PSA: Make sure ALL the breakers are off!

[gtae07]

All the ones you're working around, anyway!

I've been slowly adding "smart" switches around the house--they're pretty neat. But in the process of adding a pair for our kitchen I zapped myself pretty good.

The location in question has three switches; two control lighting in the kitchen and one (as I now know) that controls switched outlets in the living room. We'd never used that switch in ten years and honestly didn't know what it was for.

Anyway, I'd killed the kitchen lighting breaker and was working on pushing some stuff back into the box when I think my left hand hit the hot screw on the switched outlet, and my right hand hit a neutral or ground wire.



Scared the living **** out of me because I felt it going through both arms for just a split second. Then I went "WTF?!"

Eventually I realized that other switch was on a separate circuit that I hadn't killed because I didn't realize it ran there. Lesson learned. And now I know what that switch does, too!

 

[larry4406]

Trust nothing.

After breakers off put inductance probe (chicken stick) into box to check.

Glad all is well.

 

[coljar]

I always use a test pen nowadays.

 

[Richard Cranium]

test don't guess.

 

[Bert_]

I like to lick my finger and touch all the wires before I start working. Sure fire test method, hasn't let me down yet.


In all seriousness I love my tic tester (non contact voltage detector) just know it's limits. It can be fooled although usually it's a false positive rather than false negative. I've got a fluke, the cheaper ones give more false readings.

The non contact tester is not a replacement for a meter.

 

[MattT]

In all seriousness I love my tic tester (non contact voltage detector) just know it's limits. It can be fooled although usually it's a false positive rather than false negative. I've got a fluke, the cheaper ones give more false readings.

Never got a false negative with a Fluike. Plenty of false positives but that's on industrial circuits where a high impedance meter will read high voltage too.

Seen false negatives with other brands Either buy a Fluke or use the wet finger

 

[Crazyjake8493]

No need to turn all breakers off, but you should always double check for power where you're working before you begin. I've seen many houses with multiple circuits running through the same switch box or junction box.

Never trust the labels on your panel either. Recently, whenever a friend or family member buys a house while they're doing all the furniture moving I'll go trace and label every circuit in their panel for them. They're appreciative and it saves me from breaking my back on a 300lb fridge.

 

[Jim greengo]

Treat everything like its hot.

 

[rlitman]

Never got a false negative with a Fluike. Plenty of false positives but that's on industrial circuits where a high impedance meter will read high voltage too.

Seen false negatives with other brands Either buy a Fluke or use the wet finger

I trust my Klein more than the Fluke I had before it.
The Fluke glowed red when it saw voltage, but you never knew otherwise if it was working or not. The Klein has a green LED for when it doesn't sense anything. At least I know that the battery is still good.

As for false positives and false negatives, that's the nature of non-contact voltage detectors. They ALL give false positives when you bump them into things (if they don't, they're not working). Many give false negatives if the circuit grounding is iffy, or if you're not well grounded, or if wires twist or overlap in weird ways.

ALWAYS test your non-contact meter against a known voltage (I'll just use the nearest outlet) before trusting it. And check EVERY wire and terminal in a box.

 

[Negen]

I hate that electricity messes around with hearts because my muscles feel good for days after being shocked with house voltages. Glad you didn't get hurt.

P.S
Kline 8-in-1 screwdrivers will weld themselves shut if exposed to live voltage.

Sent from my G8141 using The Garage Journal mobile app

 

[Ole Slewfoot]

Their diagonal test cutters disappear in a ball of plasma if you cut a 240 wire with just one leg shut off too
If one plug went out with the breaker, it doesn't necessarily mean the other isn't still hot.

 

[MBfreak]

My $0,02´s worth.
Surprised that one box can contain several single phase phases.
In Sweden and alsoin Europe that is not allowed.

Ola

 

[Davefr]

Trust nothing.

After breakers off put inductance probe (chicken stick) into box to check.

Glad all is well.

^^ Agree. But always test the probe (or any meter) in a known energized circuit before you test what you think is a dead circuit.

Assume nothing!!

 

[Falcon67]

^^ Agree. But always test the probe (or any meter) in a known energized circuit before you test what you think is a dead circuit.

Assume nothing!!

LOL. Old house - started taking part of a bed room for a rear house entry and a pantry. Skinned the walls, plug and a couple of switches hanging from their feeds. Consulted wiring/breaker schematic, turned off appropriate breaker, latched on to the plug drop with my lineman's pliers, squeezed and POW. Wife screams, I holler ****!. "Are you all right?" "No! Means my wiring schematic is WRONG!"

Yea, pen test. Refer to my deal on moving 11 circuits in the shop - pen tested 4 and 20 times before latching on to any specific wire.

 

[vavet]

Is it code to have all the wires in a single box to be fed by same circuit breaker?
Obviously OP's is not like this, but seems like a good idea.

 

[Falcon67]

Is it code to have all the wires in a single box to be fed by same circuit breaker?
Obviously OP's is not like this, but seems like a good idea.

Never heard/read anything like that.

 

[Bert_]

Is it code to have all the wires in a single box to be fed by same circuit breaker?
Obviously OP's is not like this, but seems like a good idea.

Maybe not so common in residential but extremely common in commercial. Completely legal. This I why you should test before you start working. It's so simple to check, no need for more rules expecting the government to protect you.

I trust my Klein more than the Fluke I had before it.
The Fluke glowed red when it saw voltage, but you never knew otherwise if it was working or not. The Klein has a green LED for when it doesn't sense anything. At least I know that the battery is still good.

As for false positives and false negatives, that's the nature of non-contact voltage detectors. They ALL give false positives when you bump them into things (if they don't, they're not working). Many give false negatives if the circuit grounding is iffy, or if you're not well grounded, or if wires twist or overlap in weird ways.

ALWAYS test your non-contact meter against a known voltage (I'll just use the nearest outlet) before trusting it. And check EVERY wire and terminal in a box.

My fluke blinks once a second or so to show that it is one.

 

[vavet]

Never heard/read anything like that.

I should think more before I post. I was thinking of things like bedrooms. The only thing in that switch box is the light and ceiling fan. Later I thought about the switch box by the front door - foyer light, switched outlet in the foyer, front porch light, and post light in the front yard. It would not make sense to have all 4 of those on the same breaker.

 

[Falcon67]

Might - could have several room lights on one circuit with the wall outlets on another. Or the laundry room lights and some other room on the far side of the house. That's typical.

 

[u3b3rg33k]

Never heard/read anything like that.

I'm sure I've seen double gang boxes with dual 20s feeding 5-20's. if I had my druthers, every duplex outlet would be a separate breaker. never have to worry about not enough power in a room again.

 

[Milton Shaw]

The worst one I ran into was a 240 volt cooktop. Should have been on one double pole breaker but one leg was on a double pole breaker and the other one about 8 inches down the breaker box on a single pole breaker. Got sparks but didn't get shocked or worse. Had to turn off everything in house to find it. Joys of new kitchen remodels and working service in houses.

 

[gtae07]

I'm sure I've seen double gang boxes with dual 20s feeding 5-20's. if I had my druthers, every duplex outlet would be a separate breaker. never have to worry about not enough power in a room again.

Switched outlets are the devil’s toys. Especially when they aren’t identified as such at either end.

In the process of all this, and in addition to learning my lesson, I discovered that three locations (living room, master bedroom, and playroom) were all wired for light and fan on separate switches, but then the wires weren’t connected.

Master bedroom they put the fan on just the light switch; playroom they didn’t even put in a fan—just a light fixture.

Downstairs they have the extra wire in place but then decided to put in switched outlets instead. Next time I’m in there the outlets are being de-switched and the fan is being separated

Next house, I’m wiring myself.

 

[wyliesdiesels]

Thats called a rookie move.

ALWAYS test before doing work.

 

[CoogarXR]

Yep, and as was said, don't trust the breaker labels.

I got bit replacing a water heater in a hurry- I just turned off the "water heater" breaker. Turns out it was the range breaker, and the water heater was still live.

 

[sberry]

I hate to say it but I did it today. I had the main off to reroute a whole bunch of stuff and after I was pretty well done, was happy for the mment and wanted to restore power, turned it all on and was fukkin around getting some stuff out of the way and pushed a 12 ground wire against a 100a lug. I think it tripped about the time I shut it off. A wire about 8 inches long. I always wondered what would happen if I did that. N done about a dozen things over the years probably, this was a first.

 

[ddawg16]

I like to lick my finger and touch all the wires before I start working. Sure fire test method, hasn't let me down yet.


In all seriousness I love my tic tester (non contact voltage detector) just know it's limits. It can be fooled although usually it's a false positive rather than false negative. I've got a fluke, the cheaper ones give more false readings.

The non contact tester is not a replacement for a meter.

I use my tongue.....more exciting

 

[rlitman]

...pushed a 12 ground wire against a 100a lug. I think it tripped about the time I shut it off. A wire about 8 inches long. I always wondered what would happen if I did that...

I could see it being pretty delayed. The impedance of the 12 gauge wire would keep the dead short current below that 100A breaker's magnetic "instantaneous" part of the curve.

Scariest moment I had like that was with a short across a series bank of batteries. The wire (I think 10 gauge) instantly started to glow a dull red. When I say instantly, I mean that it switched on as fast as an incandescent light. And when I say glow, I mean that whatever light was coming off of the heated copper was shining THROUGH the black insulation, making it appear redder than the red wires next to it.

 

[Bert_]

Worst I've done was mixing up a phase on a paralleled feeder. It wasn't that big (2 2/0's per phase), the run was around 200', and it was 208v. Could have been a far worse situation.

But I tell you what when you hear wires rattling in the conduit and the transformer going BRRRRR you can shut the switch off pretty fast.

Moral of the story, check, check again, tripple check. It's more important the bigger the stuff your working on, but the small stuff can kill you too.

 

[Dirtydan69]

I like to lick my finger and touch all the wires before I start working. Sure fire test method, hasn't let me down yet.


In all seriousness I love my tic tester (non contact voltage detector) just know it's limits. It can be fooled although usually it's a false positive rather than false negative. I've got a fluke, the cheaper ones give more false readings.

The non contact tester is not a replacement for a meter.

I use a Fluke non contact pen also. Have for years. I prefer the one that has a led flashlight as I have enough **** in my pocket already. It will give a false positive and it’s not very voltage sensitive. For instance it will show hot positive on deiling fan remote units that are in the canopy. They always bleed about 7 or 8 volts when off.

 

[Jim greengo]

I'm sure I've seen double gang boxes with dual 20s feeding 5-20's. if I had my druthers, every duplex outlet would be a separate breaker. never have to worry about not enough power in a room again.

 

[bczygan]

I always call up the power company and have them shut down Fermi II.

Bill

 

[RPH]

It’s hot until you prove it’s not.

 

[nsula_country]

Thats called a rookie move.

ALWAYS test before doing work.

Very ROOKIE! Always test with AT LEAST a Fluke non-contact pencil. Usually double check with a meter too. Don't have either of these and its 120vac, brush a wire against the back of hand. Fingers will twitch if live.

As for multiple circuits in 1 box, its legal and common. I have a 5 gang switch box that I wired in our house with 3 circuits. 3 three-way dimmer switches, combo fan speed/light dimmer and a normal toggle. All Lutron Toggler series. Have another that is a 4 gang with 3 circuits...

CT

 

[Falcon67]

I always call up the power company and have them shut down Fermi II.

Bill

SCRAM on command? That's pretty good.

 

[icthruu74]

My house was built in the early 50’s with a lot of work done on it between then and when I bought it including a new panel install recently. I’ve given up on trying to trace breakers and just shut down the main anytime I’m doing anything now. Inconvenient, but hopefully safe..

 

[sberry]

The Homeline panels are fine but that style of buss takes some getting used to. I nicked my knuckle on one yesterday a couple times.

 

[memphisnate]

Probably more of an amateur move but I usually turn the lights on or plug something into the outlet I want to turn off so it's easy to tell when I got the right breaker(s) off.

 

[MattT]

Probably more of an amateur move but I usually turn the lights on or plug something into the outlet I want to turn off so it's easy to tell when I got the right breaker(s) off.

It's actually a good idea for finding breakers. I use my Fluke pen when I've got line of sight or a helper that can tell me when the light goes out. Radio works well if you don't have a helper.

That's just for finding the breaker though. Best to confirm everything is dead with a DMM or trustworthy voltage detector pen.

 

[LaneRover]

I once turned a pair of dykes into dykes with a wire stripper that strangely enough is the exact perfect size for romex . . .

 

[sberry]

Done that 2 or 3 times in my career.