Welding Magnetic Threshold Tolerances

Does anyone know what the magnetic threshold tolerance is for pacemakers? I bought a Trifield Meter recently hoping it would offer some guidance in trying to resume operation of a welding power unit but it simply goes off scale when I turn the thing on. In fact, it goes off scale practically everywhere in the house like light switches and the refrigerator, etc.

So, this device is useless for the purpose. Is there a meter anywhere that offers definitive guidance as to whether welding power units and the welding operation itself are OK for a pacemaker wearer? And what is the tolerance threshold for magnetic fields like are present during arc welding operations? And are there practical methods for measuring these? Seems like reasonable questions but I have been unable to find answers.

Thanks! Charlie

3 Comments

Suggestion

by ElectricFrank - 2011-11-20 03:11:13

My suggestion would be to call St Jude and ask to talk to an engineer. I don't know what their support is like, but Medtronics has been very helpful in this regard.

The problem with measuring interference is that the pacemaker is frequency dependent as well as signal strength. It is unlikely that inexpensive consumer meters would have that ability.

I'm not a welder, but there have been several posts here recommending keeping the welding leads twisted to cancel magnetic radiation. As an engineer that sounds like a good idea to me.

You might do a search on welding here on the forum as well.

frank

Twisted Cables!!

by donb - 2011-11-20 10:11:21

Hi Charlie again, I forgot the important anti-magnetic field of twisting your ground & welding cable like a rope. This is commonly called a (gimmick) in electronics, my past occupation. I always use this method & also attach the ground lead real close on the work piece that you're welding and keep a reasonable distance of your PM from the electrode arc. Thanks!!

Welding Question!

by donb - 2011-11-20 10:11:46

Hello Charlie, As Frank suggested I have contacted both Medtronic & St. Jude and both have given me the go ahead to use my aarac welder with limitations of 125 amps. I have had 3 Medtronic PMs' and now have my 4th, a St Jude. I used my gas welding back in 1992 & finally started using my arc welder in 2008 with no ill effects. After getting my 4th PM, a St Jude, I contacted their engineering and questioned engineering a couple years ago. They said I would be OK as long as i didn't exceed 400 amps ???? When asking about Tig & Mig
high frequency welding they said I should be OK but to keep a reasonable distance from the power unit as it puts out square wave high frequency energy. I have been around these power units but kept at least 20' away from the power unit. I haven't ever noticed any effects but also have someone else do the actual Tig welding.

As I have contacted both PM manufactures maybe you could get an update on precautions, also ask how their PMs' have been improved to allow using welding equipment. Oh, 400 amps, tongue in cheek, I really question that from St Jude. Call your PM manufacturer and please post or Private Message me. Thank You Charlie!!

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