Fluke 117 Saves My Life

[whitewhiskers]

or alternate subject line, weekend handyman electrician gets to live another day. Bought the 117 earlier in the year when the price dropped below $200. Used it for the first time when the kitchen light ballast failed. Was feeling lazy and was going to just use the wall switch to cut the hot supply to the fixture. Brought the meter to the supply line and the thing lit up and beeped VOLT ALERT! Ended up flipping the main breaker to be totally safe. New ballast works, using GE LED Warm White T8 bulbs (which oddly have been discontinued, maybe that's why the first ballast burned out?).

 

[Chetlaham]

Never trust a tic tester. They do give false positives and false negatives. Especially on switch legs.

 

 

Test with leads and meter set to volts.

 

[panthera]

Switched Neutrals

In our house nearly all the switched outlets and ceiling fixtures were done by switching the neutral, not the hot.
Wow.

 

[robbinsandmyers]

I have a grey 35 year old Fluke 77 thats prob gonna live forever. Pays to spend the extra cash on a meter.

 

[kb0nes]

I'm a huge fan of Fluke meters. I got a 77 back in 1981 that still works and I have since bought about 6 more. My 289 is my current goto model although there are times when I stick with a less expensive model just in case.

Glad the meter saved you a shock, those are never pleasant. The good news is that in dry locations exposure to 120v AC is seldom life threatening, but it is best not to test the premise. I tend to often do work when circuits are live and just choose to be aware of what is hot and what is ground. Even on a deenergized circuit I try not to touch anything that would normally be hot.

Worst shock I ever had was on top of a 8 foot fiberglass ladder working on a 277v light fixture. I knew I had no path to ground so I was safe, until my elbow brushed against the aluminum drop ceiling gridwork!!! My arm was numb for a bit after that. It gave me a new resoect for 277v for sure. People talk about being shocked by 240v but one has to be a certain kind of clever to get across both legs...

 

[mattl]

Got to agree with Phil, I too work on live circuits.  Just got to know what you are doing. Often simpler to replace whatever  on a live circuit than to trek to a panel and guess what circuit to kill.

 

[whitewhiskers]

re: working on live circuits

Wow, you guys are frightening. It's a good thing our leader Mr. Unimatic1140 has a disclaimer as the first forum rule.

I took a 300VDC shock when the probe I was holding moved out of position when measuring something inside the Trigger Pulse Generator of the AN/SPS-10 Surface Search Radar. The year was 1984. Some things one never forgets...

 

[mattl]

I was referring to swapping out a switch, outlet or light fixture not electronic equipment. 120v is the max I will work on live, 220v gets killed.

 

[Chetlaham]

Reply 7

Uuh... 120 volts un-lifes more people than any other voltage. Body resistance with moist or sweaty skin can be as low as 1000 ohms, with broken skin (like cuts or scraps) resistance can drop down to 300 ohms. 

 

Using ohms law V/R=I

 

120/1000= 120ma

 

120/300= 400ma

 

 

Respiratory paralysis can occur as low as 30 milliamps.  At 100ma things become a given.

 

 

 

 The truth is people typically survive 120 volt shocks because they are poorly grounded, with dry or semi dry skin or have the ability to pull themselves off the source of the shock. This creates the notion 120 volts is safe and non lethal leading to causal attitudes about working with it. That is until the right factors come into play- the person gets sweaty while gripping metal pliers - an unclothed portion of a leg contacts grounded metal- ect. Drastically dropping the odds of a good outcome.

 

Big Clive put the let go current threshold to the test, the published data is indeed accurate and not all that conservative considering Clive is a well built dude:

 



 

 

 

 

[kb0nes]

Please note, I did say seldom and I did make the distinction of a dry environment. I didn't say that AC wasn't dangerous or that one shouldn't be careful. The fact I'm typing this is decent proof as in the past 59 years I have been hit with line voltage about 20 times. I have always been careful to know my ground potential and work single handed so line voltage isn't scary then.[this post was last edited: 10/13/2023-14:02]

 

[Chetlaham]

 

@kb0nes: I was primarily referring to MattL's reply which is listed as reply #7 in my thread feed. His post stated the following:

 



I was referring to swapping out a switch, outlet or light fixture not electronic equipment. 120v is the max I will work on live, 220v gets killed.



 

 

 

I know that electricians work live daily more times than not as that is what customers demands. I know that its often nearly impossible to trace a circuit in over-filled conduit out of an electrical room with 7 panelboards each having between 42 and 84 breakers feeding multi wire branch circuits only to realize the circuit actually comes from a life safety panel located 2 floor up in an obscure back closet. And that you can't just turn off ie a server rack/patient head-wall/stair well lighting/ect. However every-time you get hit with line voltage you're pulling the lever on a slot machine regardless of 120, 277 or 347.

 

And no offense but you prove my point. Surviving a shock 20 times over a 59 year period gives the comfort that shock number 21, 22 and 23 won't leave lasting damage. Awareness itself can only go so far.

 

[whitewhiskers]

My second electrical project this week

This time I was able to identify the breaker for the circuit, note step#2 in the instructions. The Lutron dimmer is great, so modern and elegant. My chandelier is now totally LED. According to the LED bulb literature, savings is $84 per bulb over the bulb's life which is 13 years, 3 hours per day use.

Cost of Lutron dimmer and GE LED bulbs: $55
Power Reduction: 420 watts incandescent to 54 watts LED
Energy Savings after 13 years: $588
Net Savings: $533

This assumes there won't be a bulb failure in those 13 years. There seems to have been a breakthrough in bulb design. The only detectable components in these newer bulbs are what appear to be strips of filament, which is actually the LED material. The LED bulb box picture are two special size bulbs my lamp fixture requires. The remaining 5 bulb sockets accept standard A19 bulbs.