Connecting a 120V heating cable to a 240V circuit will

Connecting a 120V heating cable to a 240V circuit will

• A. Melt the cable
• B. Trip the breaker
• C. No effect
• D. Reduce resistance

Answer: (A)

Resistive heating elements rely on the applied voltage to determine how much heat they generate. A 120V heating cable is designed to operate at 120V; its resistance sets a safe amount of current and heat. When you connect it to a 240V circuit, the voltage is doubled, and the power it produces goes up by the square of that change (P = V^2 / R). That means heat output becomes four times higher than intended. The insulation and jacket aren’t rated for that extra heat, so they overheat and can melt. The circuit might trip or fuse as a protective measure, but the immediate risk is damage from excessive heat, making melting the cable the likely outcome.

Resistive heating elements rely on the applied voltage to determine how much heat they generate. A 120V heating cable is designed to operate at 120V; its resistance sets a safe amount of current and heat. When you connect it to a 240V circuit, the voltage is doubled, and the power it produces goes up by the square of that change (P = V^2 / R). That means heat output becomes four times higher than intended. The insulation and jacket aren’t rated for that extra heat, so they overheat and can melt. The circuit might trip or fuse as a protective measure, but the immediate risk is damage from excessive heat, making melting the cable the likely outcome.