The AM Forum

Just a simple reminder  Voltage and the human body do not go together.

So I am working on my newly aquired FT 102. I had just finished replacing all the relays and I was beginning to do some of the modifications to the rig. After each mod I was firing the rig up to test the mod.

I had the top off of the final (mistake number 1), I had the rig plugged in and ON ( I didn't know it was on but - - yep mistake number 2) and yes finaly I put my finger where it should not have been put ( my mother always warned me about that!!)  ZAAAAAAP!!!!!

I woke up on the floor, I don't know how long I was out but I knew I hurt. I had a good lump on my head from hitting the floor, my finger was blistered on one side and had a hole on the other. I guess the good thing was the finger took the whole hit but I was having chest pains and trouble breathing. Now I figured great, I was taken out by a rice box, no diginity. I drove to the emergency room where after an EKG was performed it was determined I had a myocardial infarction ( mild heart attack). 7 hours in the hospital and then 3 days bed rest.

I found it amazing the damage done by 900v dc. The finger still hurts after 4 days!! Anyway the pics below are 4 days after the event but I think you can get the picture.

Stay tuned as I am going to start working on the rig again!!!

G

Wow, that sounds like it was a nasty experience that could have turned out much worse. Glad you are OK and recovering! Try not to get on Action News today!

73,

Rob W1AEX

(The FT-102 is a great rig and as you know, it sounds great on AM when modified. I had great fun with mine for 20 years before finally selling it last year.)

Yeah G, don't being doing that stuff! Equally glad to hear it was a sobering, but not deadly experience.


That's the spirit! Nothing like getting back on the horse that threw your ass onto the ground. At least now you'll be more methodical and cautious, with more favorable 'final' results. Not that you weren't before, but....we all know how that goes.

Losing Elvis was bad enough. 

Gary,
        I hope all is ok. Even a mild heart attack is nothing to fool around with. Be carefull!!

I have 1 cardinal rule around here: Dont muck with high voltage when you are tired!!
I broke it one night a few years ago and got a very big reminder!!

I was working on my G-76 one night after bringing it home from a fester. (you know, you just gotta hear it play!!) I had the cabinets off of both the radio and the base station power supply and both units sitting on their sides on the bench. (on the base powr supply the plate voltage is always on amd swithced by a HV relay)
The power supply started to fall over, heading for my lap. My first instinctive reaction was to grab it before it fell into my lap. I grabbed that bastard right by the HV relay!! I got nailed hard!! I then threw it up into the air to get it out of my hands, as it was coming down I grabbed it again, and right by the relay again!!
this time I just let it fall onto the bench as I jumped back. After getting nailed twice in a row by the 650v high voltage, everything on my body was hurting pretty good, especially both arms. After I regained my composure, I must have invented at least 12 new cusswords!!  I was madder than a turpentined cat!

I now sit back and laugh about it, but it taught me to "practice what I preach!!"
Like my mother used to say when I was a young JN and she was about to beat the hell out of me: "If ya dont listen, yo gotta feel"!!

Take care of yourself and remember we aint gettin no younger!!

                                                                      The Slab Bacon
   

G,

glad your ok. Give yourself a few days rest before you get back at it. I took 3 days rest from the Gonset because of battle fatigue. Going to get back to it tonite sometime. Sometimes you just have to take a break or your head will flip around 180 degrees and you'll flip out.

Gary.. please, take your time getting back on the horse, it will still be there when you're ready.  Some things we can get along without, buy YOU are not one of them! 

Be well..
Rick

Man! Am I glad your o.k.

Did almost the same thing while building and testing a 10 meter transmitter (6146's) years ago.  Was pinching the final pi net coil to get resonance since C_out was too high.  Somehow B+ got across the coupling cap or finger was in wrong place. A brilliant purple ball of flame rose out from behind the panel.  My finger was instantly crisped at the edge of the fingernail and cauterized at the same time.  That nail has an ugly growth to this day, permanently marred. Have to keep cuttng and fiing it away.

You are very lucky.

On the bright side (if there is any in situations like this) you posted this for everyone's benefit.  We Never can get too many reminders.    

...and hey,  "I was taken out by a rice box, no diginity"; it was a hollow state zorch in attempted AM service, several notches higher than the alternatives.
You "still got class" Gary.

When ever I work on HV I sing this little song......"come a little bit closer your my kind of guy", just to remind myself.
I just had a similar conversation with K1KBW Sunday at lunch about the hit he took.

 ;D That's a good technique, Frank....

by Jay and the Americans? 

"Come a little bit closer
You're my kind of man
So big and so strong
Come a little bit closer
I'm all alone
And the night is so long"


G, did this just happen or is it the big zap from a coupla years ago?

For what it's worth your left-hand  burned middle finger is a common  standard ulnar loop -  and the index is a whorl pattern fingerprint, somewhat rarer... :-)   The middle COULD be an accidental, the rarest of all, but the scar is hiding a critical delta ID.

T

Hi Gary,

Sorry to hear of your incident, but thankful that you are ok!  Thanks for sharing the reminder that we all need to be extra careful, especially as we get older.  I remember vividly the time I had a headfone jack in an old ARC-5 transmitter for metering the plate current, and it was in the B+ circuit, not the cathode.  I remember touching the metal meter case and the chassis at the same time, and got a jolt of over 600 volts.  Ever since then, I think about that whenever I work on HV stuff.  I built a 4-400 rig with 3.5 KV in my barracks at Davis Monthan AFB, and I had to take extra precautions there due to all the other troops that were potentially exposed to the danger. 

I spent the last two weeks troubleshooting a 32V2 I am restoring, and I am so forgetful that I have to remind myself to double-check that the plug is pulled and the HV is shorted before going into it.  Last night it made 100 watts to the RF, but mod bias was off.  I fixed that, then applied all the HLR mods to the audio.  Turned it on and smoke leaked out of the 2.2k resistor in the driver dropping resistor, due to an additional electrolytic in bass akwards.  Fixed that and everything worked.  So now I need to align it, and get the antenna switching working and I will be able to join the group.  Will work with PW for a while before getting the KW rigs on the air. 

When you get back to work on the current project, take your time, have fun, and be safe.  The carpenters always say measure twice, cut once.  I revised that to say double check for voltage safety before jumping in. 

Best regards,
Rick, W8KHK

G:

Hope you recover 100%.

I sold a HB 4-1000 amp as I was not confortable kaving 4kv around the shack.

I remember being bit hard with "only" 350v.

Dan

Thanks for the comments,

I am always careful around the big stuff, 3kv and 5kv on the 21E, I had my guard down on that little rice box and it bit me.

Tom this was done Sunday evening. The hit I took a few years ago was with the Henry 2k3. But in that case it just threw me across the room and burned my hands. I got back up and continued right on.

Anyway yes I was lucky and I know we all get a little too confortable around this stuff and that is when trouble hits.

G

Ouch!  Nothing like a recent one to shake ya up, huh?  Yep, the cut looks only a few days old, now that I look closer....

Yes, 900VDC can really do a job. We tend to underestimate it.

Back in 1972 (21 years old) on a hot sweaty summer day, I came across 800VDC from hand to hand. I couldn't let go since my chest and arms were paralyzed. My legs still worked - I got up and ran backwards and the cable ripped the unit out of my closed shut, paralyzed hands.

There was no blood, just coterized, 3rd degree burned, ripped open flesh sushi on my hands. It took months to heal and kept getting infected. I should have gotten stitches, but did not. I still have the scars today.  Nasty stuff.   So far have been spared any more SERIOUS events like that. That's what it took to smarten up. Still get my share of <110V type mistakes.

Glad you're OK, G,  especially the heart zap.

T

Dude, be careful! Glad you're OK, that could have been a lot worse, even from a Rice Box, if it had gotten across the old thumper. 'Course the stored energy in the caps ain't so much, so getting thrown off it is probably a good thing. Every time I turn on big rigs, including BC stuff, I figure that one mistake might be my last. I don't work on them late at night anymore. However, I can see how its easy to get relaxed dealing with 6146s and sweep tubes and receivers, until you get a stabbing reality check like you got.

Yikes, Zorch......

It makes me nervous because it's been so long since I've been nailed by anything more than 120VAC or so (last year, twice within a week). I'm very timid around any kind of HV, even the 230v outlet for the transmitter makes me focus. It would be easy to assume a 'healthy respect' for such things exists within me, but reading G's, JJ's, and others experiences makes me wonder if I'm really just long overdue?

Someone was just discussing this sorta thing on 80m over the weekend, too.

Wow!  Most unfortunate, hope you're OK now, Gary.

I can relate to your experience very vividly.  I joined the thousand volt jolt club late one night in November, 1960.  I remember the date well, because it was the night following the Kennedy/Nixon election and I had stayed up late listening to election returns on the radio while working on a transmitter.  It was about 1 or 2 AM when I was holding the microphone in one hand and reached over to tune the transmitter, and got zapped with the full plate voltage from arm to arm due to a shorted modulation transformer in an ungrounded amplifier I was using as a modulator. 

I couldn't let go of the microphone and was frozen to some part of the transmitter.  The only way I managed to get free was that I fell backwards and happened to yank the mic cord loose from the modulator by breaking the wire off from the microphone connector.  If the set screw had been a little tighter, someone would have found me hanging on the thing the next morning.  When I finally got free, both arms  retracted spastically and uncontrollably towards my chest, and I fell over backwards, busting a glass 6L6 that was lying on the floor with the back of my head.

I didn't feel any chest pains, but the next day both arms and my chest muscles were sore as hell, and I had serious burns on both hands and several fingers.  One thing that undoubtedly helped my quick recovery was being 18 years old at the time.

Before that incident, I was always getting zapped when working on the transmitter and thought little of it, but in almost 50 years since that incident, I may have seriously contacted high voltage once or twice, but only across one hand and never at that kind of voltage level.

I'm glad we are both still here to tell about our experience.

Mend quickly G. My thoughts and all that....

Gary: Be sure to use the shorting stick before installing the 872's I sent you!!!
Skip

Frank: your description of Gonset juggling cracked me up. Could you post the video on U-Tube??

Gary,
Glad you are OK.

Ive had a few- which is why I have tended to low power. Blew myself across the room working on the GK 400 with a move that was so stupid I refuse to tell the story.

Frank,

Sunday was one of those days where nothing went right. I was working on a sluggish meter for the 813 rig and had it out of its case. I kept trying to adjust the bearing and then would test it out using about 300VDC  (It would have been a 0-3000 VDC scale)

Anyway after about 30 minutes of adjusting and testing, adjusting and testing, I was not paying attention and turned on the voltage while cradling the meter in the other hand. (Both terminals touching my palm- DUH) It took off across the room like something Daisuke Matsuzaka would have thrown. Needless to say I am in the hunt for a new 0-3,000 VDC meter

About a year ago I had a rcvr on its side on the bench and my 10 YO daughter came in. She is fascinated by the stuff and reached up to touch something in the circuit. I instinctively barked at her and then explained that "One could get really really hurt if you were not careful." She hung around and not 5 minutes later I brushed the 300VDC. Not bad but I had a typical dramatic reaction.

"Oh she said, I see what you were talking about"

I sometimes feel way to Darwinian around B+

About 7 or 8 years ago I was building a linear.  It was late at night and I'm tired but kept plugging along with the project.  I had just finished building the 2kV power supply that would power it and decided to test it by powering the thing up.  I tested it without a load despite the bleeder to see what it was putting out.  I had the chassis laid wide open and for some stupid ass reason I decided I wanted to move a wire to make the wiring look neater.  The AC was removed and not paying to the possibility that the filter caps were still energized I reached in.  I took a jolt right across the palm of my hand which was touching the chassis and my thumb that brushed up against the + terminal of the filter cap.  I didn't wait long enough for the bleeder to bleed down the capacitor bank and based on the dischared time I figured I took a hit of about 1600 to 1700V across my thumb and hand.  A light bleeder.

If anyone has seen a pickle with electrodes and 110VAC voltage applied to it, my thumb looked like that pickle for the brief moment before reflex disconnected the circuit. It was a flash and a flame shot out of the end.  I ended up with a 1/8 inch hole in the thumb that turned black and like Tom became infected. I didn't suffer any heart palpitations or anything like that but man was my left arm sore. I felt like I dislocated a shoulder. Later, I had to have the scaring and infection lanced when it was apparent it wasn't going to heal normally.

I have used this lesson in the construction of my 813 rig.  Not matter what I do the shorting stick gets used when I go behind the rack and rig.

Gary,
You're very lucky and I'm glad you're still here to talk about it.  Rest up and get back on that horse but please be very careful.

And this applies to everyone else too!

Bob

Glad ur OK, OM!
It isn't any fun getting bit.
Don't do that again!

 :o thats a shocking message!
glad to hear your ok, I was just asking Bill WTK last night if he had heard from you.

Ah jeez, G, I'm glad you survived that!  I remember you gettnig bit from a Henry leenyar some years ago.

We want your melodious tones on the air for years to come.

I wonder what the hospital staff thought when you "displayed" them your middle finger? :o :o :o :o :o :o :o :o :o :o

WOW! Glad you are ok G.....

Brent W1IA :P

Boy Gary - that was a scary one...glad you are OK. First time I've heard of someone getting a MI from a bite like you did (that lived to tell about it).

Worst bite I ever got was from one of those old working model toy one lunger steam engines.  As a young kid of 12 or so (pre ham radio days) I somehow came into possession of one of them .  This particular model engine had a 120 V electric heating element in the boiler section.  It had one of those two pin connectors and matching two wire appliance cords that you used to see on electric frying pans.  One day, while I was BAREFOOT, in wet swim trunks, having just gone for a swim in the neighbors pool, I decided to play abound with this thing on our back stoop.  To provide power, I took out the bulb from the porch light, screwed in one of those light socket outlet adapters and plugged in a 2 wire extension cord. I then plugged the cord from the steam engine in. There I was, standing on the ground, barefoot, and  when I grabbed the boiler to pick it up and move it, my entire body felt like one big AC powered shaker!  When I yelled my voice had AC modulation on it! My hand froze around the cylindrical boiler and I could literally not let it go.  Luckily my brother (also barefoot and in wet swim trunks) was with me and he  was able to knock it free (he got a brief bite in the process as well), so I am still here to tell you about it.  Apparently the heating element had developed an internal short to the boiler.  Pretty scarily designed toy in retrospect.

So Gary think about the last thing you remember and the first thing you remember when you came to. You will enjoy think about it in the future.
I worked in a garage when I was a kid and had a tire explode on a change machine as I was setting the bead. It took me off my feet and I landed standing up next to the time clock where we had a newspaper article of a guy and his son killed inflating a tractor tire. Everyone watching told me said the first thing I did was grin from ear to ear because I looked at the picture and knew I was still present.
I couldn't hear for a while and had the shakes for a couple hours. After that everytime I set a bead on a tire the pop would make me jump.....Me friends at work had a lot of fun with my new found fear. I saw the big long tunnel that time.......but the light was far away

Wow Gary, that sounds like it was *too* close. Glad to hear you're mending well but  the MI is scary.

I joined the club in about 1970, while working on that 75 watter from the '64 handbook, the one with the 1625 under the chassis. I was having problems getting output into my light bulb dummy load and was troubleshooting it on it's back, balanced on the transformer at the back of the chassis. It wouldn't balance, so I had to hold the chassis to steady it with my left hand. I was powering it up right side up, then shutting it down with the key closed to hasten the draw down of the capacitors in the HV supply and flipping it over to check things and make measurements.

The last time I shut it off but forgot to key it as I was doing it, then flipped it over on it's back and reached inside to poke the parasitic suppressor on the plate cap. The caps still had substantial charge in them and I was getting it from one hand to the other. I didn't realize what was happening. My buddy Ken was in the room with me and as I started shuddering with my arms spasming I thought Ken was playing a joke on me, having grabbed me by the arms and shaking me violently. When the caps ran down or I finally shook myself free I spun around and started yelling at him to "cut it out!", only to find he was across the room from me. Then it dawned on me what had happened and it scared the crap out of me! Other than being shook up and having sore arms for a couple of days, no real problem. As others mentioned, being young (and dumb) helped.

The previous best effort was at age 7, back when I was first learning about batteries and light bulbs and stuff in cub scouts. I had run down all my D cells playing one afternoon. That year they were advertising battery rechargers on the TV, showing them plugging into the wall and then recharging various batteries. I had the cut off plug from a string of defunct Christmas series lights, so my young brain decided that if I connected my dead battery across that plug and plugged it in it would recharge. So I did that. Fortunately I couldn't manage to hold one wire with each hand on the cell and still manage to plug it in. So I transferred it to one hand holding both ends of the battery, and plugged it in with the other! ZORCH!! Knocked me on my ass. And left me buzzing, probably from the adrenaline dump. I was shaking and chattering and thought I had electricity loose in me causing that, so I went to the kitchen and got a glass or three of water to "short it out" inside me and it seemed to work. My mom hollered up the hall to "ask what that noise was". Like legions of other young experimenters, the answer was "Nothing!"   ;D

Someone mentioned a little ditty to remind themselves to be careful. Excellent idea. When I work on my homebuilt airplane, sometimes I'm racing to put things together and get a quick flight in before the sun goes down. Or I want to rush through the preflight inspection and get flying. I bring up the image to mind of a lonely tombstone with the words "He was in a hurry" on it as my old instructor said to do. Works every time.
 

I've been very lucky I think, worst has been a few brushes with 120 VAC as a kid, with AC/DC hot chassis radios and ground. And a few Tesla coil bites for fun. I am knocking on wood as I speak, because I deal with some serious HV at work these days, our power supplies are -85 kV 25 amps for one type, 30 kV DC 25 Amps on another type of rig, and 15 kV at 2 Amps on another. They are engineered to be used safely, as we have strict written procedures, red lock out, grounding policies, two-man rules  when putting the sticks across the capacitors, annual CPR training, annual capacitor shorting training, now we have an AED beside each capacitor vault.

I saw a friend almost meet his maker, when we were testing a new 3500 watt FM rig, at Broadcast Electronics, 25 years ago. I was the high power engineer for the transmitter, and he designed low level stuff, like the power control logic, the stereo generator, stuff up to 28 VDC or so. It was customary to test prototypes with the back off, to make quick changes, measure stuff, adjust the neutralization easily, etc. So here it was, pumping out 3.5 kW into a load, when he walked in from his lab, to show me something he was curious about. Before I could yell stop, he reached in the back to touch the little motor that ran a variac on the screen supply, for VSWR foldback system. Right next to this motor, was exposed 4100 VDC. Being a prototype, things weren't guarded under plastic or in their final production layout. He hit it, and his other arm was resting on the rack. He flew across the floor, and the 30 Amp 220 VAC breaker tripped on the rig. It all happened really fast. In less than a minute, he started getting up, a bit groggy, with a black mark on his finger and on the opposite elbow. His arm and finger turned colors, but he refused hospital visit, and of course, the management was pretty upset at us.

Gary,

Glad you're ok OM.  It would be a damn shame to loose that "ON the AIR" presence.  
I've been bitten a few times myself, but the worst case I saw was a tech who had gotten across a 400V/16amp pulsed circuit in a testing facility.  I guess he figured he could make adjustments between pulses?? or just forgot to de-energize the circuit.   Launched him across the room, off the -wall and stopped his ticker.  The fellow with me de-energized the place by yanking cables out of the boxes on the walls. (We didn't know what he was working on and what had gotten him at the time and he was laying across a real JS rats nest of cables and such). Did CPR on him until the Paramedics showed up.  He lived. wasn't quiet the same though...
Makes me pretty careful around the HV stuff.

Gary, glad you are OK!

I'll add two quick related stories - along with my personal motto:  A shorting stick is your best friend & never trust the bleeders or the HV meter!

I had picked up a 2KW plasma generator on a dumpster dive.  Hooked it up for testing prior to reworking it, no HV indication.  Turned it off & started poking around, took 4KV from the filter cap across my hand.  At least I was smart enuf to only have one hand stuck in there. There was no HV indication because the metering was off the bottom of the open bleeder.  

Just a couple months ago my Harris amp started acting wierd. I noticed the HV seemed high.  Turned it off and the HV hung in there for a really long time - duh.... here we go again. This time there were TWO 100W paralleled bleeders that were both open.

I have an earlier one that involves a shorting interlock, exploding panel meter, getting knocked out of my chair, big knot on my forehead and a broken nose... But I obviosly didn't learn much from that one.  Pretty lucky tho.

Be careful!   73, Bill   N2BC

Gary,
So glad to hear you are OK.I had a similar experience with a Valliant(albeit certainly not as serious)I was tired and should have gone to bed,But,just that one last thing.All it cost me was a burned finger,and a new pair of shorts.Best to you...Lee N2UDF.

Gary, I'm thankful that you survived and are ready to continue.  There are some who just take up a new hobby after a close call like that.

My HV experience occurred in 1965 (when I was 15) with the home built power supply for my first homebrew tube transmitter, a pirate transmitter for the AM broadcast band (gee, I hope the Statute of Limitations have past).  I was careless and took about 500V DC (hand to hand) from that supply.  It was like getting hit with a baseball bat and knocked me off my chair in my bedroom. Fortunately, it was a life's lesson and it made me a whole lot more cautious when working with HV, both in hobby and career.

These close calls certainly earn us respect for the voltages we play with.

Despite the hazards, our group (as AMers) have relatively few fatalities.  The only fatality I recall within the AM group over the years was Ralph, W2WME. 

Eric - WB2CAU

put "safety bleeders" on all yer 100 w bleeder rx's in the form of 1~2 megohm 2 2 watters  in parallel rx's  to hot side to ground. It will discharge them if he big ones open up...slowly, but by the time you get the case off they should be OK.

Gary,
       Thank God you're alright and are able to tell us what happened. The alternative isn't very pretty.
       I hope you're feeling a bit better each day. It's never something that anyone expects to happen to them and always someone else.

Best Regards and Good Health!
                                         Joe Cro N3IBX

Gary,
Your experience is a good reminder to all of us.  We sometimes get complacent and stuff happens.  
When I was 15 I was working on my home brew 811 modulator power supply.  I had turned off the power on the 1500W supply and trusted the wire wound bleeder.  That was a big mistake.  I went into the power supply to add an extra oil filled cap and that is the last thing I remember. I pulled the 6 ft rack over and was half out my bedroom window so they tell me.  When I woke up I was on the couch as the EMT’s were working on me....The second time happened a bit latter which I was working on an old timers amp at his QTH.  He put the bleeder for the ps in the amplifier rather than on the ps chassis!  I unplugged the cable between the amp and ps and assumed the bleeder was still doing its job...another big mistake.  It nailed my real good but I survived that one as well.  A shorting stick is now part of my tool kit when working on anything that has HV in it...
In both cases, when I recovered I got right back on the project...

Eric, I do remember Ralph W2WME electrocution several years ago.  I believe he was working on an SB-220 linear at the time.  What a tragedy...
joe GMS        

Well, it's pretty obvious that just about every ham that's active on this board has been bitten by HV at the worst and 110 to 120 AC at the least.  Many of the experiences have the same common denominator.  Capacitors carry a charge almost indefinitely (for our purposes) until discharged.  Capacitors can discharge far more current "instantaneously" than the supply can normally.  In about half of our cases we can be thankful that the supply was "off" and that the voltage died exponentially.  

Statistically our shocking experiences present an alarming prognosis.

And the amazing thing is that in all our cases our experiences weren't fatal. By definition those on the board are alive.... as dumb but very logical as that sounds, let's keep it that way!

I noticed as the thread matured, responses have gone from alarm to a little humor but in almost every case another personal story just short of tragedy was added.

I think releasing all our stories has been cathartic; we surely need to relate these experiences in the aggregate and we surely aren't going to remember each and every instance but we will think Safety First.

So once again Gary, OM, I'm glad you related your saga.  Many of us probably would have yelled "Nothing" to Ma as did one of our cohorts just like most of us  many years ago.....    been too embarassed and so forth.

Perhaps you'd like to create another section on "Safety" or at the least a sub-topic in the technical repair/homebrew section.  A copy of this whole thread might be a good start. Include this type of electrical safety as well as antennae into HV lines, mechanical safety, and so forth.

Wow, SB220 eh? That thing has a stick switch, doesn't it, to prevent removing the case while it is running. Of course a clamp will bypass it. I had mine running hot out of the case in the 1990s as I was mod'ing it. So easy to reach in and tweak, so it took a lot of restraint, and not working while tired...

This thread may go down as one of the most relevant and interesting in years.  I've found myself reading it a few times.  Some of the stories are great.  G, you might consider making it a "sticky."


Bottom line: The older we get, the more vulnerable we are and less apt to recover.  What we survived when younger may do us in now, especially when it comes to the heart.


Here's some more info about electrocution....

Even though a power supply is capable of big current (1-2 amps) the body will take only as much current as it's resistance calls for, just like a resistor and Ohm's law..

Do this test:  Take your VOM and grab the probes with dry fingers, hand to hand. I measured about 600K myself.  Then wet your fingers with spit (salty solution) and measure again. I saw about 90K.

Some statistics say we need about 18 ma through the chest to cause death by ventricular fibrillation. We can handle more DC than AC current. What sometimes happens in extreme power line cases is the heart gets stimulated so violently that it tears it's own muscles and tendons apart.  Imagine the tiny pulses from the brain pulsing the heart in normal rhythm compared to a huge charge from a HV supply.

Anyway, let's look at the current produced by 1000V at 600K for dry hands....   E/R = 1.6 ma. 

Now wet hands: 1000V at 90K =  11ma.     We're getting there.


How about 2kv?    2000v/90k =  22ma.... we are there.  Sweaty hands/arms/legs/head at 2KV is about what the electric chair used.

** The big problem is that once the top layer of skin is penetrated by the initial zap and we move into soft, salty flesh, the body resistance drops dramatically and the current then surges. This can cause the body fluids to boil and cause explosions in extreme cases in addition to torn muscles, etc..  It's much like a runaway situation when carbon trails are made during arc-overs on other materials. And it all happens in a split second.

There are also certain parts of the body with very low resistance, like behind the ears for instance. Fortunately, the hands have a thick layer of (dead) skin to slow the initial current flow if there is no immediate puncture.

Anyway, this thread has caused me to stop and reflect on safety here in the shack.

I appreciate the stories and heads-up warnings as I'm sure everyone has.

Best of luck and safety -  and keep the stories coming. 

T

I appreciate all the kind words

It was a simple stupid move on my part. It was after 9:00 at night on Sunday evening.  I had spent the entire weekend replacing all the relays and modding up the Ft 102. I was tired and decided to talk with Bill DUQ and Mr Mike on Skype.  We broke up around 9:00 pm and I decided I wasn't tired and thought I would do some more work on the FT 102.  I was tired and burnt. I must have hit the switch when I flipped the rig over to do a mod on the AF board and I didn't notice it was still plugged in. The rest was just plain stupid.

On recommendations from my doctor I went to see a cardiologists this morning and I got some good news  - --  I think. He said according to the data he received from my visit to the ER room on Sunday that I might have had a mild attack but thinks I had experienced Ventricular fibrillation which can be caused by electrical shock. He did say I was still experiencing arrhythmia from the incident and that could correct itself in time - - time will tell. Other than that I seem to have survived the ordeal and besides the headache/lump on my head, a few sore muscles, and bruised pride  - - I feel OK Fine!!

I really posted this as a reminder to all of us. I have been in this hobby for 20 years and I have been bit 3 times. Each time I can attest that it was totally avoidable had a few brain cells been in operation at the time.

Thanks again to all

G

Wow! Gary, I'm glad that you're OK!  Seems that most of us have had some "shocking" experiences in our lives at one time or another....glad to be able to live to tell about it.

My experience was with a 3x 4CX250B amplifier that developed a problem with the 2KV power supply.  I somehow got across the B+ and the next thing I knew, I was clear across the room against the wall...wondering what hit me!  In the process of being unceremoniously tossed across the room, I fell or tripped across my tool box which was on the floor and scattered tools far and wide!  Wow, it took me hours to find everything and put the tools back in the box.  It took me even longer to recover from having the stuffins knocked outta me.

A friend of mine almost met his maker, while working on a 4-1000 amp with 6KV on the plate. He somehow pulled the HV wire out of one of those Millen HV connectors while reaching around the back of the chassis and connected it to his hand while it was hot.  Needless to say....the results weren't pretty.  He ended up in the hospital with a big chunk out of his hand and severe burns.  He survived that OK, but then nearly died from a staff infection that he acquired in the hospital!

We all should be reminded to take care and be safe around High Voltages.  Don't take anything for granted when working with the stuff.  It can kill you.

Take care Gary....and may we all learn from your experience and remember to be safe.

73,  Jack, W9GT

Just heard about this last night when Brent and some of the fellows were chatting on air.

I'm glad you're OK Gary, that was quite an event, someone must like you up there.

Tom's right, this is a lesson to all of us, should be made sticky.
Just reading the experiences of others gives me a new found appreciation for even the low power rigs I've been playing with.

Hoping that you heal quickly!

Bottom line you should not be alone or tired when playing with high voltage.
My last mistake took out the 160 PDM modulator 2:00 in the morning when I should have gone to bed. It woke the XYL when the FETs blew due to a stupid mistake.

Come a little bit closer your my kind of man......

Glad you ok Gary, that's scary..

The worst shock I got was with my Valliant. I was using an external 811 modulator
which was getting the B+ off the vaillant through the accessory plug. I forgot to connect the
ground from the valliant to the ground (chassis)of the modulator. I was touching the Modulator chassis
with one hand and flipped the PTT switch on the valliant with the other. I then became ground connection.
between the two. I immediately got thrown back on my butt, saw stars for a second. No damage, but I
never forget that lesson....

Becareful folks...  Chuck

You are indeed fortunate.  That was too close for comfort. Ventricular fibrillation is what usually causes death by electrocution.  Yours must have been a very mild case, because I have always heard that once it starts, it is irreversible without the intervention of a machine called a defibrillator.

From a Wiki article:


There is a load of information on the web on this subject.  Just do a Google search, typing in <<Ventricular fibrillation, electrocution>>.

I forget his callsign, but sometime in the 80's a well-known AM'er, a W2, got across the HV in an amplifier.  Reportedly, he managed to tell his wife that he had been electrocuted before he lost consciousness.  He didn't survive.  I can still remember the sound of his voice over the air, but can't think of his name or QTH.

I think that was Ralph, W2WME.   I remember his voice well. I heard that he met his fate only several years after the fact. I think he had a BC-610.

73, Jim
WA2AJM/3

Luckily I have a big empty space between my ears that act as an insulator

Seriously, this has been a worthwhile and appropriately sobering thread

Carl /KPD

I really do not remember anything but pulling my finger out fast and then waking up on the floor. I thought all the damage was done on the finger, it went in one side and came out the other.  When I woke up I felt groggy and knew I hit my head but I just got up and went upstairs grabbed a beer and sat in the den watching TV. It was then that I had noticed the pains in my chest.  Knowing what I had just gone through I just decided to be safe and get checked out.

Go figure, I don't know and it seems to me that the Docs don't really know. How do they tell this stuff from a piece of paper with wiggly lines on it anyway? It had to be a least 2 hours after the event before they took the EKG. Interesting stuff.

AMFone has the Handbook Section and other sub-features but we don't have a section on the importance of safety. Most, if not all of the people here are dealing with older rigs that have big volts and deadly volts at that. Some of us are newbies blazing new trails down a path with old rigs and homebrew rigs wielding HV.  I know I am and I'm a newbie.  We should have a Safety First section on AMFone.  As common sense as it might seem to protect oneself, putting some safety measures in some valuable words of wisdom might be a good idea.  There might be some safety tidbits some of us could use or are not aware of as apparent as they may be.  I'd like to think of myself as a pretty common sense person but I find myself doing something stupid occasionally and reprimanding myself for being so stupid. With HV that chance is very narrow.

Chuck,

You have brought up a good point that is worth repeating and expanding upon.

For the longest time in my early years, it didn't dawn on me (with separate units) that when there is a standard (ground referenced) power supply and transmitter connected together with a (+) HV lead, that there is full HV voltage potential sitting between the two chassis if they are not bonded together.  For some reason I thought, "ground is ground" and neutral is neutral - no shock risk there.  But think about it - when the final tube's filaments are on with HV and is keyed on, there is little resistance across the tube. This causes almost the full HV to drop across the infinite and open path between the two chassis, if they are not bonded together.

This is a deadly error and easily overlooked, especially when we are first testing our modules outside of the metal bonded rack.  Many times we are saved by coax cable connections, but power supplies don't use coax connectors.

To prove this to yourself, take a 9V battery (power supply) and clip lead a 1K resistor (load) to the (+) terminal.   Then measure between the other side of the resistor (ungrounded) and the (-) terminal on the battery (ungrounded). You will measure the full (+) 9 volts.

Bottom line is always run a ground strap between the power supply and unit and also a SECOND wire as backup. This is in addition to the normal bonding that takes place IF the units are installed in a common metal rack cabinet.

These precautions are especially important if the remote unit sits on the table and the power supply is on the floor. The worst scenario imaginable is to lose the ground connection - then rest your feet on the power supply cabinet while tuning the RF deck with your hand... OUCH!

Floating the power supply circuitry above chassis will help solve the chassis risk problem, but still requires a good negative chassis connection between units... cuz what if a power supply component shorts to ground like in the case of Don's mod transformer and D-104 event?


Bottom line is, you can lose your HV + lead connection and be QRT for 15 minutes - but lose the chassis ground connection and maybe SK forever.

T

Don

I have been doing just what you are doing. The doctors are throwing all these terms at me and I spend time home using Google to learn what they are talking about.

I can say this, besides feeling sore I don't feel like any of the other stuff they are saying they think happened.

I guess that is a good thing.

G

Adds a whole new meaning to the term..."Pulling an INR.."
 :o


Seriously though Gary...

Hope a hurt finger, and scorched pride is all you end up with out of it!

Thankfully, I've never been zapped by an xmitter.  My two worst shocks involved receivers.

When I was a young JN someone gave me a Hammarlund SP-400.  While a FB receiver it has all kinds of safety hazards - 300V on the standby terminals, 365/300/120VAC on the power supply terminals, etc.  What got me was one humid summer day I decided to do an IF alignment.  Put one sweaty mitt on the front panel and gripped the metal shaft of the screwdriver (for better "feel", I guess).  What I didn't know was the IF trimmers are hot with B+.  Got 300V right across the chest; I felt like crap for a week.

The other shock is one that could get any of us with old buzzard receivers and plays into TOm's dissertation above.  My Hallicrafters SX-11 standby switches the B+ (I shoulda changed it to a AVC cutoff arrangement but I was too lazy).  One day the ground wire broke off the radio and I hit the keying switch for the xmitter (which also was wired to the SX-11 standby) and adjusted something on the receiver.  Whammo, 365V right across the heart again.  Thankfully it wasn't hot/humid and only momentary.

Either incident could have turned out very differently.  BE CAREFUL when working on these old buzzard rigs, you can get killed by receiver voltage just as easily as from an xmitter.  And if your old receiver uses a switched B+ as the standby, change it over to something that opens the ground in the RF gain circuit.  Easy to do, just don't let the Collins Collectors mafia find out.  It could save your life!

A really interesting poll for this group might be, "What boatanchor fan *hasn't* gotten zorched at least once.."

I got snapped once when I had a recently-installed 1,500" Vee beam on my dad's farm in Illinois.
A big summer storm was rolling in and I started hearing explosions from the  ham shack. The antenna's feeders were arcing several inches to a water pipe. Not piss-ant sparks, but real lightning. I ran downstairs, grabbed some auto jumper cables and went to ground the feeders with it, but I got in the way of one discharge...No damage, but knocked on my arse.

BTW, that was a hell of a DX antenna. Average height was maybe 100' out to some old cottonwoods. Aimed around 45 degrees, NNE. Mid-afternoon, during daylight, I was able to work UK2BBB on 40 meter phone.

What doesn't Kill Us makes us stronger.....
Have you noticed any new super powers?
:)

Ah..That last shock I got is why my wife sticks around.

 ;D ;D ;D

i got across the b+ of a viking 2 years before i got my ticket when (I literally knew nothing bout HV) I remember waking up on the floor, and the rig being on the floor smoking away ( all the tubes had broken)

I'm deathly concerned about having a seizure while working on a live radio. I have about 30 seconds to a minute warning  so I can get away as long as I'm smart and do it. I had a pretty bad one last night, but it didn't happen in the shack. was able to down some valium
and Glo got me on the bed so I didn't fall down and go boom.

When I feel like that, I dont even go in there. I've got to be 100% to go into the shack and work on things.

HV is just one of the things we deal with.

I am also glad you are OK. Fair Radio has a slogan "God is only a prayer away". I like to think I have been original and not blasphemous, and added to that "and a couple hundred volts is all it takes to meet Him".

Having been nailed by a variety of voltages (highest B+ was 2500V), I am a bit scared when working a high voltage rig "hot", and I think that keeps me from making too many mistakes. When I sit on the stool behind the rig with the doors open and the interlock bypassed, Every action is deliberate.

When I got the "Tucker", I found the only bleeder to be the 5-meg HV meter multiplier. With 40uF capacitance sitting there and plenty of reserve mA available, I soon added a 100mA bleed so when I turn it off, it is OFF. Also picked up a mil-spec shorting stick and I USE it.

John,
      Good point! Some OB receivers like the AR-88 I believe, has as much as 500V on them when in the standby position. I think the same may be true for HRO's, etc.

No fair getting killed with a "measley" 900 Volts.  Seriously, I'm glad you're ok.  I've had some zaps in my life, but nothing over the past 30 years which were that bad.  Before that, definitely had some bad ones.

See you at Deerfield, in any event.

Regards,

Steve

!!! :o

yikes!

whoooo...


      friggin rice boxes! 






                   _-_-Wooly Bully Two Gross Creepy Roaches

Yes, that's who it was.  Not sure of the exact rig he was working on.

But this shouldn't make us shy about working around high voltage. 

Loaded guns can be deadly, but many people like to go shooting and hunt for game all their lives with never a mishap, and remember all the howls and screams you hear at any mention of restricting gun ownership. 

One minor little lapse of attention can be fatal if you are driving a car.

The list could go on and on. We don't need safety police outlawing the possession of devices that contain high voltage. One just has to be careful and use common sense.

I thought it was a SB200

Yes, I think so too. The story goes that his wife walked in after hearing some noise and he told her that he just electrocuted himself... and then passed out and died or something like that. Pretty dramatic.

I wonder if anyone remembers the famous NJ ham who moved to Belize, SA and became V31BB, back around 1989-1991?   He became a full time DXer ham receiving "green stamps" for his rare QSL cards. Anyway, he had an ongoing feud with MFJ about their crappy amplifier and even held MFJ Junk nets. He was world-wide on 20 M daily. They wouldn't take the amp back, no how. I'm sure the nets drove MFJ crazy.  Anyway, they found him slumped over his open (and still running) MFJ amplifier one day, fried. I had met him in Dayton in '90... nice guy.

My point is, have you ever thought about the risk to family members or any rescuer who comes upon you IF you ever get fried and the circuit is still live?  Many times they, too, can get it. It's probably a good idea to instruct family members that they should never directly touch you in this situation.  They should also know how to turn off the main breaker and give CPR too.... 

Back to the real world - I'm sure this information would go over like a lead balloon with the average XYL - to say the least... but should be done... :-)


T

From what I remember of the story, it was a Heath SB-1000, which was a kit version of an Ameritron amp. Dave, W3NP, was bit (damaged a finger or two) by an SB-200 several years ago.

I use to visit Ralph a few times a year. He had a nice place just east of me.

He was working on a SB 220 amplifier and he took the B+. He fell to the floor and his wife heard the noise and came into the room and Ralph told her he had just been electrocuted just before he passed away. He was pronounced dead at the scene.

Good old Buzzard radio guy.

Gary,
I seem to remember Armstrong having that rig and you showing it to Tom and I when we visited

Gary,  Sorry you had a hard lesson/reminder.  Glad to hear you are alright.  Stay safe.

I just acquired a mushroom switch with the intent of disabling the entire station via contactor in the event of an emergency. I don't want someone coming into the station finding me slumped over a piece of equipment and try to move me only to find themselves energized and dead too. Whether it's 100 volts or 5KV, it's nothing to sneeze at. Under the right circumstances the right amount of V and return path it will nail someone.  Think of the others who don't understand your setup/station and take action to rescue you.  No point in taking others out.

Again, I stipulate this website should have a safety section to drill it home and a disclaimer. If you're worried about libelous and slanderous messages worry about safety (or lack thereof) messages too if you're telling people how to do things on a piece of equipment with HV. Hopefully someone won't tell someone to do something with a probe on a HV power supply (incorrectly) and end up dead and you're on the end of a lawsuit based on information posted here.

Just my nickel (inflation).

Emphasis mine.  I recall a "dead short" interlock on my SB-220 - it being an insulated rod that held a shorting tab away from the HV.  Lesson to learn -- DON'T BYPASS INTERLOCKS! Unplug lines and short out B+ before venturing inside HV type rigs.  I've made a practice of just walking away from a HV project for a few minutes just to clear my head during troubleshooting.  Oh yeah, DON'T TRUST BLEEDERS!

Al

Another do not trust:  Panel meters!

I scored a SB-200 for $20 or 30 at a hamfest.  It had been dropped, and the cabinet bottom was torn.  Fixed that and a few busted things inside, powered it up and the HV meter read barely off the peg.  Went at it with my Fluke 77 and promptly fried it due to the 1500V plate supply being alive and kicking.

Problem was the meter multiplier resistors were all bad (5 10 meg resistors in series, IIRC).  Had I been a little less careful I coulda killed myself, as I figured the PS was only putting out 50 volts or so (according to the front panel meter).

Agreed:

 Something should be set up to address what is being said by Bobby and the rest...I"m for that.

Main thing G is recuperating and Still with us ....Thank God...


That one time i went off on Ricks Amp for the Eye Sight Glass it wasn't to put Rick down it was to address exactly what is being said... hell I got Glass on some of my stuff that should be shielded..I know better But i like it too...LOL...

But it being broadcast on here is well different...i dunno...I'm Not trying to tell anybody what to do here..But ya know...Murphy's law man...

YO
JN

ya need an SB220 cabinet ? or is this ancient history?
I have on the someone started building a 6 tube sweep amp in. The coil looks suspiciously resonant on 11m
Cabinet is OK though

k7yoo@yahoo.com

 ;D  TNX for the offer, Skip, but that amp is LONG gone!

AM Press Exchange #98 has a brief entry on Ralph, W2WME if that helps anyone with the timeframe. Under the SPAM column:

Safety First

How sad it was to read about the passing of W2WME.  He was electrocuted while working on his amplifier.  Working late into the night, we sometimes forget just how dangerous some of the equipment can be if we are not careful.  I have had my fair share of near misses; most have come when I should have gone to bed hours before.  This kind of thing doesn't just happen to appliance operators, it can happen to anyone.  Ralph will be missed by us all.  We should not forget Ralph, or how he died.


Had a recent discussion with G over the phone about this thread along with the thought of have a simple 'safety' forum or such meant for posting tips such as shorting stick designs and so on for the newbies, as well as reminders for the old salts. As mentioned several times, it's often not the lack of knowledge that gets ya, but the complacency of time vs. strikes.

The concern is that the good information as much as the personal experiences ends up getting buried over time in the QSO section. Here's a thread from last year as an example:

http://amfone.net/Amforum/index.php?topic=10677.0

Having a 'SAFETY FIRST' heading or similar in the Handbook section as a resource and constant reminder sounds like a good idea.

My favorite quote, instilled in me by my parents while growing up, applies:

"It's what you learn after you know it all, that counts"

In this case, it could save your life.