Is there a grounding wire in the cable that connects to the receptacle and goes all the way back to the grounding bar in the panel?

Yes, there is a grouding wire.

I bought a outlet tester to test wall outlet and the result shows correct wiring.

"It is definitely NOT those static shock, but a much stronger real 110v electrical shock." - that is not a very scientific way to tell anything. As an electrician, I have often touched live 110 wires with my finger tips and hardly feel anything at all. I get a much bigger jolt when someone touches me with static electricity. If someone touches the microwave and gets shocked, but can't immediately repeat being shocked, then it is most likely static electricity. If it is a momentary shock, and doesn't continue to tingle as long as you don't let go of the door, then it is most likely static electricity. Since the microwave is grounded, the breaker should be tripping if the electricity was coming from the microwave.

I agree with Fred. However, if there is any possibility that this is really electricity, you need to get this checked out by an electrician, as this would be a potentially lethal situation.

What do you professionals think about the following solution? Get a 3-prong plug and wire a single conductor wire to the ground terminal. Connect the other end of that wire to the case of the microwave, and insert the plug into an unused GROUNDED outlet. If there's a short inside the appliance, then the breaker will trip when the microwave is turned on or moved or whatever is done which causes the short.

(1) There already is a 3-prong plug with the other end of that wire connected to the case of the microwave.

(2) The grounding conductor must be run with the current carrying conductors.

250.4

(A) Grounded Systems

(1) Electrical System Grounding. Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

FPN: An important consideration for limiting the imposed voltage is the routing of bonding and grounding conductors so that they are not any longer than necessary to complete the connection without disturbing the permanent parts of the installation and so that unnecessary bends and loops are avoided.

(2) Grounding of Electrical Equipment. Normally non– current-carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected to earth so as to limit the voltage to ground on these materials.

(3) Bonding of Electrical Equipment. Normally non– current-carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected together and to the electrical supply source in a manner that establishes an effective groundfault current path.

(4) Bonding of Electrically Conductive Materials and Other Equipment. Normally non–current-carrying electrically conductive materials that are likely to become energized shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path.

(5) Effective Ground-Fault Current Path. Electrical equipment and wiring and other electrically conductive material likely to become energized shall be installed in a manner that creates a low-impedance circuit facilitating the operation of the overcurrent device or ground detector for high-impedance grounded systems. It shall be capable of safely carrying the maximum ground-fault current likely to be imposed on it from any point on the wiring system where a ground fault may occur to the electrical supply source. The earth shall not be considered as an effective ground-fault current path.

http://freenec.com/T72.html

250.114 Equipment Connected by Cord and Plug.

Under any of the conditions described in 250.114(1) through (4), exposed non–current-carrying metal parts of cord-and plug-connected equipment likely to become energized shall be connected to the equipment grounding conductor.

250.118 Types of Equipment Grounding Conductors.

The equipment grounding conductor run with or enclosing the circuit conductors shall be one or more or a combination of the following:

...

I was just suggesting this as a way to diagnose the problem, not as a permanent solution.

Various possibities, we can only guess.

Static, short internally, short at the strain relief, short on the cord. Maybe metal box for the outlet and something shorted in there. Have fun with your goose chase.

But, it already IS grounded. To diagnose THAT problem, you either check to make sure the terminals connecting the microwave to the cord are secure, and check that you have 110v to the ground at that point, or continuity of the cord. The other way to do the same thing as you suggest, if you are not hooking it up permanent, is to use a voltage tester from the hot side of a receptacle (the second one on the same yolk/circuit the micro is plugged into) to the metal parts of the microwave that are supposedly shocking you. If it reads 110-120v, then it is grounded properly, and could not have any more voltage than a neutral.

If it truly is still shocking you after that test, then the breaker should already be tripping, or your WHOLE neutral, grounding, bonding system is messed up for the entire house, and has nothing to do with the microwave. The grounding electrode system could have failed (ground rods are too dry, or loose grounding electrode conductor) or the neutral to the transformer is broken or loose....

You are right the breaker should trip if the hot is consistently exposed to the ground but what if it only shorts a tiny amount then arcs and moves. Would that be enough to trip the breaker? Considering an arc is a tiny explosion it should have enough power to move a small loose wire inside the unit? Just throwing out ideas.

Have you attempted to try another outlet. If so, the next step I would perform is a current leakage test on the device. This requires a special meter which induces a high voltage low current on the microwave. This test is for the insulation resistance of the microwave electrical wiring.

I was shocked again by Trim frame yesterday, two forearms shaking quickly during the shock, and a little sweating after the shock, not the static kind of shock.

Does anybody here seriously believe that a responsible parent would actually leave something as described by the OP plugged in??? Either it isn't grounded properly, or the op is seriously exaggerating. The ground doesn't just mysteriously disconnect every time the metal frame mysteriously gets energized. They are two separate connections with no physical means to choreograph them in such a manner. The breaker would trip with anything remotely close to that last description.

If this helps get you to call an electrician, what they are saying you don't have a ground working and full electric charge is going through you to find the ground. You can get shocked at dangerous levels.

First I am not sure this if this is a hoax. Since I would never leave the unit plugged in. Second it appears most of the responders are not aware of a requirement to perform an electrical resistance test. You can find information on YouTube on the topic. If you want to take the time you can also Google soldiers electrocuted in the shower in Iraq. The situation there was the contractor failed to establish a good earth ground prior to establishing a shower point. This is the reason today they include a current leakage tester. This meter is unique and there is a high probability the average electrician will not have this meter to perform the test. Ask before you pay for a visit.

even with all the stuff Fred S says you can still get a tingle...why...it is known as POLARITY SENSITIVE appliances....make sure red to red black to black white to white to white

The situation Adam describes is not normal and would constitute a defect in the appliance.

FWIW, though, the "All American Five" AC-DC tube radios of 1930s - 1960s had no power transformers, and they grounded one side of the line cord to their metal chassis. The plugs weren't polarized, either.

If the plug were inserted into the receptacle so that the hot side of the line was connected to the chassis, all the user/owner had to do was accidentally contact one of the metal control shafts, or one of the screws holding the chassis into the case through the bottom. If the user were also touching something grounded, the result was a potentially fatal shock.

Can you imagine a product like that being manufactured today? The company's lawyers would have fits.

The OP probably won't read this, but one possible cause of the symptom he describes above is a fault in the building wiring, combined with another defective appliance or device.

If all or part of the equipment ground system isn't properly connected at the main panel, leakage current from another appliance or device elsewhere in the house can be present at another receptacle's grounding pin.

For example, if the refrigerator had a fracture in its defrost heater's outer jacket, the microwave would only be electrically hot when the fridge was defrosting and had enough water in the drip pan to contact the defrosting element.

Not exactly....Range (which is new) was emitting a small charge when touching microwave or any proven grounging in any part of home...once RED WITH Red, BLACK with Black Neutral with neutral shock problem gone.

The Range is a second one as the first one did the same thing by emitting a small charge when the Black and Red were not matched.

Not all ranges made by a manufacter can be all defective because of this.

4 years ago. He either fixed it or died in the attempt.

Adam, thanks for the comments. You're not wrong that when making connections, neutral always goes to neutral. However, the rest of what you've written isn't quite so clear cut. Red and black are both hot wires and are interchangeable when supplying power, though I agree that it's usually good practice to match the wire colors where it's practical to do so. But what do you do when you're working with conduit wiring in a commercial building, and you have blue and orange hot wires?

What you've written above, and the tone of it, suggests to me that you may have been misinformed by someone you've worked with.

I suggest further research into electrical fundamentals. It's not all about matching colors. If you're a licensed electrician, this might be a good time for some continuing education, too. Good luck.

yes they MAY BE INTERCHANGEABLE as a old coil top range with mechanical clock...however with sensitive electronics, diodes, triacs, and small computers involved with new appliances have all in order...GFis Arcflaults Color to color from breaker out or it may get expensive or tingly in the nerves...

as for orange and brown and yellow that is a twist where as the electrician must take extra steps...TEST BEFORE TOUCH...test all angles before passing on to customer with documents/pics to CYA.

Electronics are polarity sensitive...so are cheap electronics...the difference is the good electronics are built with extras so leakage to ground is eliminated.. cheap ones are not

Adam, you're making absolutely no sense. There's no "polarity" in AC. It has nothing to do with cheapness or otherwise. Nothing should leak to ground PERIOD. Anything that does is malfunctioning.

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no problem..not here to argue make you see it on paper... Electronics are a Series of AC/DC on a board.. resisters, capcitors, diodes, triacs, relays ...some parts work AC and Some work DC. Some are built right some are built cheap... go with all theories and replacements that You believe will work until a right one is found or the polarity lines happen to line up just right ...and i will keep doing what i know and have done for close to 35 years of working in the field with my ELECTRICAL AND ELETRONICS tickets and i will just change two wires around to stop Electrical leakege/feed back on cheaper Electronics on ranges and dryers (yes this happens with newer dryers as well).

"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge." -- Daniel J. Boorstin

"The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge" - Stephen Hawking

More than one person over history has been credited with this quote in one form or another...

David, that's somewhat ironic. Hawking never said it, though many attribute it to him. It is, in fact, hard traceable to Daniel Boorstin.

Mine does same but it is just a tingle. I had to touch it a few times to make sure I was not imagining it. Definitely a very minor shock. No big deal. Just reading the people that do know. I've been shocked several times severely

I'm no kid. I am 70 years old. It just surprised me and I really thought I was imagining it like I said earlier. This young man if he is being shot like a serious 110-volt shot he better get it checked immediately.

You have a ground fault. It's obvious that the thing is not connected to a GFCI (if it's mounted in a cabinet it probably isn't strictly required, only receptacles serving countertop or near the sink require them). If you check the cord and the receptacle and the integrity is good, then the microwave itself is damaged.