Microwave leaks

I try to keep up to date with what is happening on the web with anything to do with microwave ovens. A very motive subject is that of microwave leakage. I think it is very important firstly to describe as briefly as possible what microwaves are and how they work. A micro wave is exactly that, a very small wave of energy that is produced. It is very similar to a radio or mobile phone signal (in fact the correct term for those waves used in microwave cooking are radio frequency or RF waves). Instead of being converted by a receiver into a sound it is emitted into the microwave oven cavity where it is absorbed by the molecules of moisture in the food which in turn causes them to vibrate against each other. The friction this creates make the food hot. Microwaves therefore are Non Ionising. This means that they are not radioactive, they are not nuclear and they have no after life. If you open the microwave door during cooking the oven will stop producing microwaves and those in the cavity will have dissapated by the time you put your hand in the oven to remove the food. Their energy will have been completely converted into heat within the food.

If a microwave oven does leak into the atmosphere it is still unlikely to cause any great issues. From where they are emitted (the magnetron) their power reduction is inversely proportional. The power reduces greatly as the distance increases, therefore even if they did leak into the kitchen they would not have the energy or power to cause any harm in the kitchen.

A common rumour is that standing in front of the microwave whilst using it will be harmful. This is incorrect. Microwave ovens have many safety aspects to prevent just this. Their design means that microwaves cant escape during cooking. You may notice that all microwave doors are at least a certain thickness. This is because the edge of the door has a ‘channel’ built into it into which any stray microwaves will get trapped. The thickness of this channel allows the microwaves to then ‘fold up’ on themselves time and time again until they dissapate. The door screen that you can look through has a fine metal mesh built into it. This allows you to look into the oven but the holes are small enough not to allow any microwaves through. Often, if you feel around the doorway during cooking you can feel an flow of air. This is common and is not a flow of microwaves. Normal microwave design allows the cooling fan to blow air over the ‘workings’ of the oven to cool them, then through the cavity to carry away any condensation. there are some vents but a lot of air blows around the door frame beacuse there is a gap around the frame. Again the gap is not big enough to allow microwaves through.  You will notice also that the oven has a metal outer cabinet. In the rare instances that a fault may occur inside the oven, any microwaves will bounce around underneath the cabinet antil they too dissapate. Occasionally this does happen and at worse those microwaves may damage the electronics on the control circuits. In our experience microwaves have never found an alternative exit from the oven.

rf leakage tester

As part of any microwave repair our engineers test the oven for any RF or microwave leakage. The test is quite easy but to be accurate we use a meter that is calibrated professionally on an annual basis.

Although we don’t find many problems with microwave leakage,  it is useful for peace of mind to know that it is operating correctly and safely. If there is a liability issue involved for instance if microwave ovens are used by employees at work then good practice would be to have them checked periodically. As a business we can carry out periodic testing and apply a sticker to the oven to indicate the date of its last test.


About microwaveexpert

The Microwave Service Company is based in Sellindge, Kent and provides repairs to Domestic and Commercial Microwave Ovens including 24 volt Samsung Roadmate microwaves.
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44 Responses to Microwave leaks

  1. Neil says:

    I have found some microwaves operating without internal waveguide (Metalised board) screens, does this present any Health & Safety issues?

    • There isnt a safety issue. The waveguide cover that you mention is there to caver the aperture through which microwaves pass to get into the oven cavity. The cover which is usually made of a material called Mica is invisible to microwaves so they pass through it easily. Because of the nature of mica it does soak up moisture and food debris and because of that degrades and eventaully falls to pieces. More often though if too much debris or moisture is absorbed it can then get hot hot and then start arcing or sparking. The cover doesnt need to be in place to operate properley but in the long term if the waveguide cover has failed due to debris and moisture there is the chabce that this could build up in the waveguide, which essentially is the workings of the oven. In the long term this would reduce the life of the microwave.
      In short, the oven will be safe but the oven will last longer and perform better if it is replaced.

      • Zach Barreto says:

        I am in need of someone familiar with MHC microwaves. I am looking for someone in the US familiar with the design or production of these microwaves and someone who can discuss quality controls. Let me know if this is something you would be interested in or if there is anyone that you would recommend that has the right qualifications. I can be reached at 646.216.2338.


        Zachary Barreto

  2. Jane O'Leary says:


    Back in 1980 or 1981, we bought a brand new microwave. A small plastic side piece (approx. 4″ panel?)next to the door came off when something hit it. It was a clean break, so my dad put duct tape (could have been electical tape or even masking) over the plastic bit to keep it on tight. I tried to find pictures of that old microwave, but couldn’t. It looked like a panel on the left side that bumped right up against the door, but wasn’t anything that was made to be accessed by a professional. Maybe decorative? The door itself seemed fine, but I’m not positive.

    I used it for about 10 years and have always worried about the microwave leakage that could have occurred with the duct tape solution. Should I be concerned about an early-model microwave with the plastic exterior duct-taped together?

    This is one of the weirdest questions I’ve ever asked, but I’m still concerned to this day.

    • Not at all weird. There was a lot of scaremongering going on in the early days of microwave ovens so there are a lot of misconceptions. In answer to your question, There was most unlikely any leakeage from your microwave oven. The design of the door hasnt changed a great deal over the years. Essentially, the inner part of the door which is the door frame and is made of metal (and contains the metal mesh you can see when you look into the oven) retains the microwaves in the oven cavity. The plastic trim and glass door screens are mainly for decoration although they help with making the oven easier to clean, preventing condensation buildup etc. These trim parts dont effect leakage in any way. I’m absolutely sure that will have suffered no ill effects from leakage.

  3. Hannah says:

    Ok. Curiosity has a hold of me. I went to my breakroom to heat something in one of the microwaves. I opened the door and placed my item on the turn table and noticed is was turning, then realized it was humming like it was on (I’m hearing impaired, so I normally don’t pay much attention to what sounds I DO hear). I quickly snatched my hand out and shut the door, then remembered my item was still in there. So I opened the door and retrieved it (as it was operating again) so I could use another microwave instead. After thinking about it for a second, I remembered being told that microwaves can be harmful to people, so I informed someone of the malfunction, and started doing research. Should I be worried about exposure to my hand/arm? It was in there a total of about 4 or 5 seconds.

    • Microwave ovens have very good safety interlocks. It may be that although the oven was turning and making a noise that it wasn’t actually operating. It would obviously be faulty and should be attended to. Microwaves would burn you but it would be in the same context as a conventional oven. if you left your hand in a normal oven for too long it would get hot and burn. The microwave is the same. If you were able to leave your hand in there for a long time whilst running (which you can’t generally) you would feel hot and then ultimately burn. Microwaves are really only harmful in that respect, there is no danger of any other long term effects that people associate with ionising radiation, so if your hand feels ok, then I’m sure it is ok.

      • Hannah says:

        My hand and arm are okay now, but that day, however, the skin on my hand and forearm did end up with a weird hot, tingling, and tight/dry sensation that eventually subsided over the next 24 hours. So I do believe it may have indeed have had a giltch in the safety interlock, as if it was somehow reversed. Needless to say, the microwave had already been removed from the breakroom when I went back 30 minutes later for a drink.

  4. Joseph says:

    My internet connection drops every time the microwave is running does it mean its leaking and interfering with the internet

    • Unfortunately it seems that your microwave may be leaking. Microwaves and Wi-fi routers operate on a very similar frequency so if the microwave is leaking it may well affect the internet. A Microwave oven doesn’t need to be completely leak free to be safe to us but a very minor leakage could affect the wi-fi. Initially you should have your microwave checked. A competent microwave engineer would have a calibrated meter and would be able to tell you if your oven is leaking and by how much. if it is within the accepted tolerance ( a leakage of up to 5mw is considered acceptable) then you may have to move either the microwave or router so that they don’t affect each other. If the leakage is unacceptable then you may need a repair or to replace the oven.

  5. Peter Goddard says:


    I have a slightly faulty catch (I repaired it once but has gobe again) on my Siemens microwave, that means that when the door is shut, I can still push it in about a further 2mm.

    Could one have leakage through a 2mm gap parallel to the door?

    If so is there any reason why (to be sure?) one should not use a rubber wedge each time to push the door tightly home?

    • If the oven door had been loose from day one then I wouldn’t have been concerned as the door does not need to be airtight to stop microwaves and may have been adjusted that way. However, as you have repaired the oven I suspect that the latching may well be out of adjustment and although I wouldn’t expect a leak it is possible. I would suggest that you get an expert to look at the oven, either to repair it properly or at least to check for leakage with a calibrated test meter.

  6. I have an 1100 watt microwave and noticed that there is a lot of air that comes out from the bottom when turned on, almost as though the wind is blowing. Is that normal?

    • Yes it is. The oven is designed to draw cool air over the ‘workings’ to cool them down and then blow through the cavity to carry out any condensation.

  7. Jenni says:

    My microwave has a hole in the bottom. Is it still safe to use? Occasionally it will turn off half way thru poking. I assume that’s because of a safety feature. Advice?

    • If there is a hole in the bottom of the oven then no, it is not safe. It may be possible for microwaves to leak. The hole will not be repairable. You should consider replacing the oven as soon as possible.

  8. jc says:

    my microwave burned a hole in bottom I am not sure if it is all the way thro or not it broke the glass first. Is it safe to even have in my kitchen not in use , cn it leak radiation?

    • If there is a hole in the bottom of the oven then no, it is not safe to use. It may be possible for microwaves to leak during operation. The hole will not be repairable. You should consider replacing the oven as soon as possible.

  9. gareth says:

    We have a microwave with a foot long hole in the rear of the unit.. I can pass a teaspoon out of inside the microwave to the outside world. we only noticed when it started sparking ,, then spotted the hole. the rust looks old and no idea how long we have been using this in this state. is there any potential danger to health from this to us in your opinion ? the back was against a tiles wall.. could this have defected to microwaves. Not sure if legal action is required against the manufacturer if any potential fro health issues

    • It is unlikely that you have been harmed as microwaves dissipate very quickly over distance , however. You should stop using the oven and replace it. A rusted hole will be un-repairable.

  10. scorpion says:

    My microwave is built in as part of a conventional wall oven. Since a repair some time ago when it was disassembled, the door switch has been tempermental. A tech looked at it and said that the frame is bent and the door can’t close up tight enough to engage the switch. They sent yet another tech that got the switch to engage, but there is still a physical gap between the door ‘seal’ and the interior of the oven. On one side of the door, i can insert a dollar bill and slide it unobstructed from top to bottom
    a thermal scanner registers about 10-20 degrees hotter on this loose side of the door
    service company says it is fine. I am under a service contract, they are obligated to replace the appliance if it cannot be repaired, they have an incentive to declare it safe…

    • The fact that you can slide a bill down the side wouldn’t necessarily indicate a problem if it were just a microwave. The door doesn’t need to be airtight to stop microwaves escaping. The fact that hot air is escaping specifically from that side on convection suggests that heat is being wasted and is therefore not running efficiently. If the door is distorted enough to be noticeable then I would suggest that it ought to be changed. usually that would be down to the discretion of the customer, ie whether you would want to pay to have it repaired rather than accept that some heat may escape especially if you don’t use the oven part very often.

  11. Our over the oven microwave was taken out of the casing and repaired for a door latch issue originally. When they put it back in the casing they bent the side of the case so that it isn’t flush with the microwave. It bows out and you can see clearly through the holes that are built in the side of the microwave into the microwave. From your earlier descriptions I’m thinking that the microwave is still safe since the outside casing is not the actual microwave. Or is it? Is that outside black case supposed to be what keeps the microwaves inside? I have a picture but don’t see a way to insert it.

    • Hi Aurelia, Yes the oven is probably safe as it is the metal part of the door frame that retains the microwaves. It might be a good idea to get it checked for leakage for peace of mind. All microwave repairers should have a meter to check for leakage.

      • sarah says:

        We have a hole in the underneath of the left corner of the door. I tried glueing the piece but it fell out. Its about the size of the tip of my thumb. Is it safe to use.

      • If the piece that fell off is plastic then it wont cause any problems with microwave leakage as all of the plastic and glass are invisible to microwaves. The microwaves are retained in the oven by the metal part of the door frame. The only issue you may have is that cooling air that circulates the microwave may get between the door parts and cause a build up of condensation. If it does although it wont be dangerous it will cause rust in the long term.

  12. Ann Connor says:

    I have a small chip on the closing edge of the glass door on the front of the microwave. The plastic part of the edge of the door is totally undamaged. No damage to metal frame. I most likely hit it with a bowl as I was removing it from the oven causing this slight damage to the glass.mam I correct to think that this outer door glass is only cosmetic and that the microwave should not leak?

    • Correct. The microwaves are retained by the metal part of the door. The plastic trim and glass screen will not affect microwave leakage. If badly damaged the trim and glass may have an effect on the airflow through the oven but the small chip you mention shouldn’t affect this.

  13. jeannie tates says:

    My whirlpool microwave vip 27 blows air when opening the door is this normal

    • Yes. The oven is designed to blow cool air through the electrics to cool it then to pass through the oven cavity to carry away excess condensation. It is probably this air blowing out of the doorway as the fan slows down that you are experiencing. It is normal.

  14. RV says:

    Hi there, I have a question about Microwave radiation in general. It is known that the metal “cage” designed into the interior of the microwave oven stops the microwave radiation/RF leaking to the outside. It is also known that mobile/cell phone networks use microwaves for their comms at similar frequencies. Well, why does my mobile phone signal IMPROVE when I place it inside the microwave oven with the door shut! (with the oven off of coarse). One would assume that if the specially designed, microwave reflecting and trapping “cage” stops microwave energy from escaping, then it should also stop it from entering making my phone reception either decrease or drop off all together. I just tried my experiment for a second time just to be sure, and it went from 1 bar of signal outside of the oven to 3 bars inside the oven…….strange indeed.
    I would be interested to hear any thoughts on this subject. Just for curiosity.

    • A microwave oven doesn’t act as a Faraday cage. The doorway seals in a different way that is efficient enough to stop microwaves from escaping. It doesn’t necessarily stop mobile phone signals.
      Different types of network use different frequencies (3G, 4G) etc so different phones would behave differently in a microwave. One would expect the signal to be poorer But – It may be that your phone signal can get into the oven readily and in fact is being amplified by bouncing off the interior of the oven so that the phone reports a better than normal signal.

  15. Will Farquharson says:

    I have an integrated Siemens combo micro/oven that I just had repaired by an engineer.

    However, during his leakage test, his device beeped as it went over the corners of the door. He said he can’t certify it “leak free” as a result, and couldn’t really answer whether it was safe to use or not – just said it was my own choice.

    Is it advisable to still use it? What if I stood a certain distance away? The only thing he could offer to do was bring the whole thing back to his workshop, which could turn out to be quite costly for me, but at the same time, I don’t want my internal organs cooked!

    If you have any advice, I’d love to hear it! Thanks!!

    • Thank you for your enquiry. If the engineer doing the test was doing it correctly with a calibrated meter and he declared it leaking excessively then I would think that he considers it unsafe. The further away from the oven you stand the safer you will be certainly. But guidelines are put in place to give customers an assurance. A reading of more than 5 Milliwatts at 25mm from the surface of the oven is considered excessive (in UK) and requires attention. If you paid a qualified expert to offer his opinion then it would be wise to accept his recommendations.

  16. Shawn says:

    I can not seem to find an answer to this but I have an old sharp carousel I bought because it is only 400 watts. It works well but I noticed that next to the mica it has what looks like vent holes, these vent holes are covered with plastic. Should I peel that off or leave it on?

    • Those vent holes I suspect are the ‘mesh’ through which the oven light shines. It is a good idea to replace it if it is lifting off. Although not dangerous it does affect the long term life of the oven. The main reason for it being there is to stop food debris getting into the workings of the oven in particular onto the light bulb which will shorten the bulbs life – and make it more difficult to see whats going on inside your oven. The other reason is that by design the oven draws in air and circulates around to cool itself down. That cover is helping it to direct air and may prevent it from cooling correctly if not in place. So, dont remove it unless you can replace it.
      We do sell a large sheet of clear plastic that you can cut to shape on our website : inner door film website link

  17. Pris says:

    My husband heated a bowl of noodles for 3:45 and it was steaming hot. But when I did mine it only got warmed. He did another one after and it was’t as hot as his first bowl. I also felt the air vented from the side felt warm instead of the usual cool. Is something going wrong with my microwave?
    Thanks for your advice.

  18. Helen says:

    I have some friends who are blind and have a talking microwave. I noticed that it has rusted out a hole in the back of the microwave. Is there anyway to repair this because the do not have the $400 it would take to buy another talking microwave.

    • If it is a hole in the metal cavity of the oven then unfortunately it is unlikely to be easily repairable. It is possible to replace that cavity which essentially the chassis of the oven but it is a big job and most manufacturers dont supply the cavity as a spare part. if it were a make such as Panasonic or Sharp it might be worth getting in touch with the manufacture in your country (The manufacturers only deal with those models sold in the country of origin, so I cant find out whether parts for a US model are available through our Panasonic UK website for instance). if it is available then you will need to find a repairer who will take on a cavity change and try to find out whether it will be economical to do so.

  19. Erica says:

    I just noticed the screen inside the front door has separated from the door in the bottom left corner, it is as if the adhesive is gone and maybe even a bend at that corner. I tried to push it back but it gets condensation on glass door in the corner when in use. Is this dangerous and do I need to replace or is it fixable? Its a built in above our oven.

  20. Robin says:

    Using my microwave, I recently noticed steam escaping from the hinged side of the door. I understand you may have covered this issue in the post already but just for clarity, would you say that visible steam escaping from around the door frame is, or is most probably normal functionality?

    • Yes. It is normal. The door isnt airtight and is designed for the airflow to carry condensation out of the oven around the door. However, if the food product is steaming it would be hot enough to remove from the oven anyway ?

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