How to Check 240 Voltage with a Multimeter (Guide)

Electricity running through your home is rated at 240 volts and is usually 220 volts. Heavily loaded electrical items such as refrigerators, dryers, and window unit air conditioners, use 220-volt electrical outlets to function properly.

In general, to check 240 Voltage with a multimeter you should  follow these steps:

  • Set your multimeter to 120 volts on the dial.
  • Find the circuit breaker for the 220v outlet
  • Switch on your multimeter and set it to measure voltage.
  • Connect your two test leads to the two slots on the outlet.
  • The black test lead should be connected to a neutral slot, and the red test lead should be connected to a hot space.

Let’s go through how to check the voltage with a multimeter. This will also assist you in detecting electrical circuit faults.

How to Test a 240 Volt Outlet with Multimeter

outlet test using multimeter

Set your multimeter to 120 volts on the dial. Insert the red probe’s metal tip into any slant 120-volt holes and the black probe’s metallic tip into the center (ground) slot. Your multimeter should register about 120 volts of alternating current (AC). If not, the circuit is faulty.

1. Remember, you will be doing this test on a live outlet

live outlet

Take precautions while completing it. You must make sure that you hold both of your multimeter probes in one hand at all times. This will protect you from being electrocuted. Never allow the metal components to become connected since this might result in a dangerous short circuit. Here’s how to find a short circuit with a multimeter.

2. Learn about your outlet’s area

It is vital to notice that an outlet has three slots. One is neutral, one is heated, and the third is ground. The neutral wire has a larger space on the left, and the hot wire has a short slot on the right. You can identify neutral wire with a multimeter, here’s how.

3. Make sure you locate the circuit breaker for the 220v outlet in the primary circuit panel.

outlet area

It is usually located in the utility room. Because your panel’s door is a label for your circuit breaker, the 220v outlet will likely have a maximum two-pole breaker.

4. Please turn on your multimeter’s power and preset it to measure voltage

After that, turn the multimeter’s switch knob to the AC side. Pick the approximate outlet and voltage check setting. The value you pick should preferably be between 220 and 240 VAC. Choose your alternating current in symbols (AC) to function on your meter. It is often represented by a wave line, whereas a dashed and solid line represents direct current in the symbols (DC) function.

5. Connect your two testers to your multimeter

multimeter outlet

Insert the black cable into the negative blackjack, which has a minus sign. The red line will be put into a positive blackjack, with a plus sign. These jacks are color-coded for easy identification and to ensure proper connections.

6. Connect your two test leads to the outlet’s two slots

Your two slots will likely be slanted if you have a three-prong outlet. If you have a four-prong outlet, the well-known two hot slots will have two outer spaces that are vertical. Check voltage readout should be between 220-240 volts when adequately plugged in.

7. Connect the black test lead to a neutral slot, and the red test leads to a hot space.

warning signage

It also applies to 3 and 4 prolong outlets; impartial prolong outlets are commonly L-shaped. Read the reported value, which should be between 110 and 120 volts. Then, insert the red test line into the hot slot and the black test line into the neutral space. The displayed reading value must be between 110 and 120 volts. Remember to unplug your test leads from the outlet and turn off your multimeter when you’re finished.

120 Voltage vs. 240 Voltage

120 Voltage240 Voltage
A standard 120V outlet has a 120V wire, a neutral wire, and, ideally, a grounding wire
120V has a less severe risk of lethal electrocution. Even though 120 V is regarded as safer than 220 V, it can be hazardous.
Transformers used at 120 volts might be more costly. 120 volts is when the voltage drops when connecting to a high-power consumption device. The greater the number of users, the more significant the voltage drop. 
A 240V outlet comprises two 120V lines and one neutral wire

These plugs are intended for use with ovens, dryers, as well as other high-powered devices.


A 240-volt outlet is bigger, with two vertical holes, an “L”-shaped hole on top, and a half-circle bottom port.

How to Test 240 Voltage with a Multimeter on a Dryer Plug Outlet

testing outlet using a multimeter

  • It is essential to know how to measure 240 voltage with a multimeter. We’ll use our multimeter to voltage check a typical dryer plug outlet.
  • The test selectors range from 30 amps to 125 volts to 250 volts. The neutral wire is located on the plug’s side, and it is your neutral link. It is your ground or green wire, and there is a hot wire of 120 volts going to the right-side outlet. Another 120 volts go to the opposite side, and we are dealing with 240 volts
  • We have a red lead, which we connect to the bolt, and a black lead, which we plug into the standard port.
  • We’ll put our tips in the neutral slot on one side. If it reads 119.9 V, and the opposite side of our multimeter also reports 119.9 V, everything is testing just as it should.
  • If every hot lead is 120 volts, the total voltage of the hot tips is 240 volts, and we have measured 239 volts. So far, we’ve learned how to test 240 voltage with a multimeter in a dryer plug outlet.

Current Generated from 240 Voltage

current generated

The amount of electricity supplied by 240 volts is compared to the amount of current provided by the transformer/generator. It is essential to know how to test 240 volt outlets with a multimeter. The current might range from a few thousand amperes to millions of amperes. The 240 volt supply at home can produce 0.1 million amps of current. (1)

Plug Contains 240 Volts

ground and neutral wires

A 240-volt power outlet typically features three openings. Two identical slots are angled at 45 degrees vertical and one center space lower than the two vertical spaces. Each vertical line carries 120 volts, while the middle space connects to the ground. (2)






References
(1) generator – https://www.britannica.com/technology/electric-generator
(2) vertical spaces – https://www.apartmenttherapy.com/design-tricks-to-make-the-most-of-vertical-space-263751

About Sam Orlovsky

b1d87d2ee85af3e51479df87928bdc88?s=90&d=mm&r=gI realized early on carpentry was a huge passion for me and I’ve stayed in the industry for over 20 years now. This gives me a unique ability to really be able to tell you what the best tools and recommendations are. I’m not only a carpenter but I also like machinery and anything to do with electrics. One of my career paths starting off was as an apprentice electrician so I also have a lot of experience with electrical products and anything related.