'Proof' that AFCI devices really locate arcs.

[mbrooke]

Look closely at the QO magfnet structure hoe they loop the braded conductor through and then back to the bimetallic strip which is different than the C-H and BR.
But the Sqd structure is 2/3 as lond as the others. The SqD also appears to be more bust.
All use a basic clapper typ mech, one part is sort os a long horseshoe magnet nor which is pulled against a flat plate of the same width and length.
The on;t breaker that I have seen that actually uses a solonoid type structure is the MCPs up to 150a. With the MCPs your are able to adjust the mag pickup but adjusting a gap using a cam type emch.
I belive if they could get a solenoid mech to fit in these breakers it may allow them to be more closely calibrated. But the real estate may not be there to do that.

Is the copper braid looping over the pole piece insulated or bare? That might explain the lowered magnetic trip.

 

[templdl]

Is the copper braid looping over the pole piece insulated or bare? That might explain the lowered magnetic trip.

Non insulated. One thing that I did notice was how close the moving part which is the flat portion in to the stationary portion pivoting on the end toward the toggle side.

 

[Tony S]

Europe is moving away from Ferraz (Edison) fuses.

All I’ll say about them is the few panels I’ve worked on with them fitted them were downright dangerous (mainly German from the 60’s).

Why dangerous ?

Don

Quite simply fuses can not be inserted quickly. Arcing becomes a problem and leads to a high resistance between the fuse cap and base.

I trained as an AP (MV authorised person) by the DNO our equivalent of your POCO. There’s an art to inserting fuses under load or fault conditions, speed is essential if you want to live another day.

OK the largest Ferraz (Edison) fuses I’ve dealt with were 60A, the arcing is quite frightening. Type “J” that we use for LV supplies go up to 630A

We all know we shouldn’t insert fuses under load but in my line of work its normal practice.

 

[donaldelectrician]

Quite simply fuses can not be inserted quickly. Arcing becomes a problem and leads to a high resistance between the fuse cap and base.

I trained as an AP (MV authorised person) by the DNO our equivalent of your POCO. There’s an art to inserting fuses under load or fault conditions, speed is essential if you want to live another day.

OK the largest Ferraz (Edison) fuses I’ve dealt with were 60A, the arcing is quite frightening. Type “J” that we use for LV supplies go up to 630A

We all know we shouldn’t insert fuses under load but in my line of work its normal practice.

Tony S ... Hold them horses . Whoa ... i was talking about the 15A , 20A , and 25A , and 30A for Residential .

I prefer the Superior OCP that a Edison Fuse brings to the Circuit .The most dependable and reliable OCP to this day .

I have seen a few CB's that do not trip . Never a Edison Fuse .





Don

 

[Tony S]

Tony S ... Hold them horses . Whoa ... i was talking about the 15A , 20A , and 25A , and 30A for Residential .

I prefer the Superior OCP that a Edison Fuse brings to the Circuit .The most dependable and reliable OCP to this day .

I have seen a few CB's that do not trip . Never a Edison Fuse .





Don

Whatever size when inserting a fuse you’re going to get arcing under load which will burn the fuse and base contact faces. A 6A Ferraz fuse has a tiny contact area, 4mm diameter if I remember right.

The only advantage to the system, you couldn’t fit a larger fuse than the base was designed for.




PS, I hate horses.
I have a condition called ostlers foot due to them being trampled by horses.

 

[user 100]

Tony S ... Hold them horses . Whoa ... i was talking about the 15A , 20A , and 25A , and 30A for Residential .

I prefer the Superior OCP that a Edison Fuse brings to the Circuit .The most dependable and reliable OCP to this day .

I have seen a few CB's that do not trip . Never a Edison Fuse .





Don

I know I would certainly trust one of those fuses over a standard cb or afci in the event of a l-g fault, but I don't know if this type of protection would be right for residential anymore. My main problem with fused load centers is the tampering that can inevitably occur when h.o.s run out of fuses or get tired of blowing them. We have got ways to mitigate this nowadays, but still.

I know that cb panels are just as prone to hackish creativity, but at least with a cb you know there is at least a chance the ocpd will open in the advent of a l-g fault or overload vs. whatever wackiness the h.o. can cook up.

To each their own I guess, and I do think it is a little ridiculous that a lot of insurance companies demand a lightly loaded fuse box with the type s adapters be removed, just for the sake of what might happen.

 

[iwire]

I prefer the Superior OCP that a Edison Fuse brings to the Circuit .The most dependable and reliable OCP to this day

I know I would certainly trust one of those fuses over a standard cb or afci in the event of a l-g fault,

Lets not go crazy here.

Yes, they are simple and reliable on systems with under 10,000 amps fault current.

Above that point they may explode when they open.

There are a lot of dwelling units in the cities that will have more than 10,000 amps of available fault current at the main panel.

 

[templdl]

Tony S ... Hold them horses . Whoa ... i was talking about the 15A , 20A , and 25A , and 30A for Residential .

I prefer the Superior OCP that a Edison Fuse brings to the Circuit .The most dependable and reliable OCP to this day .

I have seen a few CB's that do not trip . Never a Edison Fuse .

Don

One thing that I hesitate doing is to say that one thing is better than another because you can never duplicate an event. One thing that I nowis that it is very obvious when a fuse blows as it has to be removed then if aa replacement is not handy then what?
If a breaker trips, reset the breaker and close it. Unlike a fuse if you are present when a breaker trips and you attempt to reseyt and close it if you can't latch it right away that means the thermal element must be allowed to cool off first before the breaker casn be latched. The breaker may be warm to the touch.
If the breaker can be immediately latched and closed the breaker has tripped instantaneously. But, it is not a good practice to close a breaker back into a fault. If you do attempt to do so and the breaker immediately trips again you must resolve the fault first.
With a fuse you replace the fuse and may even have the privilege of placing it back into a fault. I would much rather close s breaker back into a fault than a fuse.
I always hear that the breaker did not trip. Breakers respond to a TC curve. If there is a question whether or not it is operating correctly s calibration check can be run to verify it.
With a fuse yu ou ae to trust that it was manufactured correctly. Have you ever test a fuse to see if it operates correctly? Once maybe.
As far as many services having a greater that 10kaic fasult current availability they are all to many statements made without any really documentation, just a guess or assumption. It this were in fact an issue it would be a big safety issue.

 

[Tony S]

Lets not go crazy here.

Yes, they are simple and reliable on systems with under 10,000 amps fault current.

Above that point they may explode when they open.

There are a lot of dwelling units in the cities that will have more than 10,000 amps of available fault current at the main panel.

What happens when a fuse fails.

 

[mbrooke]

Lets not go crazy here.

Yes, they are simple and reliable on systems with under 10,000 amps fault current.

Above that point they may explode when they open.

There are a lot of dwelling units in the cities that will have more than 10,000 amps of available fault current at the main panel.

The majority have under 10,000amps, hence why we see 10kaic rated breakers 99% of the time. Its not like all resi breakers are 22kaic and edison fuses are only 10kaic.

 

[iwire]

The majority have under 10,000amps, hence why we see 10kaic rated breakers 99% of the time. Its not like all resi breakers are 22kaic and edison fuses are only 10kaic.

Don't pull that straw man stuff on me I did not say that most are over 10K.

But it is a fact that there are many times dwelling unit service panels have over 10K available sometimes well over that.

So when someone says

I prefer the Superior OCP that a Edison Fuse brings to the Circuit .The most dependable and reliable OCP to this day .

Its only superior in the correct applications, not in all applications.

Or is this another inconvenient truth for what you have been pushing?

 

[user 100]

The majority have under 10,000amps, hence why we see 10kaic rated breakers 99% of the time. Its not like all resi breakers are 22kaic and edison fuses are only 10kaic.

Mbrooke, the point is cbs still aren't as likely as fuses to explode in someones face or burn their hand when they are trying to reset an ocpd under certain conditions. Iwire and the rest of these guys have an excellent point about available short circuit current and fuses. I still don't like them as I said above due to h.o. schemes that come about due to the inconvenience of running out of fuses.

 

[mbrooke]

Don't pull that straw man stuff on me I did not say that most are over 10K.

But it is a fact that there are many times dwelling unit service panels have over 10K available sometimes well over that.

So when someone says

True, so we would use 22kaic, 65 kaic, or a series main rating.

Its only superior in the correct applications, not in all applications.

Or is this another inconvenient truth for what you have been pushing?

Thats what we are talking about, when applied correctly. Everything no matter how good will back-fire if applied incorrectly.

BTW, in regards to inconvenient truth you still haven't answered Tony's question....


http://forums.mikeholt.com/showthread.php?t=170744&page=45&p=1666769#post1666769

 

[mbrooke]

Mbrooke, the point is cbs still aren't as likely as fuses to explode in someones face or burn their hand when they are trying to reset an ocpd under certain conditions. Iwire and the rest of these guys have an excellent point about short circuit current and fuses. I still don't like them as I said above due to h.o. schemes that come about due to the inconvenience of running out of fuses.

When misapplied. When applied correctly a fuse is superior to an MCB in 120 volt circuits.

But, you are correct, what killed off fuses was larger sizes being installed and pennies being put behind them.

 

[user 100]

When misapplied. When applied correctly a fuse is superior to an MCB in 120 volt circuits.

But, you are correct, what killed off fuses was larger sizes being installed and pennies being put behind them.

No, what killed off fuses was the advent of a modern more convenient ocpd known as the circuit breaker.

 

[mbrooke]

No, what killed off fuses was the advent of a modern more convenient ocpd known as the circuit breaker.

Maybe, but insurance companies are often skeptical about fuse panels for the exact reason above.

 

[donaldelectrician]

I know I would certainly trust one of those fuses over a standard cb or afci in the event of a l-g fault, but I don't know if this type of protection would be right for residential anymore. My main problem with fused load centers is the tampering that can inevitably occur when h.o.s run out of fuses or get tired of blowing them. We have got ways to mitigate this nowadays, but still.

I know that cb panels are just as prone to hackish creativity, but at least with a cb you know there is at least a chance the ocpd will open in the advent of a l-g fault or overload vs. whatever wackiness the h.o. can cook up.

To each their own I guess, and I do think it is a little ridiculous that a lot of insurance companies demand a lightly loaded fuse box with the type s adapters be removed, just for the sake of what might happen.

100 Man ... The old Edison Based Fused system got a bad rap because it was installed when houses had 2 Lighting Circuits and 2 Recpt. Circuits .

As appliances were added ... people just kept adding the appliances to Existing Circuits . The house never got a Rewire and added circuits where needed . The Kitchen and Laundry ... Garage , shop ect.

I am going to Wire my Cabin with a Edison Based Fuse System . I will Sleep and Travel better knowing that a Edison Fuses Will Blow when called on .
Breakers are not so Reliable . Third World dose not use AFCI's ... Thank God . I will run the Cassa off of a Micro Hydro System .

I once threw away a 12 circuit Panel Board with all Neutrals Fused because I did not have a Barn yet . Excellent Shape , Copper Bus , Like New .

I could always use Fuse Wire like the Old Days . Make my own Panel with a Marble Back .


A Fussed Modern Electrical System is the Safest and most Reliable way to go .





Don

 

[user 100]

Maybe, but insurance companies are often skeptical about fuse panels for the exact reason above.

That makes absolutely no difference and doesn't change the fact that cbs came about and were seen as a reliable, more convenient, and more ho friendly alternative to fuses. Back in the '40's and '50s the old no fuze load centers were a major selling point in a lot of the new suburban developments cropping up around the country. People just liked having to reset a breaker instead of fumbling with a fuse in the dark. The stuff that iwire had mentioned too about exploding fuses is no joke; that stuff happened way back when.

Times simply change-fuses were king of the ocpd world for a long time and then came the more user friendly cbs.

 

[user 100]

100 Man ... The old Edison Based Fused system got a bad rap because it was installed when houses had 2 Lighting Circuits and 2 Recpt. Circuits .

As appliances were added ... people just kept adding the appliances to Existing Circuits . The house never got a Rewire and added circuits where needed . The Kitchen and Laundry ... Garage , shop ect.

I am going to Wire my Cabin with a Edison Based Fuse System . I will Sleep and Travel better knowing that a Edison Fuses Will Blow when called on .
Breakers are not so Reliable . Third World dose not use AFCI's ... Thank God . I will run the Cassa off of a Micro Hydro System .

I once threw away a 12 circuit Panel Board with all Neutrals Fused because I did not have a Barn yet . Excellent Shape , Copper Bus , Like New .

I could always use Fuse Wire like the Old Days . Make my own Panel with a Marble Back .


A Fussed Modern Electrical System is the Safest and most Reliable way to go .





Don

Like I said, to each their own and I agree that a properly installed fused system that interacts with the competent is perfectly safe.

 

[mbrooke]

That makes absolutely no difference and doesn't change the fact that cbs came about and were seen as a reliable, more convenient, and more ho friendly alternative to fuses. Back in the '40's and '50s the old no fuze load centers were a major selling point in a lot of the new suburban developments cropping up around the country. People just liked having to reset a breaker instead of fumbling with a fuse in the dark. The stuff that iwire had mentioned too about exploding fuses is no joke; that stuff happened way back when.

Times simply change-fuses were king of the ocpd world for a long time and then came the more user friendly cbs.

Not doubting they did, but no one can argue fuses when installed correctly are near fail safe. Im not advocating that we go back to them but worth noting imo.