ARC Fault Breakers. Your Experiences.

[radios1]

View attachment 633205

I hope these guys remembered to grease up their plugs. lol

they are probably using an isolation transformer with a shielded secondary to power it along with a GFCI, so no current to ground, it's still a hazard though, since you can get a shock from hot to neutral!..

 

[Industrial Toys]

I like isolation transformers. Shaver outlets used to have them.

I always wondered about the physics of electric shock. So say those guys are in a rubber pool, no contact with the earth, not even capacitive. And you put two leads (hot and neutral) in the water with minor seperation, like an appliance. Will someone in the water get shocked? Now what of same thing in a grounded, porcelan (sp?) coated bath tub?

 

[Scrambler82]

In 2014 Code bathrooms, and unfinished basements didn't need AFCI.
In 2020 this has been changed to ALL 120V, 1-phase 15/20 amps outlets in dwellings.

Are they better than GFCI? Are apples better than oranges?
They really do different things. And solve different problems.

With most short circuits where you have "good grounds" (green wire connected to metal parts), and a short circuit to that metal part occurs, the "good ground" lets such a large amount of short circuit current to pass that the standard breaker trips or a fuse blows. It's sort of counter-intuitive that you WANT a LARGE amount of short circuit current to occur. So you give it a nice (green wire) path.

GFCI's solve the problem when you have bad grounds (no green wires, or poor, etc..) and the short circuit current doesn't have a good path back to the transformer and current is not large enough to trip the breaker and the metal enclosure stays energized waiting for someone to come along and touch it. GFCI's trip on the tiniest of stray ground fault current.

Like other have said AFCI's compensate for poor contractors.
AFCI's are for the problem where all the current stays IN the proper wire path (i.e. no ground fault for a GFCI to detect), but a poor wiring connection creates electrical resistance at a connection. This is equivalent to creating a mini-heater at that connection (switch, receptacle, junction, etc..) in series with the normal load being operated. This heat can melt things and catch surrounding materials on fire. AFCI's are suppose to detect the arc that comes with these poor connections.
...but note: for this "mini-heater" to be created, the "normal" load has to be pulling enough current that it creates heat at the bad connection.

For most loads like lighting and motors, if there's a bad connection that adds resistance to the circuit (and reduces the voltage the load sees) the user will detect that full voltage is not getting to the load and know there's a problem (lights may flicker, motor may not start, etc..) hopefully before the "mini-heater" bad connection ignites.
But if your running a (say) space heater, you're not going to detect that it's only putting out 1000 watts instead of 1600W, meanwhile the receptacle connection is putting out 300 Watts of heat, etc...(made up numbers). GFCI's or standard breakers can't detect this mini-heater in the circuit because no current is leaking elsewhere, and there is no overload happening (the current might actually decrease with the increased circuit resistance).

If you confident wiring was installed properly, my GUT feeling is GFCI's protect better for future unintended events (like dropping radio in bathtub, insulation on a extension cord getting nicked, etc..). Again: apples and oranges.

:2cents:

I good 2 cents if you ask me, good information... I am from the era of GFCI and I tend to use them with necessary instead of the AFCI.
Thanks

Our Xmas lights tripped off two nights ago in a thunderstorm.
The protected plug for the outside, is actually wired through a GFCI inside the garage, behind my stored trailer.
The Xmas lights are thus already done for this year.
I ain't movin all that shxt!

What do you do if there is a problem and you need to get to the Panel in a hurry... "Just me" I like to keep the area in front of any Panel clear and open for quick access.

I like isolation transformers. Shaver outlets used to have them.

I always wondered about the physics of electric shock. So say those guys are in a rubber pool, no contact with the earth, not even capacitive. And you put two leads (hot and neutral) in the water with minor seperation, like an appliance. Will someone in the water get shocked? Now what of same thing in a grounded, porcelan (sp?) coated bath tub?

I always thought, it isn't the plugged in electrical appliance that is dropped in the tub, it is when the person in the tub.. in their excitement, picks up the electrical appliance and takes it out of the water, now they are the path of the electricity; wham bam... you become a wire and that is that !
120 volts has one big problem, other than just being dangerous, if you grab something that is plugged in, it tends to make your muscles contract and you grab hold of the appliance even tighter and can't let go. I don't know if the same affect happens in other voltages but I do know somewhere as the voltage goes up you get thrown away from it.
Now we can start to talk Amperage... !

Thanks for all of this info guys, good stuff for the uneducated Home Electrican !

 

[CobyRupert]

I like isolation transformers. Shaver outlets used to have them.

I always wondered about the physics of electric shock. So say those guys are in a rubber pool, no contact with the earth, not even capacitive. And you put two leads (hot and neutral) in the water with minor seperation, like an appliance. Will someone in the water get shocked?

Internet says "over 10 milliamps (0.01 amp) is capable of producing painful to severe shock, currents between 100 and 200 mA (0.1 to 0.2 amp) are lethal." (BTW: Don't ask where this information originated from. Like VW's, jets, rocket engines and landing on the moon, I think it originated from...ahem... certain German scientists.....doing experiments on certain other people in the late 30's early 40's )

These amp values are a simplification. What it doesn't detail is how long do you "cook" at those amperages. This "total caloric intake" (total energy) is determined by how fast the breaker trips. So it's not always the amplitude (amps), but the duration too. Of course with the way breakers operate, the higher the amplitude of fault current, the faster they trip. So a lower fault current (because there's more resistance in the circuit) may actually let more energy through a breaker before it trips.
Consider where in the body the current is passing: High current through limbs or fingers may cook those parts and you might live, but a little through the heart or diaphragm may be a show stopper. Or if you're in water and the fault current overpowers the tiny millivolt signals of your nervous system so your brain can't fire your muscles to keep swimming. Or if you're on a ladder and the fault current fires your muscles to "jump now".

Like all electrical physics: Ohm's law rules. When encountering multiple paths, the current splits in proportion to the resistance encountered. (Actually these are another German scientist's (Gustav Robert Kirchhoff's (1824-1887) rules expanding on fellow German's Georg Simon Ohm's (1789-1854) rules, but who's asking?)
If there really was no alternative path (through ground) back to the transformer (or if transformer was ungrounded, and no capacitance coupling), you probably wouldn't get a shock.

One would think that if both the "Hot" and the "neutral" and/or "ground" plugs fell in the water at the same time the majority of the fault current (maybe 1000 to 10,000 amps) would pass through the water in the short space between the "Hot" & "Neut" plugs until the breaker trips.
In reality, it travels in parallel circuits of different resistances, where You are one of the paths. ...and as we see above, even though you may be a much greater resistance, it doesn't take much of that (1000-10000 amp fault) current to get shocked.

 

[Industrial Toys]

We need to get those lazy criminals waiting on death row out of their cells and have them be of some use to humanity. Do you feel that? lol

I get livened up from time to time working on live stuff. Just make sure I'm not grounded and usually stand on a piece of insulated material. But I am always somehow surprised that I don't feel a thing. I guess if the linemen can't feel half a million volts, I'm not gonna feel 110V!

"They" say distilled water doesn't pass electricity, but I am confused, because water sensor probes in Diesel filters, I am playing with, rely on the conductance of water, and that will be distilled.

 

[radios1]

We need to get those lazy criminals waiting on death row out of their cells and have them be of some use to humanity. Do you feel that? lol

I get livened up from time to time working on live stuff. Just make sure I'm not grounded and usually stand on a piece of insulated material. But I am always somehow surprised that I don't feel a thing. I guess if the linemen can't feel half a million volts, I'm not gonna feel 110V!

"They" say distilled water doesn't pass electricity, but I am confused, because water sensor probes in Diesel filters, I am playing with, rely on the conductance of water, and that will be distilled.

distilled, but yet, contaminated..

 

[Chris616]

The stupid thing about GFIs is that they start to cause problems in EXACTLY the locations they were meant to serve. Hardly a point running outside extension cords in the wet, X-Mas lights or a block heater. They will trip every time!

It's illogical to complain about a ground fault circuit interrupter (GFCI) that is interrupting the circuit when there is a ground fault.

Here is one of many ways to keep the connection dry to prevent the ground fault:
Twist and Seal - Protect Your Outdoor Extension Cord Connections

Chris

 

[Industrial Toys]

I see your point, but I expect my X-Mas lighting to be leaking electrons to ground. I have far too much other stuff on my plate, to devote any time to preventing that.

 

[Chris616]

On the subject of AFCIs, I have a puzzle that some of the electricians might have some insight into.

Most circuit breaker panels are sized to fit between two studs set at 16" OC, so they are 14.5 inches wide. The space between the breaker and the side of the box is about 4 inches (depending on the manufacturer), which has never been overly generous for running wires when they enter the box at the top or bottom. AFCI or GFCI breakers are quite a bit larger, leaving only about 2.25 inches between the breaker and the side of the box.

So breakers with increased functionality are getting bigger, but not the panels that they go into. Making a panel box larger wouldn't cost much more, since the internals stay the same, but it would make wiring the breakers a lot easier. Framing a wall to accept a larger box would be simple. So why are we stuck with 14.5" wide panel boxes? Or are there wider ones now available? Or am I missing something?

(The replacement for our old FPE Stab-Lok box was a "plug-on neutral" box, which cuts down somewhat on the wires)

Chris

 

[grsthegreat]

On the subject of AFCIs, I have a puzzle that some of the electricians might have some insight into.

Most circuit breaker panels are sized to fit between two studs set at 16" OC, so they are 14.5 inches wide. The space between the breaker and the side of the box is about 4 inches (depending on the manufacturer), which has never been overly generous for running wires when they enter the box at the top or bottom. AFCI or GFCI breakers are quite a bit larger, leaving only about 2.25 inches between the breaker and the side of the box.

So breakers with increased functionality are getting bigger, but not the panels that they go into. Making a panel box larger wouldn't cost much more, since the internals stay the same, but it would make wiring the breakers a lot easier. Framing a wall to accept a larger box would be simple. So why are we stuck with 14.5" wide panel boxes? Or are there wider ones now available? Or am I missing something?

(The replacement for our old FPE Stab-Lok box was a "plug-on neutral" box, which cuts down somewhat on the wires)

Chris

All residential panels are same internal sizes. Commercial panels are generally 24" wide, but they surface mount. Homeline panels now utilize neutral bars that work with gfci and arc fault breakers so there is no white tail wire. this really frees up space in panel. As long as you take care making up a panel, the use of gfci and arc fault breakers really dont get in the way. I group all my wires in a way to make interiors very clean and dont appear overcrowded. Now if every breaker hads a white nurtral coiled tail, then the panels are a real mess