Why Does My Angle Grinder Keep Tripping The Circuit Breaker?

Why does my angle grinder keep tripping the breaker?

Your angle grinder keeps tripping the breaker because of an armature shorting out or worn-out carbon brushes. A power cord that shorts out or a short outfield is another reason your angle grinder keeps tripping the breaker.


angle grinder tripping breaker


Short out armature

The only portion of the assembly that moves is the armature, a motor component you can find inside the field. Sometimes, the circuit breaker will trip due to an armature shorting out. To identify whether or not the armature is damaged will require removal, inspection, and testing.


Worn-out carbon brushes

Carbon brushes that have become worn out can trigger the circuit breaker to trip. Take off the lower cover so you can examine the level of wear on the carbon brushes. To remove the brush, you will first need to locate the brush holders and then slide the tension spring to the side.


Damaged power cord

The grinder receives its electricity from the outlet via the power cord. Conduct a thorough inspection of the cord to look for any abnormalities that could result in a short, such as cracks, splits, cuts, burn marks, etc. If you observe any of these, you should consider replacing the cord.

A cord that develops a short circuit can trigger the circuit breaker to trip. If the power cable appears in excellent shape, the problem may have been caused by something else causing it to trip the breaker.


Short-out field

The armature is within the field, which is an electromagnet that is located on the exterior of the motor. The field itself produces the magnetic field. The field has the potential to create a short, which will cause the circuit to trip.

Removing the gearbox assembly from the grinder is the first step in inspecting the field for any signs of burns, melting, or any other damage that could result in the power being interrupted or cut short.


How to fix an angle grinder that keeps tripping the breaker?

You can fix your angle grinder that keeps tripping the breaker by replacing the armature, replacing carbon brushes, and changing the power cord. Cleaning the fields is another fix for your angle grinder that keeps tripping the breaker.

Replacing the armature

If you realize your armature isn’t in good shape, replacing it will be the best option. Here are steps to follow to replace your armature.

  1. Take the gearbox assembly off the grinder.
  2. The brush holders can be removed by removing the lower cover and then letting the tension out of the springs holding them in place.
  3. Now, take the brushes out of the case. On certain models, there will be caps on the side that allow for the removal of the brushes easily.
  4. Take the armature out of the field and out of the grinder altogether. Utilizing electrical contact cleaner, thoroughly clean the armature.
  5. After it has been cleaned, check the armature for any burn marks, which indicate a short. If there are any signs of burning on the armature, it should be replaced.


The 180-degree test is one way to determine whether or not an armature is in working order. Once the armature has been removed from the device, place it upright on a table or bench. To determine the resistance of the windings, you will need to take an ohmmeter and attach its two ends to opposite sides of the commutator. It doesn’t matter what the reading number is as long as you keep moving it around the commutator.

You want to see a consistent reading indicating that all the windings are in good shape. The armature is defective if there is a significant amount of variation, with the reading either being zero or open circuit. If the ohmmeter shows a reading of zero, often known as an open circuit, this is evidence of a faulty armature.

The final test is called a bar-to-ground test, and it is performed by connecting one of the leads of the ohmmeter to the end of the shaft that the armature is attached.


Changing the power cord

Changing your power cord is another way to stop your angle grinder from tripping the breaker. Follow these steps to change your power cord.

  1. To change an electrical cord, you must first remove the lower cover or, depending on the model, the side cover from the grinder.
  2. Take the cable clamp off the cable.
  3. To begin, ensure that the connections on the switch where the power cord is hooked are properly secured and tight.
  4. If one has become disconnected, you should fix the wire end and reconnect it. If the cable needs to be replaced, detach it.
  5. Now, remove the insulation from the new cord (if it did not already come removed), twist the wire, crimp the new connectors onto the wire ends, and reattach the wires to the switch.
  6. Insert the switch into the housing, then use the clamp to keep the cable in place. Put back in place either the lower cover or the side cover.


Replacing carbon brushes

Your carbon brushes are important to the effectiveness of your angle grinder. You need to replace if damaged. There are steps you can follow to replace your carbon brushes.

  1. On some brands, the side cover must be removed first, followed by the paddle and the lock button.
  2. Take off the cover for the second side. Having found the brush holders, remove the tension spring by pulling it to the side, remove the electrical connector, and remove the brush.
  3. As the brushes wear out, replace them with ones that are 1/8 of an inch or less. Install it into the holder for the brush, and then relocate the spring to be on top of the brush.
  4. First, you should reattach the side cover, and then you should reconnect the electrical connection.
  5. Replace the lock button and the paddle, then close the device using the other side cover.
  6. There are additional models available that feature brush covers positioned on the grinder’s side for convenient access.
  7. Take these off with a screwdriver, then remove the brush from its slot. It is necessary to replace any brushes with a length of 1/8 of an inch or less.
  8. Replace the cap when you have reinstalled the new brush within the cap.


Cleaning the Field

Some models can remove the lower covers, paddle, and lock buttons. On other models, the lower covers are not removable. If you have one of the other models, removing the brushes will require you to first take off the brush caps on the grinder’s side. Follow these steps to clean your field.

  1. Remove the baffle plate and pull the armature away from the field as you do so. You can turn off the electricity by holding the switch in the OFF position and moving the switch lever to the forward position.
  2. After you have heard a click, you are free to take the button off the power supply. Disconnect the wire connections, keeping track of where each attaches so you can reassemble everything correctly.
  3. Take out the field from inside the housing for the grinder. Because the field could be very securely fastened, you might need to dangle the housing from the table to release it.
  4. Apply electrical contact cleaner to the field, and after that, examine the field for any signs of burn marks, indicating that it is shorting out. If there are burn scars on the field, you will likely need to replace them.

Using a multimeter, you may carry out a straightforward field test to determine whether there is a problem. The ohmmeter should be selected on the multimeter, and a lead should be positioned at each end of the field. If the reading is infinity, the field is defective and has to be replaced.


Why does my angle grinder keep tripping the GFCI?

The reason your angle grinder keeps tripping the GFCI is that your GFCI outlet has gone bad or there is an overloaded circuit. Worn-out insulation or an electrical wire deterioration is another reason your angle grinder keeps tripping the GFCI.

You will need to replace your GFCI to stop your angle grinder from tripping it. If replacing the outlet does not fix the problem, another outlet on the line may be faulty or something plugged into it. If this is the case, replacing the outlet may not be the solution. It’s also possible that the circuit breaker is faulty.

To determine whether the issue is with an appliance or an outlet, you should begin troubleshooting by unplugging everything plugged into all of the outlets on the same line. You may need to check each outlet on its own.


When checking electrical outlets, you should always exercise extreme caution. The issue may originate from an external source, such as water or an appliance; there may be an excessive number of items plugged in, which causes the circuit to become overloaded; the GFCI outlet may be defective, or the issue may lie further downstream on the same electrical line.

If you do not have the necessary experience, it is highly recommended that you seek the assistance of a skilled and experienced professional.


Why does my angle grinder keep blowing a fuse?

The reason your angle grinder keeps blowing a fuse is because of a short outfield coil or something is drawinh too much power from the circuit. A dirty armature or a wrong type of fuse is another reason your angle grinder keeps blowing a fuse.

If you have an older home or have been experiencing sporadic small electrical concerns (such as often tripped circuit breakers), then an electrical inspection would be a smart option for you to have done.

Be aware, however, that there are three distinct forms of electrical inspections: one performed by a qualified home inspector, one performed by a state inspector, and one performed by a licensed electrician. Each of these types of inspections serves a unique purpose.


Why does my Dewalt grinder keep blowing a fuse?

The reason your Dewalt grinder keeps blowing a fuse is because of brushes that are already worn out or a shorted armature. A dirty commutator or a bad outlet or plug is another reason your Dewalt grinder keeps blowing a fuse.

Use these methods to fix your Dewalt grinder.

  1. First, clean the com bars using sandpaper with a grit of 1000.
  2. Next, clean the grooves between the bars using a blade. After that, a toothbrush should be used to remove any residual carbon deposit from between the bars.
  3. Check the condition of the carbon brushes; if any of them are too short, contain chips, or are otherwise damaged, you should get a new set. In addition, check the communication bars to see if they are broken or out of place.


If none of those solutions work, you most likely have a short armature (sometimes field coils). To replace your armature, use the following steps.

  1. To determine whether or not the armature is intact, you must first visually examine it. An intact armature can be identified by the absence of a burnt spot on the wire coils or at the point where a wire is joined to the comm bars.
  2. You can proceed with additional investigation using a multimeter if you do not observe any charred spots. Check the resistance of each pair of adjacent comm bars using a multimeter with the low ohm setting.
  3. The numbers should be very close, and a more than 0.1 ohms difference is problematic.
  4. Next, take measurements of each pair 180 degrees from the other pair; the numbers must be relatively similar, and a significant gap indicates an issue.
  5. You also need to check if there is a short between the armature’s comm bars and its body and shaft. There must be no continuity.

If the armature successfully passes the test, the field coils are in the following stage. You have a pair of wire coils; check their resistance, and look for any burned spots on them. The level of their resistance must be extremely high, as before.


Why does my Makita grinder keep blowing a fuse?

The reason your Makita grinder keeps blowing a fuse is because of broken or worn carbon brushes or a broken armature.

The two components of an electric motor known as the carbon brushes are responsible for transferring current from the commutator to the revolving armature. A fuse may be blown if the carbon brushes are worn out or broken, as this will cause them to interact improperly with the communicator.

The carbon brushes may have been disconnected or worn down, which is the most likely cause of the sparks and/or smoke. For more steps, please refer to the guide for replacing the carbon brush.

  1. Using a Philips #02 screwdriver, unscrew the tapping screw with a 20 mm diameter.
  2. Pull the back cover down to expose the power cable.
  3. Put the springs holding the brushes in place to the side with the help of a spudger. One brush is on each side, making a total of two brushes.
  4. With the help of needle-nose pliers, carefully remove the carbon brushes by gently pulling on their crimped connectors.


Armature replacement

To replace your armature, follow these steps.

  1. Look around for the lock nut wrench that was provided. This is for removing the piece that is preventing the disk and cover from becoming detached from one another.
  2. Turn the screw to loosen the handle unit until it can be pulled out entirely.
  3. Keep your finger on the black switch on the front of the housing.
  4. While you continue to hold the switch in place, use the lock nut wrench to loosen the silver disk that keeps everything in its place.
  5. After becoming dislodged, take the silver disk and/or your grinding disk out of the machine.
  6. To remove the 15 mm pan head screw holding the cover, you will need a screwdriver with a Phillips #02 tip.
  7. To remove the cover, align the knob on the cover with the notch in the face plate, and then pull the cover off.
  8. Using a Philips #02 screwdriver, unscrew the tapping screw with a 20 mm diameter.
  9. Pull the back cover down to expose the power wire.
  10. Make a sideways adjustment to the brush holder coil by using a spudger.
  11. There are two brushes, each of which is held in place by a separate holder that can be found on either side of the object.
  12. Remove both carbon brushes (one on each side) using a metal spudger with their copper cabling. You should remove both carbon brushes.
  13. Remove the armature assembly by removing the four 20 mm tapping screws with a Phillips #2 screwdriver. These screws hold the armature assembly in place.
  14. Take the armature assembly out of the device.
  15. Using a Phillips #02 screwdriver, unscrew the faceplate by removing the four tapping screws measuring 10 millimeters in length that are holding it in place.
  16. Take off the front faceplate.
  17. Use a wrench of size 10 to hold the nut that is underlined. To unscrew, crank the armature counterclockwise while keeping the nut in place.
  18. It could be challenging to remove the nut.
  19. Take away the supporting armature.