The HRHA series offers an optional RTV silicone coating that extends the resistor’s 3,000 V_RMS dielectric strength to 4,000 V_RMS, thereby enabling its use in applications with higher dielectric strength requirements and voltage safety margins. The coating also helps protect the resistor against humidity and dust in harsh environments by sealing the resistor and preventing moisture and dust particles from entering. The coating is recommended in harsh environments even if the dielectric strength requirement does not exceed 3,000 V_RMS. The optional coating may be requested by selecting option “C” in the manufacturer’s part number, as shown here.