RF burns from a microwave??

As I recall from my amateur radio days it seems the RF burn from HV RF tends to burn deep and char the inside of the "puncture" wound. Part of why it takes so long to heal. I would imagine the microwave burn would be more thermal unless you actually got an arc.

Isn't it something like the shorter the wavelength (or higher frequency) the less it penetrates? I might have that relationship backward.

With regard to "skin effect" in metal this is correct. I don't know if the same mechanism applies with flesh. It seems at least with lower frequency (3-30mHz) high voltage RF that the arc looks more like a plasma than a simple blue line you might see from DC.

For microwaves we can call it the "frozen spaghetti effect" since the outside is too hot and the middle is frozen... ;)

I remember getting my fingers hot from tuning our HF radio antenna in the Marine Corps. The tuning knobs were real close to the 10 foot fiberglass antenna and if you weren't careful it would zap you. This was long wave HF though not 2.4-3.8 Ghz

There are several different kinds of burns one could receive from a defective Microwave oven. The first would be as mentioned a High Voltage RF electrical burn caused by the body part becoming a conductor and getting toasted along the path which the current takes. It would be almost instantaneous. It could be that the defective hinge either acted as an antenna to receive microwave energy or that it was shorted to some conductor inside.

Another type of burn would be a radiation burn caused by a leaky seal. This could be from the "defective hinge" if it cause the seal in that area to leak. This radiation burn would require some exposure time and not be instantaneous, like the HV burn. However, it might not be felt at first, as the heat built up slowly, with blood vessels attempting to carry away the excess heat. However the exposed body part would eventually "cook" causing extreme pain.

Finally, the "defective hinge" might not be conducting electricity or causing a seal to leak RF radiation, but it could be increasing in temperature due to thermal conductivity between it and some other part of the oven which might be heating through RF exposure or simple resistance heating. Then it would burn just like a conventional oven burn.

Once was burned by "microwave" ignition system in 85? Infinity Q45 vehicle engine compartment. I was installing a remote start system on the car and searching for a tach signal. As I was looking around under the hood with the engine running, my neck started feeling like it was being branded. My gold chain was too hot to touch and I began dancing around trying to keep it from making contact with my skin while it cooled off. It left a red welt around my neck when I finally got it off. Needless to say I closed the hood and found the proper signal from the instrument cluster computer.

I'd say the moral to this story is not to wear jewelry while working under the hood (bonnet for our UK friends). If it got caught in the fan, you'd have more to write about I bet.

"Microwave Ignition System"?? That is a new one to me... and I am surprised they would have loose microwaves running around in the engine compartment.

How does such a critter work??

Bill

Of course I would prefer to have my old '56 Chevy where I could do anything with it... take it apart... put it together... and all without special tool 8016645402996.

It seems unlikely that he got burned by "microwaves". If his gold chain (15-20 inches?) acted as a full-wave loop antenna, he could have been receiving RF energy in the UHF range (600-800 Mhz?). With no other electrical outlet to drain the energy, it would have all converted to heat.

There may have been a low power data transmitter used in maintenance for wireless data collection inside the engine compartment. With close proximity to the source, and excellent electrical conductivity by the gold, the current could have built up slowly, as he described until the temperature became painful, at which point the mass of the gold would have held a fairly substantial amount of heat with no other thermal conductor besides skin and clothing, which would act as a fairly good insulator.

Perhaps someone who knows these cars could elaborate on the technical specs.

Talk about getting "hot around the collar"!

Or....Perhaps the Gold Chain was touching a hot manifold and transfered some of that energy to the aforementioned body parts.

i work with a RF Safety Company did you know OHSA requires anyone working around RF to have training,any ways to awsner your question a RF burn actually Burns from the inside out so it might look like a pin hole and will be charred you need to keep it covered and clean it will take longer to heal as they are very deep burns and can cause scaring. it would take too long to explain what wavelinks burn best but i will tell you microwave are some of the worse, but then you also got your AM towers you ever touch one of these while grounded that tower will smell like burnt person for months. let me know if you have any other questions joshf@rsicorp.com