Class 120 refers to the temperature can withstand temperatures up to 120°C without degrading. Polyvinyl Acetal (PVA) is the insulating material used for the coating.
Insulating Material: The coating is based on a blend of polyvinyl acetal and phenolic resins.
Dimensions:
Film-Insulated Rectangular Magnet Wire Increase in Thickness and Width Due to Film Coating
| Build | Increase in Width | Increase in Thickness | ||||||
| Minimum | Maximum* | Minimum | Maximum* | |||||
| inches | mm | inches | mm | inches | mm | inches | mm | |
| Heavy | 0.0025 | 0.064 | 0.0045 | 0.114 | 0.0030 | 0.076 | 0.0050 | 0.127 |
| Quad | 0.0040 | 0.102 | 0.0060 | 0.152 | 0.0050 | 0.127 | 0.0070 | 0.178 |
Heavy and Quad Film-Insulated Square Magnet Wire Increase in Dimensions Due to Film Coating
| Square AWG Size | Radii (±25%) Nominal | Heavy | Quadruple | ||
| Minimum Increase | Maximum Overall | Minimum Increase | Maximum Overall | ||
| 1 | 1.00 | 0.080 | 7.549 | 0.127 | 7.600 |
| 2 | 1.00 | 0.080 | 6.736 | 0.127 | 6.787 |
| 3 | 1.00 | 0.080 | 6.012 | 0.127 | 6.063 |
| 4 | 1.00 | 0.080 | 5.367 | 0.127 | 5.418 |
| 5 | 1.00 | 0.080 | 4.793 | 0.127 | 4.844 |
| 6 | 0.80 | 0.080 | 4.282 | 0.127 | 4.333 |
| 7 | 0.80 | 0.080 | 3.828 | 0.127 | 3.879 |
| 8 | 0.80 | 0.080 | 3.424 | 0.127 | 3.475 |
| 9 | 0.67 | 0.080 | 3.061 | 0.127 | 3.112 |
| 10 | 0.67 | 0.080 | 2.741 | 0.127 | 2.791 |
| 11 | 0.50 | 0.080 | 2.456 | 0.127 | 2.507 |
| 12 | 0.50 | 0.080 | 2.205 | 0.127 | 2.256 |
| 13 | 0.40 | 0.080 | 1.981 | 0.127 | 2.032 |
| 14 | 0.40 | 0.080 | 1.781 | 0.127 | 1.831 |
Adherence And Flexibility: No cracks visible in the film coating after 15 percent elongation
Elongation: Not less than 32% for a thickness less than 1.25 mm and greater or 30 percent for a thickness less than 1.25 mm
Heat Shock: No cracks visible in the film coating after 10 percent elongation followed by conditioning at 175 ±3°C
Springback：Not greater than 5°
Dielectric Breakdown:
| Film insulation | Minimum Breakdown Voltage | |
| Heavy | 1500 | 500 |
| Quadruple | 2500 | 900 |
Completeness Of Cure: No swelling or blistering visible in the film coating
Periodic Conformance Tests:
Thermoplastic Flow：Median not less than 180ºC
Solubility: Specimens immersed in xylene shall not soften sufficiently to expose the bare conductor
Dielectric Breakdown At Rated Temperature: Average not less than 75% of the value at room temperature, when tested on round wire
Transformer Oil Resistance: 18 AWG Heavy film insulated wire shall not average less than 5700 volts