May 2025
By: Matt Hilbig (Master Electrician) & Josh Walejewski
Read Time: 1-2 Minutes

A Quick Walk‑Through of the Electrical Problem with Outlet Adapters

Pop into any hardware aisle and you’ll see them—little orange, yellow, or grey cubes that promise to make a two-slot outlet accept a three-prong plug. They cost pocket change and feel like an easy fix, but there’s a catch. These adapters typically come with zero instructions, so the one step that makes them ‘safe’ is often overlooked.

If you look closely at these adapters, they come with a metal tab (usually green) that must be screwed to a grounded outlet box. When that tab isn’t secured (or when the box behind the wall isn’t grounded to begin with), the adapter offers zero protection and can create a serious injury/shock hazard.

How Grounding Protects You

Modern appliances have that third-round prong for one reason—safety. If an appliance develops an internal fault, the grounding conductor gives stray current a low-resistance path straight to earth, tripping the breaker instead of traveling through you.

Two-slot outlets (installed in many Wisconsin homes built before the mid-1960s) don’t have that built-in path. The adapter tries to fake it with a small green metal tab that must be screwed to the outlet plate. If everything behind the wall is wired perfectly and the screw bites into a grounded metal box, the adapter should be adequately grounded. But all of these things have to line up:

1. The metal box behind the outlet is grounded.
2. The mounting screw is long enough to grab both the plate and the tab.
3. The person installing the adapter remembers to tighten the tab under the screw.

Miss any one of those, and the adapter is no safer than jamming a three-prong cord into a two-slot outlet with a butter knife (please don’t try that).

Understanding Exactly How Adapters Should be Installed:

A Real‑World Scenario

Picture a refrigerator plugged into an improperly installed two-prong adapter next to a stainless‑steel sink. A hidden wiring fault energizes the fridge’s metal case. You reach for a glass of water, one hand on the cold faucet, the other on the fridge handle—and you become the shortest path to ground.

This can cause serious injury or worse. The same risk exists for electronic appliances such as microwaves, washers, dryers, space heaters, and gaming computers running full tilt in the basement.

Difference

How to Tell If Your Outlets Are Grounded

Quick Check	What It Tells You
Metal box + armored (“BX”) cable	May be grounded but needs confirmation with test equipment.
Plastic box or cloth-covered wiring	Rarely grounded.

Pro Tip #1: Even if a voltage tester shows “grounded,” only a licensed electrician can verify that the ground path is continuous all the way back to your electrical panel.
Pro Tip #2: Never cut off or remove the round grounding prong to make a three-prong cord fit a two-slot outlet. Doing so greatly increases the risk of shock, fire, or electrocution. Replace the outlet with a grounded, three-slot receptacle instead.

Safe, Code-Compliant Fixes

Install GFCI outlets rated “GFCI protected, no equipment ground.” This brings two‑slot locations up to code and adds shock protection.
Upgrade branch circuits with new three-wire cable, metal boxes, and properly grounded receptacles. This is the best long-term solution for kitchens, baths, laundry areas, and garages.
Whole‑house rewire when you’re already remodeling. Yes, it’s an investment—but so is every device you want to keep safe. A whole-house rewire also helps future proofs your home for future renovations and upgrades.

Why DIY Isn’t the Answer Here

Even skilled homeowners run into hidden junction boxes, brittle cloth insulation, and mixed‑metal wiring that corrodes over time. An electrician carries the right meters, bonding jumpers, and—most important—knows the latest National Electrical Code updates adopted in Wisconsin.

Quick Safety Checklist to Share with Friends & Family

Look for two‑slot outlets in rooms with water (kitchens, baths, laundry). These areas should always be fitted with GFCI protected outlets.
Replace worn or cracked adapters immediately; never “daisy‑chain” them.
Unplug space heaters when not in use; they draw high current on older wiring.
Schedule a pro inspection if your home was built before 1970 or still has a mix of two‑ and three-slot outlets.

Wrap‑Up

Those $3 adapters feel convenient, but they can leave your biggest appliances (and your loved ones) without the protection modern wiring provides. Take advantage of Electrical Safety Month to get the peace of mind that comes with properly grounded circuits—no more shortcuts needed.

Have questions? Contact Kettle Moraine Electric and Solar today!