# High requency and pace makers



## burnrider (Feb 4, 2013)

My 90 yr old relative still burns some steel. He was warned by his physician about this. Pace Makers are fairly common anymore. One friend got one for data collection. They ran out of ideas after the he had unexplained heart episodes.

Anyone else been warned off the welder because of the computer?


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## Hawkeye (Feb 4, 2013)

No pacemaker, but I did put a note on the plasma cutter to shut down the computer before using it. It's located upstairs, almost directly above the welding booth. A couple of times, I've noticed that the settings on the monitor changed after a session of plasma or TIG. Never a problem with MIG. Just the HF.

Edit: Fixed spelling error.


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## burnrider (Feb 4, 2013)

Thanks Hawk

Guys with newer welders, Do they post such a warning on the machine? The micro wave has had one for years.


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## Ray C (Feb 4, 2013)

My high-frequency TIG machine has the warnings about pacemakers in the instruction manual but only shows the usual "Guy With Hair Standing-Up" drawing on the outside of the unit.


And by the way, I've been bitten by the HF TIG a couple times.  -I can see that causing problems for someone with a pacemaker.

FWIW, my last job was a Director of Engineering for a medical device company.  The amount of testing for stuff like that is off the charts!


Ray





burnrider said:


> Thanks Hawk
> 
> Guys with newer welders, Do they post such a warning on the machine? The micro wave has had one for years.


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## Ray C (Feb 4, 2013)

Hawkeye...

I had the same problem but fixed it by being religious about connecting the unit's frame ground to a solid outside earth connection.  The instructions on mine state that as correct procedure.  Take a piece of copper water pipe, pound it about 8 feet into the ground (check for water pipes and other utilities first) and connect the machines's frame ground to that.  Problem goes away.  BTW:  8 feet is a rough recommendation that should work but if you have electrical inspectors, look-up your local code first.


Ray




Hawkeye said:


> No pacemaker, but I did put a note on the plasma cutter to shut down the computer before using it. It's located upstairs, almost directly above the welding booth. A couple of times, I've notices that the settings on the monitor changed after a session of plasma or TIG. Never a problem with MIG. Just the HF.


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## bcall2043 (Feb 4, 2013)

My wife has a defibrillator/pace maker implant and she was warned about being around welding equipment, microwaves, and MRI equipment.

Kind of off topic but kind of not too far: A friend and I decided to convert a stick welder to a tig welder by adding a high frequency circuit to it. The first time we hooked all the cables and stuff together (not enclosed) we tripped the ground fault protectors in the garage and kitchen. A little more research and we leaned that shielding and grounding for these kinds of circuits is very important and better left to the professionals. The HF can be like a broadcast signal through the air.

+1 on what RayC says, ground your welding table.

Benny
The Orphanage Never Closes


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## Rbeckett (Feb 4, 2013)

Being told to stop welding is very common.  More folks are told to stop than is really neccessary.  As long as you are considerate of coiling the cables and placing yourself into the circuit you should have no problem as evidenced ny the hundreds of pacemaker owners whoo still weld.  Most Dr tend to be over protective and it results in blanket statements like no welding, no cutting, no, no ,no, but the evidence shows that the possibility of interfering with a device is almost impossible.  So if I was told to stop welding, I would ask for the evidence that supports that and make an informed decision based on that.  But, I am an old hard head, so it shows in my decisions sometimes too.
Bob


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## burnrider (Feb 4, 2013)

bcall2043 said:


> My wife has a defibrillator/pace maker implant and she was warned about being around welding equipment, microwaves, and MRI equipment.
> 
> Kind of off topic but kind of not too far: A friend and I decided to convert a stick welder to a tig welder by adding a high frequency circuit to it. The first time we hooked all the cables and stuff together (not enclosed) we tripped the ground fault protectors in the garage and kitchen. A little more research and we leaned that shielding and grounding for these kinds of circuits is very important and better left to the professionals. The HF can be like a broadcast signal through the air.
> 
> ...



Back to what Benny said; When I stand away from the ground cable and loosen the TIG collet for adjustment, it will still zap a blue spark between finger and tungsten. Would a grounded table prevent this 'broadcast' of HF to any local ground source?


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## Ray C (Feb 4, 2013)

First some very basic info about EMI/RFI and Emissions:

EMI:  Electromagnetic Interference  -These are magnetic flux waves just like from a magnet and can be very strong.  Strong magnetic waves can produce voltages by induction into any metal object (typically a coil of wire).  These do not directly interfere with radio signals but they can mess-up radio equipment.   Magnetic waves travel through the body harmlessly unless they are pulsed waves and you have metal inside you.

RFI:  Radio Frequence Interference  -These are electrical radio signal frequency waves. They are very, very low voltage waves which can (for practical discussion) only be detected and modulated.  They can mess-up radio signals.  They are typically absorbed by the body harmlessly or just pass right through (depending on frequency).  They tend to reflect off of metal objects.  Extremely strong RF, can theoretically damage humans but, it takes one heck of a source for that to happen (i.e. military grade radio transmitters).

Conducted Emissions:  These are stray signals traveling down a wire or conducted path (possibly a human).  Crummy power supplies actually send a signal back through the power cord and into your house grid and this can cause TV's etc to misbehave.  This is how Christmas light controllers work as well as "Ethernet over Wireline" computer connections.  Sometimes strong magnetic waves are induced into power cords and actually screws-up the appliance in-question.  Those are both examples of Conducted Emissions.

Welding produces all three of these types of energy.

NOTE:  I am NOT giving medical advice here.  That said, there are several types of pacemakers and monitors.  Some have external wires inside the chest cavity and this exposes them to magnetic induction.  There are wire-less types which are less vulnerable but, the type you have depends on the medical condition being addressed.  The vulnerability factors are taken into consideration in the unit and numerous precautions are taken to provide immunity from interference even from extreme sources.  Even still there are risks due to interference.  The real problem however is conduction interference.  Anyone with a heart fibulation (or monitoring) device should not (in my personal OPINION) be welding because, direct, conducted exposure interferes directly with your nerve paths.  This is NOT good for anyone with serious medical conditions.

As far as the blue spark from your TIG torch.  -You are possibly handling the electrode while the unit is still in the ramp-down stage or, it is malfunctioning.  Get it fixed or at least, ground it out to earth before handling it.

The grounding I originally mentioned was not table grounding.  I was speaking of grounding the frame of the welder enclosure unit.  The metal frame acts as a "Gaussean" shield and collects much (but not all) the EMI/RFI radiating from the internal switching power supplies or coils.  Grounding the frame takes all that energy and releases it back to mother nature instead of radiating in free-space and screwing up someone's TV/Radio or pacemaker.


Once again, I have expressed my personal OPINIONS based on good knowledge of this area and I'm NOT giving advice on what anyone should do.

Ray




burnrider said:


> Back to what Benny said; When I stand away from the ground cable and loosen the TIG collet for adjustment, it will still zap a blue spark between finger and tungsten. Would a grounded table prevent this 'broadcast' of HF to any local ground source?


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## burnrider (Feb 4, 2013)

> As far as the blue spark from your TIG torch.  -You are possibly handling the electrode while the unit is still in the ramp-down stage or, it is malfunctioning.  Get it fixed or at least, ground it out to earth before handling it.



Good info. The old Miller Econotig is always hot- no foot control, so it's searching for ground more than I thought.


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## Ray C (Feb 4, 2013)

Perhaps powering it off then, touching it to ground before handling is something to consider.  BTW:  48 volts is the known threshold of safety.  You can put your hands across a 12V car battery but with 48 volts, you're tempting fate.  Welders usually have an open circuit voltage below that threshold and are often in the 20 to 30 volt range.  There is also something called Capacitive Discharge.  The human body can be a store of built-up charge or depending on conditions, a void of charge.  The effects are additive so, touching a charged probe (depending on positive or negative electrode) can give you a zap much larger than the OC voltage of the welding unit.  It's that zap that can trigger an arrhythmia because the current is momentarily traveling through all parts of the body until voltage equilibrium is reached.

Ray


PS:  I used to make/design invitro fetal heart monitors.  Here IS some advice.  Don't handle a live TIG probe. )





burnrider said:


> Good info. The old Miller Econotig is always hot- no foot control, so it's searching for ground more than I thought.


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## Hawkeye (Feb 5, 2013)

Good advice on the cabinet ground, Ray. We went away from ground rods some years ago. Now, I have to dig in a steel plate 2 feet below the surface, in an area that will hold some ground water. Pounding rods was a lot easier.

For a welder ground, I'll see if I can still get a ground rod. I'm a pretty good shot with a hammer. I should be able to hit the sprinkler pipe on the first try with no problem.


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## Ray C (Feb 5, 2013)

A "steel" plate?  Wow, that's weird.  Steel will eventually ozidize to the point of being somewhat non-conductive.   I'm not doubting you at all... just wondering why you regulatory authority would go that direction...

In my area, we have all underground power, cable, phone etc...  People are digging and cutting into stuff all the time.  When I put up a fence some years back, I paid for a precise survey and that included a marking of all underground utilities.  They spray painted the ground where everything was buried.  I layed-out reference objects and tape measures and photographed from a thousand angles.  -Even still I get worrried when I dig in my yard.


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## Hawkeye (Feb 5, 2013)

Galvanized steel. Like the rods were. Any metal will actually form a halo the longer it is in the ground and build up a really good connection with age. Used to see that in my metal detector days. As soon as you disturbed the soil around an old nail, it was a lot harder to detect. And the little nail was actually still there, after many years.


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