* Material: T-shirts are typically made from cotton, a natural fiber. Cotton is a poor conductor of electricity. This means it resists the flow of electric current.

* Structure: The woven structure of a t-shirt traps air, further increasing its insulating properties.

However, it's important to note:

* Moisture: If the t-shirt becomes wet, its insulating properties decrease significantly. Water is a good conductor of electricity.

* Specific Fabric: Certain t-shirts made from synthetic materials or with conductive threads could behave differently.

In general, it's best to avoid wearing a t-shirt when working with electricity. Always wear proper protective clothing and take safety precautions.