Assuming an AFCI works does as advertised...

[growler]

I don't know about that. I had to rewire a house that had 30 amp fuses but it was a strange situation. They had hooked the circuits up much like a British ring circuit. one circuit hooked up to two seperate fuses ( one at each end of the circuit). I don't know if this was an accident or if they ment to do it that way. There were two circuits done that way and a lot of melted insulation.

There was smoke but no real fire. It was summer, the wiring was 1930s vintage and that burned rubber smell was something else.

Sounds like the old fused neutral setup common in vintage discos.

No the neutrals were not fused. Both hots were fused creating a parallel feed. Depending on resistance of the cable they could draw up to 60 amps before the fuses would blow.


I had never seen so much melted insulation so it was of particular interest to me to figure out what happened. If it had been a breaker panel I would have just assumed that a breaker didn't trip but this can't happen with fuses. So I came to the conclusion that it was either hack work or a smart person trying to collect insurance. The only problem was the house didn't burn.

 

[mbrooke]

No the neutrals were not fused. Both hots were fused creating a parallel feed. Depending on resistance of the cable they could draw up to 60 amps before the fuses would blow.


I had never seen so much melted insulation so it was of particular interest to me to figure out what happened. If it had been a breaker panel I would have just assumed that a breaker didn't trip but this can't happen with fuses. So I came to the conclusion that it was either hack work or a smart person trying to collect insurance. The only problem was the house didn't burn.

Or there was a penny behind the fuse, very common. But I can guarantee you that wire saw currents well over 30amps. But even then:

...the house didn't burn.

 

[user 100]

ID guess that wire really took some overload. Ive seen a lot of #14 fused at 30amp and outside of light fixtures it generally doesn't appear to be a problem. NEC ampacity tables are very conservative.

Not that we should fuse #14 at 30 but my point is typical over fusing rarely leads to fire.

I am still convinced that 90 to 95% of all electrical fires come from high resistance connections (failed splices) and have nothing to do with arcing or overloads like we are lead to believe.

The problem I have with over fused k&t isn't so much damage from over fusing it is cumulative damage due to over fusing. I was once in the camp of leaving k&t in place if it was in good shape and 25 years ago it may have been reasonable to leave it alone. The problem is that a quarter of a century later that insulation is not 70 years old, it is now approaching the century mark. The system has only had more of a chance to become a victim of hackery and while the soldered splices are still bomb proof, the friction tape covering those splices has only gotten drier.

 

[mbrooke]

The problem I have with over fused k&t isn't so much damage from over fusing it is cumulative damage due to over fusing. I was once in the camp of leaving k&t in place if it was in good shape and 25 years ago it may have been reasonable to leave it alone. The problem is that a quarter of a century later that insulation is not 70 years old, it is now approaching the century mark. The system has only had more of a chance to become a victim of hackery and while the soldered splices are still bomb proof, the friction tape covering those splices has only gotten drier.

I agree, its hacks who most often bring down the reputation of older wiring. K&T rivals even some newer wiring methods from an overload perspective. And even if the insulation is compromised the free air and porcelain knobs around it act like a backup.

 

[donaldelectrician]

I agree, its hacks who most often bring down the reputation of older wiring. K&T rivals even some newer wiring methods from an overload perspective. And even if the insulation is compromised the free air and porcelain knobs around it act like a backup.

I always told people to plan for the K & T wiring removal sometime in the future , if not now .
I have never seen a setup like Growers ring circuits ... but have seen fused neutrals on original K&T Service .
House was circa 1906 , with some 1800's houses in the area . The Service was in excellent shape .

My cabin is not in the US . My cabin will have edison based fuses . Still the best protection available today .



Don

 

[mbrooke]

I always told people to plan for the K & T wiring removal sometime in the future , if not now .
I have never seen a setup like Growers ring circuits ... but have seen fused neutrals on original K&T Service .
House was circa 1906 , with some 1800's houses in the area . The Service was in excellent shape .

My cabin is not in the US . My cabin will have edison based fuses . Still the best protection available today .



Don

In what country can you still get fuse panels?

 

[user 100]

In what country can you still get fuse panels?

That got me to thinking-I wonder exactly when manufacturers quit making the fused load centers for residential in the USA.

 

[ptonsparky]

We just removed one that is for sale. Service upgrade and used AFCIs on all the branch circuits, minus the range and dryer. We have done it on one other home that flagged a series arc in an extension cord a week or two ago

 

[donaldelectrician]

In what country can you still get fuse panels?

I will check during my next trip to Central America . I would also prefer cartridge fuses also . At the market there is always several electrical tables with all kinds of stuff . If I had a barn to store stuff instead of traveling , I would have kept that 12 fuse circuit Panel I pulled with 12 neutrals also fused and copper bus , It was in brand new shape .

To me a Edison Fuse is the safest way to protect a circuit . I have seen a few circuit breakers fail to trip in my life .
I have confidence that the fuse will blow . If you wire a 20A circuit for each bedroom , it cuts down the use of cords when people start renting out rooms . They use heaters and hair dryers as well as computer and tv . Some will even use a small refrigerator ... I always did .

Every room gets a 20A circuit at least , is far better that using AFCI's and a better value for your construction dollars .



Don

 

[Tony S]

Regarding the comments on the British ring main, only one fuse/breaker is used. Two fuses sounds like DIY.
With BS1363 sockets it is still regarded as one of the safest systems in the world.

Not long after I came out of my apprenticeship I decommissioned a plant done in surface mounted K&T. It was a work of art, although the switch board scared me.

 

[romex jockey]

I was apprenticed to old timers who installed K&T prior to my trade experience, now i have to deal with their installs manipulation and degrade

I would also add the Ring Circuit configuration should be required reading for any US spark.

For those of you who can view it objectively, it'll definitely light up those theory synapses in the grey matter...


~RJ~

 

[iwire]

In what country can you still get fuse panels?

Some small country called the United States of America.

Due to some coordination and NEC requirements you can still get fuse type panelboards.

The company I work for has recently installed them.

http://www.cooperindustries.com/con...ards/quik-spectm_coordinationpanelboard1.html

 

[mbrooke]

Some small country called the United States of America.

Due to some coordination and NEC requirements you can still get fuse type panelboards.

The company I work for has recently installed them.

http://www.cooperindustries.com/con...ards/quik-spectm_coordinationpanelboard1.html

Next home I buy is getting one of those :thumbsup: And with those fast blow trip curves I can also argue AFCI protection

Does Schneider also make one?

 

[iwire]

And with those fast blow trip curves I can also argue AFCI protection

I assume you mean argue against AFCIs.

This reminded me I saw one of your other posts deriding AHJs for blindly enforcing AFCIs.

It is there job, to do otherwise would be deselection of duty unless a proper amendment was put into place.

 

[mbrooke]

I assume you mean argue against AFCIs.

This reminded me I saw one of your other posts deriding AHJs for blindly enforcing AFCIs.

It is there job, to do otherwise would be deselection of duty unless a proper amendment was put into place.

Lets face it, a fast trip curve is AFCI protection. Low magnetic trip (fast blow) was a tested and promising way to mitigate arc faults.

In terms of AHJ its not their job to blindly follow authority. Look at all the examples in history where that lead...

 

[user 100]

Lets face it, a fast trip curve is AFCI protection. Low magnetic trip (fast blow) was a tested and promising way to mitigate arc faults.

In terms of AHJ its not their job to blindly follow authority. Look at all the examples in history where that lead...

mbrooke, all afci "stuff" aside, its important to note that the boards overseeing laws for municipalities have assumed the responsibility to protect their denizens and they adopt the nec because the nec is still the gold standard in the USA for determining safety for electrical installs. They know that the code is written by individuals who are far more knowledgeable than they are regarding electrical systems. An inspector working for an ahj flags someone for installing standard magnetic cbs in place of afcis isn't blindly following authority-he is simply following the law.

We may not like afcis but they are required by code and thusly any of us who operate under any code that requires them must install them if they are required. We all can't pick and choose what code we want to follow.

 

[iwire]

Lets face it, a fast trip curve is AFCI protection.

Not here

Low magnetic trip (fast blow) was a tested and promising way to mitigate arc faults.

But it is not recognized by the NEC at this time

In terms of AHJ its not their job to blindly follow authority.

It absolutely is if what they are following is the adopted law / code in their jurisdiction.

Look at all the examples in history where that lead...

Provide an example.

The more you post the more it becomes abundantly clear you have little if any real world hands on experience with AHJs or wiring methods.

 

[mbrooke]

Not here

Can you explain?

But it is not recognized by the NEC at this time

Really?

See this:

(3) A listed supplemental arc protection circuit breaker installed
at the origin of the branch circuit in combination
with a listed outlet branch-circuit type arc-fault circuit
interrupter installed at the first outlet box on the branch
circuit where all of the following conditions are met:
a. The branch-circuit wiring shall be continuous from
the branch-circuit overcurrent device to the outlet
branch-circuit arc-fault circuit interrupter.
b. The maximum length of the branch-circuit wiring
from the branch-circuit overcurrent device to the
first outlet shall not exceed 15.2 m (50 ft) for a
14 AWG conductor or 21.3 m (70 ft) for a 12 AWG
conductor.
c. The first outlet box in the branch circuit shall be
marked to indicate that it is the first outlet of the
circuit.

It absolutely is if what they are following is the adopted law / code in their jurisdiction.

Yes, from a legal standpoint. Anyone can take orders, but questioning them is something else, that is my point. There are those who believe every safety claim made about them.

Provide an example.

I thought this was self explanatory. As those on trial during Nuremberg said, "only following orders"

The more you post the more it becomes abundantly clear you have little if any real world hands on experience with AHJs or wiring methods.

Of course, because I say it for what it is: The majority of people believe everything manufactures and the CPSC say without question.

 

[iwire]

Can you explain?





Really?

See this:









Yes, from a legal standpoint. Anyone can take orders, but questioning them is something else, that is my point. There are those who believe every safety claim made about them.





I thought this was self explanatory. As those on trial during Nuremberg said, "only following orders"




Of course, because I say it for what it is: The majority of people believe everything manufactures and the CPSC say without question.

Don't act stupid it is insulting

You know AFCI is a specific term and has a specific meaning and only listed AFCIs meet the current requirements of 210.12

Comparing AHJs to nazis at Nuremberg is just utterly ridiculous.

Many AHJs do question things, they still have to blindly (ignore their doubts) and enforce the adopted rules.

Seriously try to keep things realistic and not exaggerate like a frigging manufactures sales rep.

 

[mbrooke]

Don't act stupid it is insulting

Im not acting stupid, maybe I really am. I dont know. But tell me this: how does NEC 210.12 (A) 3 a,b and c work? Why is the conductor length limited to 50 and 70 feet?

This is in regard to me original statement regarding magnetic trip offering aid in AFCI protection...

You know AFCI is a specific term and has a specific meaning and only listed AFCIs meet the current requirements of 210.12

Then why is "supplemental arc protection breaker" listed under UL 489e rather then UL1699?

https://www.google.com/?gws_rd=ssl#q=ul+489e

Comparing AHJs to nazis at Nuremberg is just utterly ridiculous.

You wanted an example, I gave the most well known. Again, I thought it was self exploratory. Either way its getting off topic.

Many AHJs do question things, they still have to blindly (ignore their doubts) and enforce the adopted rules.

But most do not, ditto for those adopting the NEC. The vast majority believe AFCIs are god's gift to electrical fires, hence why so few adopting the NEC amend 210.12. One a side note, those inspectors who are aware of nuisance tripping and skepticism tend to be more lax on service upgrades when the panel is re-located.

Seriously try to keep things realistic and not exaggerate like a frigging manufactures sales rep.

I am being realistic, who questions what sales reps say other then a select few?