The phrase "an electrical insulator" is correct and usable in written English.
It can be used when referring to a material that does not conduct electricity, often in the context of electrical engineering or physics.
Example: "Rubber is commonly used as an electrical insulator in various applications to prevent accidental electric shocks."
Alternatives: "a non-conductive material" or "an insulating material".
Calling it the first plastic, Mr. Heite said vulcanized fiber, patented in 1859, found application as an electrical insulator when electric lighting was introduced.
The electro-optical fluid is an electrical insulator, so very little electric current flows.
It was a very important step as some tube clustering may occur under powder mixing and further formed Al-BNNT pellets cannot be electrically conductive (BNNT fraction is an electrical insulator).
The photoconductor, which is an electrical insulator in the absence of light but which conducts electricity when illuminated, is exposed to an image of the document to be copied.
Other materials can be an electrical insulator on the inside but a conductor on the surface.
Attached too tightly, as in an electrical insulator, the electrons cannot move freely; they are stuck.
Except for most natural blue diamonds, which are semiconductors due to substitutional boron impurities replacing carbon atoms, diamond is a good electrical insulator, having a resistivity of 100 GΩ·m to 1 EΩ·m (1011 to 1018 Ω·m).
It resists attack by most chemicals, is impermeable to gases, retains its properties upon exposure to gamma radiation, and is an excellent electrical insulator.
SF6 is a superb electrical insulator, and laboratories employed it not only to shield high-voltage lines and equipment, but also for uses like dampening sparks in certain experiments.
They are a good electrical insulator, lightweight, and some of them can be molded into very large complex shapes that would require many parts and assembly operations for other materials.
The team, at L'École Normale Supérieure in Paris, describes in today's issue of Science how they created an extremely tiny electrical insulator called a quantum dot, which allows electrons through to the 2DEG one at a time whenever it receives a tickle of electricity.
