Definition
The maximum voltage an insulating material can withstand before it breaks down and allows electrical current to pass through it. Insulation strength is typically expressed in volts per unit of thickness and determines the safe operating voltage range for wires, cables, and electrical components.
Plain English
How much electrical pressure the covering on a wire can handle before electricity starts leaking through it. Stronger insulation can hold back more voltage without failing.
Context Anchor
Seen in aircraft electrical system maintenance, especially when discussing wires, ignition leads, connectors, and other parts that must keep electricity contained.
Derivation
Insulation comes from the Latin insula meaning 'island' -- the idea is that the material isolates the conductor, keeping the electricity on its own 'island' and away from everything around it. Strength here means the material's ability to resist failure under electrical stress.
Why Pilots Care
Low insulation strength can cause arcing, short circuits, or electrical fires that lead to system failures in flight.
Intuition Check
Do not read strength as only physical toughness. Here, insulation strength means resistance to electrical breakthrough.
Example Sentence 1
The mechanic replaced the old ignition lead because age and engine heat had reduced its insulation strength.
Example Sentence 2
Degraded insulation strength in the power cables required replacement to prevent arcing.