# Does wiring heat elements in parallel vs series at the same power affects the results?

I am designing an electric kiln just for fun and I found myself not knowing how to answer this scenarios.

The main constant is power. The final power must be the same in each case. My question is about the effects of differents approach in order to get the best result.

Previous info

• Coil: Kanthal A1
• Diameter: 1.3mm
• Resistance: 1.09Ω/m
• Resistivity at 1300°C: 1.508Ωmm2

First scenario: Single element (or series, should be the same keeping the equivalent resistance)

• Voltage: 220V
• Power: 3000W
• Circuit current: 13.33A
• N° of elements: 1
• Element resistance: 16.88Ω
• Equivalent resistance: 16.88Ω
• Element current: 13.33A
• Lenght of heating element: 14.853m
• Element surface area: 606.614cm2

Second scenario: Two elements in parallel

• Voltage: 220V
• Power: 3000W
• Element power: 1500W
• Circuit current: 13.33A
• N° of elements: 2
• Element resistance: 33.75Ω
• Equivalent resistance: 16.88Ω
• Element current: 6.67A
• Lenght of heating element: 29.706m
• Element surface area: 1213.228cm2

Both circuits have the same power. The parallel ones has to double each resistance in order to get half the total power. We can see that the distance of the resistance has doubled and the current halved. This gets us more area in each coil with less surface load, that would benefit the lifespan of the coil.

If isolation is good in each case the energy would stay inside the kiln independent of the length and current of each heating element as my understanding. The heat would keep rising until get to an equilibrium with the kiln or reach the desired temperature.

1. Is there a difference in the heating of the kiln? Maybe it heat faster because of the bigger surface of the heating element but at the cost of less current per distance (I don't know if this is a thing)

2. Does current has an effect in the maximum temperature of each element? (at same power)

3. Would be the same if there were 2 in series with half the resistance?

To me seems more beneficial to use the parallel one if everything its the same and it would extend the lifespan of the coils because of the lower surface load.

Thermodynamics is not my forte. Correct me if my assumptions are incorrect.

--- edit ---

• Interior size 30x30x30cm
• Insulation is made with K23 fire bricks and an additional ceramic cloth outside
• I am planning on using PID controller with two relays in the parallel scenario that would control the duty cycle
• From reading you question I get the impession that you think that two parallel elements will give half the power of one. It won't. It will give twice the power of one. Series connection will give twice the resistance, half the current and 1/4 the power (since $P = I^2R$. Can you clarify? Commented Nov 5, 2022 at 15:07
• In order to keep the same power output each element in parallel will have 2 times the original resistance in order to get to 1500Watts each. These scenarios are changing the resistance in order to keep the output power the same. Commented Nov 5, 2022 at 16:09
• "In order to keep the same power output each element in parallel will have 2 times the original resistance in order to get to 1500Watts each." Correct. Commented Nov 5, 2022 at 17:00
• Don't use Kanthal; ( iron base) it becomes very brittle and weak after it is used. Use Nichrome ( Ni base), several very similar alloys. There are service ratings for permissible power density, like watts / square mm; Commented Nov 7, 2022 at 21:56