The most common type of electrical outlet is a 3-prong outlet, which has two flat blades (one is wider than the other) and a round grounding pin. Older homes typically have 2-prong outlets that aren’t as safe as more modern options and are generally not up to current electrical codes.  Other outlets you can find in your home include 20A, 125 volt varieties for larger appliances like refrigerators or washing machines. 

There are also GFCI outlets, which protect against electrical shock in wet areas, such as bathrooms and kitchens, and arc fault circuit interrupter (AFCI) outlets, which protect against electrical fires caused by arcing.

Electrical fires are unique from other fire types because they have the potential to deliver electric shocks in addition to being on fire. Avoid serious injury from possible electrical emergency situations by avoiding the use of water, foam-based fire extinguishers, wet-chemical fire extinguishers,  flour, or baking powder to put out an electrical fire. 

It can be safe to buy or live in a house with knob and tube (K&T) wiring, but only if the system is in good condition, functional, and has been thoroughly inspected and approved by a licensed electrician. Never purchase a home with K&T wiring without getting a professional electrical inspection first.

Key considerations include:

• Safety and Condition: An inspector will verify that the wiring is safe and has not deteriorated. Over time, the insulation can wear away, leaving exposed wires that pose a significant fire or shock hazard.

• System Capacity: The electrical service should be at least 60 amps. However, even at this capacity, K&T systems often struggle to handle the demands of modern appliances and electronics.

• Lack of Grounding: Knob and tube wiring is an ungrounded system, which is a safety concern for many modern devices.

• Ongoing Maintenance: If you live in a home with K&T wiring, it's recommended to have it inspected by an electrician every one to two years to ensure it remains in safe working order.

Ultimately, any inspection or modification of a knob and tube system should always be performed by a certified professional.

The standard voltage for United States power outlets isn’t shared around the world, and neither is the shape of the power connector. This is why you need travel adapters when spending time abroad. Where the United States typically uses 110/120V outlets, outlets in Europe typically use 220/240V. Power outlets can vary in other ways around the world, too. Not everyone uses the 60Hz frequency, for example, and not everyone even uses AC power in outlets. Always do your research when traveling to see what you need.