Nickel-Chromium Heater Wire - Temperature Rise vs. Amps
Electric resistance vs. temperature rise for Nickel-Chromium electrical heater wire.
Nickel-Chromium electric resistance wires:
| SWG | Diameter | Nickel–chromium | |||
|---|---|---|---|---|---|
| (mm) | (in) | (ohm/m) | Current (A) to maintain temperature rise | ||
| 500 °C | 1000 °C | ||||
| 12 | 2.642 | 0.104 | 0.197 | 38 | 78 |
| 14 | 2.032 | 0.080 | 0.333 | 26 | 53 |
| 16 | 1.626 | 0.064 | 0.520 | 19 | 40 |
| 18 | 1.219 | 0.048 | 0.92 | 13 | 27 |
| 20 | 0.914 | 0.036 | 1.65 | 8.5 | 18 |
| 22 | 0.711 | 0.028 | 2.72 | 6.3 | 13 |
| 24 | 0.559 | 0.022 | 4.40 | 4.5 | 9.5 |
| 26 | 0.457 | 0.018 | 6.60 | 3.5 | 7.0 |
| 28 | 0.376 | 0.0148 | 9.7 | 2.7 | 5.5 |
| 30 | 0.315 | 0.0124 | 13.9 | 2.2 | 4.5 |
| 32 | 0.274 | 0.0108 | 18.3 | 1.9 | 3.5 |
| 34 | 0.234 | 0.0092 | 25.2 | 1.6 | 3.0 |
| 36 | 0.193 | 0.0076 | 37.0 | 1.3 | 2.3 |
| 38 | 0.152 | 0.0060 | 59.0 | 1.0 | 1.7 |
| 40 | 0.122 | 0.0048 | 92 | 0.8 | 1.4 |
| 42 | 0.102 | 0.0040 | 133 | 0.65 | 1.1 |
| 44 | 0.0813 | 0.0032 | 208 | ||
| 46 | 0.0610 | 0.0024 | 370 | ||
| 48 | 0.0406 | 0.0016 | 835 | ||
| 50 | 0.0254 | 0.0010 | 2130 | ||
- SWG - Imperial Standard Wire Gauge for sheet metal and wire
Example - Electric heater
Calculate the length of a nickel-chromium gauge 18 wire in an electric heater with power 2000 W, 230 V supply and max. wire temperature 500 oC.
The current required to produce 2000 W can be calculated with Ohm's law as
P = U I (1)
or
I = P / U (2)
= (2000 W) / (230V)
= 8.7 A
The max. current in the 18 gauge wire with max. temperature 500 oC is 13 A and the heat can be produced in a single wire.
The total resistance in the heating wire can with Ohm's law be calculated as
R = U / I (3)
= (230 V) / (8.7 A)
= 26.4 ohm
Since the resistance of the wire is 0.92 ohm/m the length of the wire can be calculated as
l = (26.4 ohm) / (0.92 ohm/m)
= 28.7 m
