The perfect combination of antiquated junk

mbrooke

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This is where you have to get out of the theory and into the real world. Old crumbling BX "protected" (term used loosely) by FPE breakers is a very dangerous situation,

A high impedance EGC is a dangerous situation, yes, but is 65amps into a fault always dangerous?

in my professional opinion.
Thats what he said... :p:p:p


Yes, everything works fine until there is a fault. That's when things can get ugly fast.
Which is why we have breakers and low impedance EGCs.

No idea, the routing of the cable was very convoluted through multiple j-boxes, and the cable disappeared into a finished ceiling on the other side of the basement. But couldn't be much longer than 40 to 50' from the panel to light.
What about the supply pole pig and drop? Roughly.


If so, you just proved that BX is a poor EGC.
 

peter d

Senior Member
Location
New England
A high impedance EGC is a dangerous situation, yes, but is 65amps into a fault always dangerous?
A fault by definition is dangerous. Is your name Al Hildenbrand with all this phrase parsing? :huh:



Thats what he said... :p:p:p
:?




Which is why we have breakers and low impedance EGCs.



What about the supply pole pig and drop? Roughly.
I'll PM you the address and you can figure that part out. :)


If so, you just proved that BX is a poor EGC.
Well duh, I think my position on old BX is well established from the other thread.
 

mbrooke

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A fault by definition is dangerous. Is your name Al Hildenbrand with all this phrase parsing?

Thats why we have circuit breaker, right?





Starting at 25:00, said at 25:36 and 33:28

https://www.youtube.com/watch?v=emxfsOUTkUg






I'll PM you the address and you can figure that part out.
:lol::lol::lol::lol: Good one DUDE!!!! :D:cool: Ill have the voltage sag on the local 345kv buses calculated in a few minutes for the fault that occurred at the home :p


Well duh, I think my position on old BX is well established from the other thread.
Which this proves BX is a poor EGC.
 

Jraef

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Staff member
Location
San Francisco Bay Area, CA, USA
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Electrical Engineer
Doesn't this thread boil down to mag trip levels fellas?
...
Not necessarilly. A high resistance ground fault, as this appears to be, would not allow the current to get into the mag trip range. On a 15A CB, the mag trip setting could be anywhere from 6-10x the thermal rating, so that's 90-150A. If the resistance on the ground fault was keeping it at 65A, I would not expect the mag trips to activate.

And by the way, an IEC breaker would be no different... Their trip curves, both thermal and magnetic, are basically the same as ours for residential installations. They do offer more choices in mag trips that can accommodate things like motor and transformer inrush, but that's not typically what gets installed in houses. On the other side of this is the fact that their GF breakers allow 30mA of current for human contact, we only allow 6mA. We call 30mA "Equipment Ground Fault" protection, not personnel protection. I'll take ours, thank you...
 

mbrooke

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Not necessarilly. A high resistance ground fault, as this appears to be, would not allow the current to get into the mag trip range. On a 15A CB, the mag trip setting could be anywhere from 6-10x the thermal rating, so that's 90-150A. If the resistance on the ground fault was keeping it at 65A, I would not expect the mag trips to activate.

And by the way, an IEC breaker would be no different... Their trip curves, both thermal and magnetic, are basically the same as ours for residential installations. They do offer more choices in mag trips that can accommodate things like motor and transformer inrush, but that's not typically what gets installed in houses. On the other side of this is the fact that their GF breakers allow 30mA of current for human contact, we only allow 6mA. We call 30mA "Equipment Ground Fault" protection, not personnel protection. I'll take ours, thank you...
What do they typically install in houses in terms of mag trip?
 

JFletcher

Senior Member
Location
Williamsburg, VA
I pulled the deadfront from our ~1953 FPE Stab-Lok panel last month to inspect it and see what I needed for a panel change. The two breakers that are separated from others (no breakers above or below) fell out of the panel when I removed the deadfront. Getting them back in straight was a small challenge. I wonder how many FPE have burnt up from loose deadfronts or being cocked causing bad bus bar/breaker connections.

I thought most of the problems with them were with the 2p breakers. I know the single 15A that serves the entire front side of the house has tripped 60+ times in 30 years and trips under a <25A load in less than 30 seconds (plug in a 1500W space heater and flip both heating elements on, you're in the dark very quickly). Maybe because it has cycled so much the contacts are clean (low resistance), maybe I got a good one, maybe they weren't garbage back in the 50s.
 

iwire

Moderator
Staff member
Location
Massachusetts
That FPE design counts on the cover to hold the breakers in, they have adjusting screws to bring the bus forward up against the cover. Very poor design.
 

GoldDigger

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Location
Placerville, CA, USA
Occupation
Retired PV System Designer
If a breaker fell out, I would say beyond a doubt that the stab tension was too low, unless the attached wires were incredibly heavy or tight.
 

user 100

Senior Member
Location
texas
I pulled the deadfront from our ~1953 FPE Stab-Lok panel last month to inspect it and see what I needed for a panel change. The two breakers that are separated from others (no breakers above or below) fell out of the panel when I removed the deadfront. Getting them back in straight was a small challenge. I wonder how many FPE have burnt up from loose deadfronts or being cocked causing bad bus bar/breaker connections.

I thought most of the problems with them were with the 2p breakers. I know the single 15A that serves the entire front side of the house has tripped 60+ times in 30 years and trips under a <25A load in less than 30 seconds (plug in a 1500W space heater and flip both heating elements on, you're in the dark very quickly). Maybe because it has cycled so much the contacts are clean (low resistance), maybe I got a good one, maybe they weren't garbage back in the 50s.
Breakers popping out when the df is removed is common to FPE- the design just stunk and yes the very old pre 1960's stabloks (solid brown or black color, weird hexagonal switch tip) don't seem to have some of the same bus to breaker issues/tripping problems (afaik) as the later red tip incarnations. Otoh, imo that better performance is irrelevant as those particular "good" FPE breakers are ancient, no longer sold anywhere, etc- no need to hang on to them or the tight can their stabbed in if you can afford to junk 'em.
 

JFletcher

Senior Member
Location
Williamsburg, VA
If a breaker fell out, I would say beyond a doubt that the stab tension was too low, unless the attached wires were incredibly heavy or tight.
They are tight. I was going to move the upper breaker down two spaces so that the frame/gravity/other breakers would hold them in place better but was pressed for time. It's all getting ripped out next month anyway. Moving all of the junk out of the way will take longer than the panel change.

On an aside, had a potential customer ask about her FPE fuse box; she keeps blowing fuses. While a panel change would be a good idea, she really needs more circuits for the loads she has.
 

romex jockey

Senior Member
Location
Vermont
Not necessarilly. A high resistance ground fault, as this appears to be, would not allow the current to get into the mag trip range. On a 15A CB, the mag trip setting could be anywhere from 6-10x the thermal rating, so that's 90-150A. If the resistance on the ground fault was keeping it at 65A, I would not expect the mag trips to activate.

..
This is what is interesting then Jraef.

We've a scenario where an OCPD can spike up to 6O odd amps for what i'm reading is up to 1/2 minute ,it's apparently not going to bother with the handle current for this amount of time ,instead buzzing it's discontent....

Methinks most of us have been privy to this phenomenon here...

What is happening to this circuit during this event? What is the OCPD 'seeing' or not seeing ?

~RJ~
 

JFletcher

Senior Member
Location
Williamsburg, VA
iwire, just noticed those adjusting screws you mentioned - small, one top and one bottom. Interesting.

user100, they are black with I'd guess you'd call a hex switch on it (looks more like a + sign to me). Most of the single poles anyway. The two pole are rectangular, as is the one single pole that was replaced/added - it has a red tip on the handle, fwiw.

Catalog # 116-68C, model/serial # D-886-312
 

user 100

Senior Member
Location
texas
iwire, just noticed those adjusting screws you mentioned - small, one top and one bottom. Interesting.

user100, they are black with I'd guess you'd call a hex switch on it (looks more like a + sign to me). Most of the single poles anyway. The two pole are rectangular, as is the one single pole that was replaced/added - it has a red tip on the handle, fwiw.

Catalog # 116-68C, model/serial # D-886-312
Right- the old fpe also had that t-shape (*think* this was exclusive to sp's) and when looking at the switch tip of other older fpe breakers (sp's and dp's) from the side you'll notice that angled off hex shape. Another thing is that the rating on the switch tip were stamped/engraved in small font whereas the newer red tips were not iirc. The final tell tale sign of the age is going to be the bus material-if copper its older for sure.
 

mbrooke

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I thought most of the problems with them were with the 2p breakers.


Those were worse because the internal common trip mechanism can "summer salt" (my words) and jam the other pole in the on position. Can easily be replicated by drilling open any 2 pole FPE breaker and repeatedly tripping it.



I know the single 15A that serves the entire front side of the house has tripped 60+ times in 30 years and trips under a <25A load in less than 30 seconds (plug in a 1500W space heater and flip both heating elements on, you're in the dark very quickly). Maybe because it has cycled so much the contacts are clean (low resistance), maybe I got a good one, maybe they weren't garbage back in the 50s.

The biggest offenders, and those involved in the listing scandal were from the 70s and had red colored handles.
 

mbrooke

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Breakers popping out when the df is removed is common to FPE- the design just stunk and yes the very old pre 1960's stabloks (solid brown or black color, weird hexagonal switch tip) don't seem to have some of the same bus to breaker issues/tripping problems (afaik) as the later red tip incarnations. Otoh, imo that better performance is irrelevant as those particular "good" FPE breakers are ancient, no longer sold anywhere, etc- no need to hang on to them or the tight can their stabbed in if you can afford to junk 'em.
From all the breakers Ive drilled open and panels Ive looked at in junk piles, FPE from the 70s seem to have taken a serious quality dip. Had they put better thought into manufacturing them FPE would not have been anywhere near as bad, and perhaps still produced to this day. Federal Pioneer in Canada which was a carbon copy of FPE USA was bought out by Schneider decades ago and made very reliable FPE panels until they stopped production a few years back.
 

user 100

Senior Member
Location
texas
Had they put better thought into manufacturing them FPE would not have been anywhere near as bad...
Probably so- somewhere the company apparently lost it's way. Funny how things change- it's been kicked around before by guys that were in the trade years ago about how FPE was considered to be top of the line back then- almost like Sqd qo is today.:)
 

mbrooke

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Probably so- somewhere the company apparently lost it's way. Funny how things change- it's been kicked around before by guys that were in the trade years ago about how FPE was considered to be top of the line back then- almost like Sqd qo is today.:)
Im sure in the 50s and 60s FPE was among the best, in fact IMO they made the best transformers out there. But, something took a turn and FPE went down hill.
 

romex jockey

Senior Member
Location
Vermont
Anyone read the recent FPE whistleblower write up in one of the trade rags ? , unfortunately it met it's demise in the woodstove here ...:(

~RJ~
 
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