Voltage, wattage, amperage questions… baseboard heat

[quikrick]

Hi, in a state of confusion I need some advice…
I want to install baseboard heaters (240volt) in my home (winnipeg, MB. Canada) where I have box space for one double breaker to make my 220 feed.
I will be installing five 240volt baseboard units with a total output of 2800 watts combined.
I’ve been given several different answers on the total amperage and wiring needed.

Am I correct in thinking that five 240volt heaters with a combined output of 2800 watts will draw a little over 11 Amps? If so, can I use a double 15 breaker to get my feed?
I have been told (home depot) that I can use NMD90 14-2 wiring for this application, will this be safe, or should I beef it up to 12-2 NMD90 or BX?
I intend to run one feed out from the box and junction it to the individual rooms where the heaters will be installed.
Any advice or tips are more than welcome.

Thanks in advance,
Rick

[Unregistered-t.b.]

I hate to confuse you more but 2800 watts divided by 5 equals 560 watts. That’s roughly the heat from 5 light bulbs. A typical plug in space heater is 1300-1500 watts. Are you sure it’s not 2800 watts each? But if it is then 2800 divided by 208 equals about 13.5 amps. That’s a bit over the recommended constant load for a 15a circuit. I would use 12 gauge wire but I would use the 15A breakers. Breakers are rated for overload before they trip. BTW I use 208 for less than optimal conditions.

[homebild]

You need a double pole 20 amp circuit with 12-2 wire.

Here’s why:

Volts X Amps = Watts

At 220 volts and 2800 watts you will need 12.72 amps

22 x Amps = 2800
Amps = 2800/220
Amps = 12.72

But because electrical codes only allow circuits to be loaded to 80% of their maximum capacity, a 15 amp breaker can only be loaded to a maximum 80% or 12 amps total.

Your loads exceed maximum for 15 amps and 14-2 wire and you must go to a 20 amp breaker and 12-2 wire.

If you use 220volts instead of 240volts in the forumulations you get 11.66 amps which is acceptable for 14-2 15 amp circuit at 80%, but since this is borderline it is best to go to the 20 amp 12-2 configuration to not risk circuit overload.

[Unregistered-Tom]

the only constant in this formula is the resistance of the heater. the 2800 watt figure is probably based on a 240 volt application. thus the resistance would be approximately 20.5 ohms. if the voltage = 208 the power would only be approx 2110 watts drawing 10.2 amps.. it all depends on the voltage rating that the 2800 watts is based on..

I=V/R 220VOLT/20.5 OHMS = 10.7 AMPS
P=VI 220VOLTS X 10.7 AMPS = 2354 WATTS.

P=V(sq)/R 240 X 240 = 57600/20.5 = 2809 watts

hope i didnt get carried away here.. bottom line.. be safe use 12/2 and 20 amp breakers and your sure not to have a problem…

[Author]

Posts