don?t think giving each heater 60 volts (i.e., half of its rated 120 volts) would fulfill the manufacturer?s requirements.

 

[BAHTAH]

Re: Series heater connection

Thanks for the input, I was kicking this idea around with a friend who has small rental units and we were trying to figure a good way to reduce the heat from baseboards on the walls where there are drapes. Looks like some lower density heaters would be the best solution. Thanks again.

 

[renosteinke]

Re: Series heater connection

UL will typically test electrical products to +10-15% of their rated voltage, but their testing is limited to testing "for safety," and typically focuses on whether the appliance overheats.
In your example, it would probably be OK ( the heaters get cooler, not hotter), but going in the opposite direction (paralleling units for more heat) would not.
More of an engineering question than a code question.