Electric shocks

Holy Cow!

by NiceNiecey - 2016-07-29 01:42:29

Floridian, I think you definitely need to contact your cardiologist/EP right away with that question.  I'm dying to learn the answer!  You don't provide us with any info in your profile.  I was particularly interested in the type of device of you have because that might make a difference in the answers you receive.

I'll be watching for additional answers.

Niecey

ZAP!!!!

by donr - 2016-07-29 09:39:14

Electric shock is a relative thing & the efect depends on a lot of variables.  Ask your average medical professional & you will be told that you shouldn't get exposed to any shock - they have to protect their legal butts & I don't blame them.  I'm an Elecktrul Injunier & will give you an answer that perhaps is less horrible & doctrinaire.  But the bottom line is essentially the same - even though the danger is far less than than laymen would think, you still want to avoid electrical shocks if you can. Many of us in here receive shocks on occasion w/o ill effect, but it's not something we want to do, trust me on that.  PM or no PM we don't want to get a shock.

The timing of the shock with respect to the heart's location in its own electrical cycle of beating can have a big effect on safety.  Shocks don't last very long - the body immediately tries to break the connection as a built-in reaction of protection.  But get a shock to the heart while it is in its "T Wave" phase of beating & it can put you into a very serious V-Tach or Vfib situation - that can be fatal.  So there are many variables to shock effect.  That being said to scare the crap out of you, I'll give you some general info on shock effect to the body, heart & PM.  take a deep breath & read..... 

1)  No one wants to / needs to suffer an electric shock of any magnitude. It is dangerous to the well being, regardless of the pacemaker situation.

2)  I have experienced many shocks, inadvertantly, of course, since I got my Pm back in Feb 2003.  Never had an ill effect, but that does not mean it is a safe event for me or my PM.  I ave on several occasions recorded the time & date of the shock & when downloaded, my PM showed nothing at all at that time.

3) Depends on the SIZE of the jolt - 110 V or 240 V, etc.  Theres a heck of a lot of difference in wnwrgy delivered to the body as the voltage increases.  Ditto for energy delivered as the electrical resistance between you & the source goes down.  F'rinstance - supposing your crappy motor w/ the deteriorating insulation has just begun to fail & very little electric current is allowed to escape - all you will get is a little tingle - but take an old, decrepit motor w/ insulation really bad, allowing more current to escape & you will really get a jolt.

4)  As in 3), consider the situation of your body - what is its resistance?  Standing on a pool deck in bare feet, soaked by long exposure to water, all wrinkled like a breakfast prune, the resistance of that skin is very, very low compared to bone-dry foot bottoms & will really let you get a jolt through that spot.  Dry skin has a very high resistance & is your first linwe of defense - very heavily callused foot bottoms are even better - dry, hard callus is a lousy conductor.  BUT - get even a small scratch in the skin that allows your body fluids to be exposed to the outside world & it's Katy bar the door- that small pathway is like plugging an electric cord into an outlet - a nead dead short circuit thrugh your first line of resistance.  I've experienced that in a college EE lab when I had a very, very small scratch on a forearm; touched a steel rim onm the lab table top w/ that scratch while working on an experiment al piece of equipment & got lit up like a Christmas tree.  Moved my arm a fraction of an inch to intact skin - NOTHING.  My skin saved me.

5)  The electrical path through the body makes a HUGE difference.  Any path that includes the heart &/or PM is more dangerous than one that does not.  that would principally mean hand-to-hand is the worst situation.  Electrical current takes the shortest path - always.  Hand to upper arm on the same side is almost (NOTE, only almost) a non starter as far as seriousness is concerned.  Hand to opposite foot is a bad one. Foot to foot - again not as bad.  But these descriptions are all relative in a zone of effect that is NEVER good.

6)  THEORETICALLY - the PM itself should be safe from any electrical shock because of the way it is designed.  It is sealed in a Titanium case that should shield it from any current getting inside of it.  Electric current ALWAYS resides on the OUTSIDE of an electrical conductor, so a completely sealed case will allow no current inside.  The leads are shielded in a conductive shield, covered by an insulated cover that is capable of resisting the body's highly corrosive fluids & carefully attached to the case.  The only part of the system exposed to outside electric current is inside the heart, where there are conductive spots on them for operation of the system for its own current return to the PM when it fires.

7)  I'm appalled at your statement about the condition of grounding in pools/spas.  I installed my own Spa & remember the extreme grounding that I had to install - the motors were/are all rated for wet conditions & there was an independent case ground straight back to source going through a GFCI (Ground Fault Circuit Interrupter) breaker to protect against just such failures in the system.  There has to be that protection - at 240 V, any ground fault would probably light you up & slowly fry you like a hot dog.  Not good!

8)  Buy yourself a good pair of shrimper's boots to wear - insulate yourself from the wet deck - that's a good start.  Wear a thin, high quaity, insulating glove.  Protect yourself at the skin-source interface.

9) Get a device that checks for just such failures & use it before servicing any pool before you start.  Doesn't matter whether you have a PM or not - this is an unsafe situation & should NOT be toerated.  Owners of pools w/ such electrical leaks are harboring a very dangerous physical safety & legal liability situation that you should not expose yourself to.

10)  Get another job if the situation is that bad.

Donr

DonR

by BillH - 2016-07-29 10:43:33

I am with you, I am more concerned about the safety of the users of the pool than it's effects on the PM.

The input circuitry have limiting devices. They have to withstand internal or external hits from defiberators.

BTW, in a residential pool any ground fault would be 120 volts.

However, in commercial pools it could 208, 240, or 480. Maybe even higher in the large water parks.

Nice little summary

by Glenscifan - 2016-07-29 19:03:45

Thanks for the run-through Donr. Some interesting little tidbits. Knowledge is power. I play around in electrical panels at work, and it's reassuring to go through the reasoning you laid out. Don't really want a tickle, but I know it's bound to happen. 

FYI, My pool installer didn't do a good grounding job. And "forgot" to properly seal the inlet to the conduit on the motor. I went by afterwards and did it properly. And my pump is 240 volts. These things are not so uncommon.