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One thing that is kind of a drag is that GFI's can get confused. If you put in a gfi breaker and all the wire flowing out of it and all the receptacles and switches and what have you are all in good shape, then the breaker could perform. But if that were the case, then you probably did not need the GFI breaker either.Originally Posted by jadnashua
Same for putting a GFI receptacle in the first of ten receptacles: the chances that something anomalous at the fifth receptacle will trip up the breaker is real.
I try to not have more than two receptacles down stream from a GFI. In most kitchens this works fine, two circuits, two GFIs, six places to plug in counter appliances. It takes a big kitchen to need more, and then, I'd just get the customer to pay for a third circuit.
I will not trust any type of voltage tester that I can rub in my hand and make it go off.
As the owner of my company the quickest way to be unemployed is to let me see one anywhere on the job and out the door that entire crew goes.
Any meter I use must be marked category III
OK.
And so we are talking about Klien and Greenlee, and rejecting the crap from discounters.
I agree that that is not obvious. But let's just spell it out for the Harry Home Owners.
http://www.ni.com/white-paper/5019/en
Last edited by Homeownerinburb; 06-24-2012 at 06:34 PM.
Now research something that counts such as NFPA 70E or OSHA
Would you recommend that someone use this no contact Greenlee tester for residential circuits?
http://www.greenlee.com/products/DET...oduct_id=19153
"Use to detect voltage in low voltage applications ranging from 12-90 volts AC"
"12-90 volts AC"
Well, I suppose one would need to be a ******* idiot to do so. So, no, I would not.
Thanks for asking.
My point being that just because you have a meter is not all the knowledge needed to use it.
The amount of surge voltages for a dwelling 15 amp circuit will depend on the size and length of conductors from the secondary side of the supplying transformer and the point on the system being tested.
To blindly say that any meter could be used at any point of an electrical system has flaws.
A category III is the smallest meter anyone should ever purchase to test voltages in their home. There are many reasons why a high voltage surge can occur on an electrical system and unless the meter is designed to handle the surge then accidents happen.
The only non-contact meter that should be used is a clamp-on ammeter. Simply rub that meter that you have in the palm of your hand to see if there is a voltage present.
I personally know of a case where the lead man held one to the brass screw on a receptacle while his helper turned off the breaker for receptacle replacement for a dishwasher. The mechanic only has one hand because the meter said the circuit was off but something somewhere went wrong. When current started flowing through him he pulled the device into the waste pipe for the sink causing an arc. A little over a week later they removed his arm to the elbow due to tissue damage from the current flowing through that portion of his arm and the burns he received.
I highly recommend that non-contact voltage meters not be used for any reason along with any type of light emitting tester. If category III is not visible on the meter then don’t use it for testing circuits in our homes.
In the event of a high voltage surge it is possible for an arc to surge through of any type of bulb and continue for a long enough amount of time to cause severe damage to any person. What are the probabilities of this happening, I don’t know but I do know if there is even the slightest probability then I don’t want to be the one doing the testing to see. I have already seen the results and know that there is a probability that it could happen.
"I personally know of a case where the lead man held one to the brass screw on a receptacle while his helper turned off the breaker for receptacle replacement for a dishwasher. The mechanic only has one hand because the meter said the circuit was off but something somewhere went wrong. When current started flowing through him he pulled the device into the waste pipe for the sink causing an arc."
I don't understand. How would having another meter have prevented some odd arc from getting around the breaker and down this poor guy's arm, and while we are chatting, how in the world did this guy get to grabbing the brass terminal of a receptacle that is tied to a hot, regardless of the position of the breaker or any indication from any meter, Cat III or not? The voltage was not there and then it was.
Sheese. I swapped out a GFI live just the other day. The house is huge and has countless panels. I was not going to go chasing down the breaker. I was going to use good insulated tools and be careful.
What you seem to be arguing is to pull the meter out before doing any work in the house. Not that I have never done that when I was working in a panel. Especially the Zinsco crap that is so common around here.
The non-contact meter that he was using told him a lie. The breaker that the helper turned off was not the right breaker but when the Non-contact quite ticking he thought it was off.
The voltage was always there but the little liar meter said it was off. One good reason why not to have one, they are liars. A good meter would have indicated that the circuit was still live but one of those trash can fillers just are no good. Did you try rubbing it in the palm of your hand?
I will always chase down the breaker but I suppose this is because I have a full understanding that 120 volts on a 15 amp or larger circuit is more than enough to kill.
It might be due to all the safety training I dish out each day and the math we do showing just how much heat energy that is available in a 120 volt 15 amp circuit. I think that the investigations that I have been involved with either directly or indirectly where someone was badly hurt working with something as simple as a 120 volt circuit might play a role in me making full sure that the voltage is off before working on anything.
I guess that you must be getting the idea. Never and I repeat Never work anything live no matter the brand name of the panel. Pull out a good category III meter that gives me the amount of voltage on the conductor before touching anything. If it is service equipment that I am working in the meter must be a category IV.
Let’s see what we have, 120 volts times 15 amps equals 1800 watts of continuous heat and using the rule of thumb of six times the rating of the device for 120 cycles this could be 10800 watts for two full seconds or just over 3100 BTUs more heat than is needed to damage the human body. Anyone that has ever used a cutting tool and cut through a live circuit can see by the damage done to the tool just how much heat went through that tool. Wonder what that kind of heat would do to one’s arm should it flow through the skin, muscle and blood?
I would never trust any non-contact meter to assure me that the power is off. I would never connect any meter with less than a category III rating to the wiring system of any dwelling unit.
The one thing that I know for sure and certain; no one has more control over my safety than me.
Well, I take you point now. You did not make your narrative very clear.
I have never had an NC fail to tell me that juice was there, but I agree that using the full function meter before pulling anything out is an excellent idea.
People are oddly afraid of sticking probes into sockets, but that certainly beats doing it with one's finger.
I don't deny that 15 amps is about 150 times the energy needed to kick your ass, under the correct circumstances.
But I'm not giving up my NC tester.
I am also not giving up my Non Contact Tester at home........and I have a Fluke 83 and use it everyday at work....
I also have a couple of the little testers that light up with metal probes but they are junk! I would use the N-C tester rather than the cheap light up probe style anyday.....
I worked for an electrician not long after I was out of high school. We did all kinds of work....New construction and alterations. The guy I worked for routinely would test a circuit by wetting his two fingers and lightly touching wires or screws on a fixture......I thought he was nuts....but he did it many times and even I did it a few times just to check it out.
Now don't go off on me for simply mentioning the unsafe practices I have seen others do. I have been bit a few times....and know very well what lectricity can do......
Last edited by Rich B; 06-26-2012 at 05:29 AM.
From what I remember, it takes only a little more than 5 ma (0.005) amps passing through the heart to kill a man, and that would make 15 amps 3,000 times a fatal current. At 115 volts, it only takes making good skin contact to make it happen. "Good skin contact" is something determined by the situation, but if the skin is moist, good skin contact will result, and the body's water and chemical makeup do a good job of conduction.
I also, would not trust a non contact meter to verify a circuit was truly dead. My own personal meter is a Fluke 87, which is only rated Class 4, but that's good enough for what I use it for.
I am definitely not a pro plumber, but I am a pro crastinator
How much would it take to kill a Woman ?
I guess their Headlights would turn on Bright.
I use a Non Contact to tell if a circuit is ON, but not to test if a wire is dead.
After checking with a meter, I will also short out the circuit and look for sparks, Just to make for sure the line is dead before working with both hands.
Last edited by DonL; 06-26-2012 at 12:14 PM.
Don't pay someone to do a job fast, when you can do a half-fast job yourself.
Don, as usual, you are funny. Headlights are most affected by cold temperatures.
I used to know people that would do that (short out 2 wires) to trip a breaker and find which one fed that circuit. I never had the cojones to try that myself, especially in my house. I do have a voltage sniffer, but if I do use it, it is to try to find wiring behind a wall before I drill into it. It tends to give false positives because of sensitivity settings. Its not one where you inject a signal into the circuit, it just senses the 60Hz field around the conductor. Even my dogs have their own sniffers, but they only use them to check the pee mail when I take them for a walk. I hope they don't ask me for an IPod touch.
I am definitely not a pro plumber
Yes, under certain circumstances, absolutely tiny currents can cook you.
My point is that under very common circumstances, modest currents can kick your ass. Few of us have not been bit at one point or another. I get a glancing sting on the back of my hand once or twice per year. Anyone who has had anything more than a kiss from the juice will be very aware of the hazard.
That stuff can do some real harm to you. I have only had one nasty experience with it, and frankly remain amazed to this day that I am alive.
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