However typically electric furnaces require a draw between 60 and 80 amps.
Electric furnace circuit breaker size.
Suppose a 12 gauge wire is used for 20 amperes lighting circuit having 120v single phase supply.
The electrical furnace is a very high power appliance 8 10kw at the minimum and it should be on a 3 wire 120 240 volts single phase service which has two live wires to increase its current capacity.
Let see the following solved examples.
The size of a breaker is determined by the amp draw.
These 3 heaters would require 12 2 wire and a 20 amp 2 pole breaker if they were to all be placed on the same circuit.
Range wire size depends on breaker size the size of the electrical cable is measured by its american wire gauge awg a system where the gauge number decreases with increasing wire diameter.
Multiply the value for current by 125 percent to determine the size of the breaker you need for the heater.
Maximum allowable wattage 80 of breaker max single phase breaker size wire size based on copper thhn wire increase one size when using aluminum conductors at 115 volts at 230 volts 15 amp 14 1 380 2 760 20 amp 12 1 840 3 680 30 amp 10 seldom used on 115 voltage 5 520.
Used when figuring electrical material needs and is already calculated in the chart.
A 1500 watt heater on a 120 volt circuit thus needs a breaker of 15 6 amps.
When placing multiple heaters on a circuit do not exceed the wattage listed for the corresponding wire and circuit breaker size.
So the double pole breaker is designed to trip and disconnect both live wires in the event of over current on either one of them.
Unit heater 10 kw 230v 3 phase find i wire size circuit breaker size conduit size i 10 kw 25 1 amp 23 kv 3 wire size 25 1a 31 3 amp 8 nec 310 16 use 8 good for 45 amp 3 8 1 8 ground in 1 rgc table 3a circuit breaker 25 1a 31 3 amp so use 35a 8 conduit size if different size wires are used.
2 1000w 1 1500w 240v heaters 3500 watts total.