In praise of the Ground Fault Circuit Interrupter.

3270 Views 16 Replies 11 Participants Last post by Yoyizit, Jul 12, 2009

Bigplanz

Discussion Starter · Jul 11, 2009 (Edited)

I was outside this afternoon with the kids. They were playing in the pool, and I had a box fan running in the garage to cool off while I puttered around gassing up the lawn mower and preparing to do some yard work. I looked up and there stood my 2 1/2 year old daughter, dripping wet, trying to pull the plug of the fan out of the extension cord. She had it gripped tight and was pulling as hard as she could. I started to go to her as quickly as I could but before I took a step, I heard 'click' as the GFCI tripped.

She giggled because the fan stopped, daddy about had a effing heart attack, and I took the cord away from her (it was partially pulled out). I rerouted the cord and moved the fan so she couldn't get to it again, then reset the breaker. I can't tell you how thankful I am I had this in my garage. If you have a plug outdoors or in a garage that isn't GFCI protected, replace it NOW.

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PaliBob

· #2 · Jul 11, 2009

Great Message

Yoyizit

· #3 · Jul 11, 2009 (Edited)

Bigplanz said:
there stood my 2 1/2 year old daughter, dripping wet, trying to pull the plug of the fan out of the extension cord.

but before I took a step, I heard 'click' as the GFCI tripped.

She giggled

So she never felt the slightest shock?

Was she grounded?

The fan plug had a ground pin?

I wonder if the water from her hands, and not her hands, provided the leakage path to ground.

<20mA gives a 1 second trip time, <100 mA does 0.1 sec and dumps less energy into the leakage path.

Scuba_Dave

· #4 · Jul 11, 2009

One of the 1st things I did here was to install GFCI outlets outside & in the basement
I have them all around the house, deck & pool cabana (not near water)
That way no-one has any reason to run an extension cord out a window

Bigplanz

Discussion Starter · #5 · Jul 12, 2009 (Edited)

Yoyizit said:
So she never felt the slightest shock?

Was she grounded?

The fan plug had a ground pin?

I wonder if the water from her hands, and not her hands, provided the leakage path to ground.

<20mA gives a 1 second trip time, <100 mA does 0.1 sec and dumps less energy into the leakage path.

The fan only has a two prong outlet so it must be double insulated. I don't know if she was grounded or not, but I assume so, soaking wet standing on the concrete floor of the garage. She didn't give any indication she was shocked in any way. Just 'click' and the fan stopped.

According to this link, a Class A GFCI (the one that has a 6 milamp threshold) will trip in 6/1000 of a second with a greater than 6ma leak to ground.

http://www.2d2c.com/gfci.php

Red Squirrel

· #6 · Jul 12, 2009

Wow always good to see safety features of any kind go at work.

I get real nervous when my sister brings her 3 kids to my house while we're working. There's nails all over, some live wires/switches hanging loose (not anymore, but at one point) etc...

Bigplanz

Discussion Starter · #7 · Jul 12, 2009

When we moved in, the garage didn't have any receptacles, just a light socket with a pull chain. Since I have a lot of power tools (nothing fancy, just the regular circular saw, reciprocating saw, drill, angle grinder, etc) one of the first things I did was wire the garage for overhead lights and added two receptacles. Mrs Bigplanz questioned the $25 purchase at Lowes for two GFCI receptacles, but I explained it to her and she said, "Ok. if it keeps you and the kids safe then buy as many as you need."

I put two in the garage because I didn't want to bring down the whole circuit if one tripped. It was only another 12 bucks, no big deal. I left the lighting portion of the circuit unprotected since it was lighting ONLY and would never be used for any other purpose. I didn't want to lose my lights if a GFCI tripped, in other words.

Spend the money is my advice. $25 in GFCI protection probably saved my daughter's life. They are so FAST!!! Turn around, and BOOM, they are into exactly what you don't want them to be. I really think there is something to this "Guardian Angel" stuff.

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micromind

· #8 · Jul 12, 2009

I'm not much of a fan of excessive safety stuff (especially OSHAs idiotic construction rules!), but I certainly agree that GFIs are a good idea.

They aren't very expensive, and they're pretty reliable these days. When they first came out, they were pure trash though.

Rob

AndrewF

· #9 · Jul 12, 2009

I just finished installing power out to my pole light. I am putting a GFCI on the outlet portion of it.

My garage has none, but based on this thread, I'll go ahead and upgrade those circuit(s) too.

I have a 3yr old boy and a 1 year old...i can see it now.....

InPhase277

· #10 · Jul 12, 2009

AndrewF said:
I just finished installing power out to my pole light. I am putting a GFCI on the outlet portion of it.

My garage has none, but based on this thread, I'll go ahead and upgrade those circuit(s) too.

I have a 3yr old boy and a 1 year old...i can see it now.....

Do yourself and everyone else a favor and put the light itself on the GFCI too. It isn't required by the NEC (though I understand it is an amendment is some places), but the worst shock I have ever had was from a malfunctioning post light. I was kneeling on the ground searching for something I dropped in the grass, when I put my hand on the light pole to prop myself up, it got ahold of me and nearly killed me.

Several I have tested since then have showed a leak, which would be made obvious by a GFCI.

goose134

· #11 · Jul 12, 2009

Guy at work had the exact same thing happen to him. Only it was 277 and luckily the apprentice had the presence of mind to mule kick him off of it.

Good to hear a positive testimonial for the GFCI. I'm still waiting for the AFCI ones to come trickling in.

spark plug

· #12 · Jul 12, 2009

Thanking The L-rd and GFCIs!

Bigplanz said:
I was outside this afternoon with the kids. They were playing in the pool, and I had a box fan running in the garage to cool off while I puttered around gassing up the lawn mower and preparing to do some yard work. I looked up and there stood my 2 1/2 year old daughter, dripping wet, trying to pull the plug of the fan out of the extension cord. She had it gripped tight and was pulling as hard as she could. I started to go to her as quickly as I could but before I took a step, I heard 'click' as the GFCI tripped.

She giggled because the fan stopped, daddy about had a effing heart attack, and I took the cord away from her (it was partially pulled out). I rerouted the cord and moved the fan so she couldn't get to it again, then reset the breaker. I can't tell you how thankful I am I had this in my garage. If you have a plug outdoors or in a garage that isn't GFCI protected, replace it NOW.

I share your happiness from far away! This just shows how important it is to follow Rules and Regulations ALL the time! The NEC is here for our own protection! Sometimes, certain details in the National Electrical Code night seem trivial, or petty. But they are all based on experience and experiences. Some of them that had a happy ending and some tragic! Same wtih Traffic Regs. So let's resolve to stick to the rules all of the time!:thumbup::yes::no::drink

on't Drink and Drive!!!
p.s.: Soon we'll have a comic strip with all the smilies!!!

spark plug

· #13 · Jul 12, 2009

Wishing for nuisance-free AFCIs

goose134 said:
Guy at work had the exact same thing happen to him. Only it was 277 and luckily the apprentice had the presence of mind to mule kick him off of it.

Good to hear a positive testimonial for the GFCI. I'm still waiting for the AFCI ones to come trickling in.

Same goes for AFCIs! They're here to perform an important safety task. But they're not perfect, yet! But, they're getting better. The early versions were a joke. Today, the Combination AFCIs are much improved. So it goes with technology. If we look at computers (that itself is an outdated term) from a mere 20 years ago, we'd think the technology is at least Two centuries old!!!:laughing::no::drink

on't drink and Drive!!!

Yoyizit

· #14 · Jul 12, 2009 (Edited)

Bigplanz said:
The fan only has a two prong outlet so it must be double insulated. I don't know if she was grounded or not, but I assume so, soaking wet standing on the concrete floor of the garage. She didn't give any indication she was shocked in any way. Just 'click' and the fan stopped.

According to this link, a Class A GFCI (the one that has a 6 milamp threshold) will trip in 6/1000 of a second with a greater than 6ma leak to ground.

http://www.2d2c.com/gfci.php

And yet, look at the graph, fig. 6.7, in this link
http://books.google.com/books?id=NK...puHdCg&sa=X&oi=book_result&ct=result&resnum=1
The lower graph line shows 15 to 30 milliseconds reaction time for an unloaded and loaded electromechanical relay, the longer time due to the arc being quenched. This is plausible.
It also shows that typical GFCIs do not meet the UL reaction time/current spec's at these times; the next generation GFCIs may somehow respond faster.

For sure, she was grounded.
I have to think that some current passed through her, through her heart, to ground for a minimum of 15 mS. Probably the contact skin surface was very small, which limited the current.
It's scary.

That GFCI was in the right place at the right time.
GFCI, 1. Death, 0.
Let's hope Death doesn't ask for a rematch. He can go elsewhere, and pick on someone more deserving.

Re: The Guardian Angel, 35 out of ~100,000 2 yr. old girls in the US don't live to see their 3rd birthday, so this Angel is mostly on duty. Mostly.

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Bigplanz

Discussion Starter · #15 · Jul 12, 2009

Yoyizit said:
And yet, look at the graph, fig. 6.7, in this link
http://books.google.com/books?id=NK...puHdCg&sa=X&oi=book_result&ct=result&resnum=1
The lower graph line shows 15 to 30 milliseconds reaction time for an unloaded and loaded electromechanical relay, the longer time due to the arc being quenched. This is plausible.
It also shows that typical GFCIs do not meet the UL reaction time/current spec's at these times; the next generation GFCIs may somehow respond faster.

For sure, she was grounded.
I have to think that some current passed through her, through her heart, to ground for a minimum of 15 mS. Probably the contact skin surface was very small, which limited the current.
It's scary.

That GFCI was in the right place at the right time.
GFCI, 1. Death, 0.
Let's hope Death doesn't ask for a rematch. He can go elsewhere, and pick on someone more deserving.

Re: The Guardian Angel, 35 out of ~100,000 2 yr. old girls in the US don't live to see their 3rd birthday, so this Angel is mostly on duty. Mostly.

Whatever the technical aspects may be of trip curves and response times, the bottom line is it reacted fast enough to limit her exposure to apparently an undetectable level. Considering she was a dripping wet, 36 pound toddler with probably close to zero resistance to current flowing to ground, that is breathtakingly impressive performance from a safety device.

I'll remember that moment and that 'click' for the rest of my life..

deeze

· #16 · Jul 12, 2009

Man... what a great story. Many of my friends say "just do it this way... it's not code but who cares... it works fine." I always tell them that after a while your home becomes a dangerous place to live doing that garbage!!! Patch here patch there... then put kids into the mix... jeeze.
So glad to hear such a great story like that!

Yoyizit

· #17 · Jul 12, 2009

Bigplanz said:
. . .breathtakingly impressive performance from a safety device.

I'll remember that moment and that 'click' for the rest of my life..

Yes, and unlike an air bag which cancels out one deadly force with another deadly force (and so a balance must be maintained) all this does is open relay contacts faster than humans can react.

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