Well, that's certainly a good reason for keeping the door open and exposing live parts.

Would one of you pros explain why this idea is ridiculous? Or is it?

And this is from the 50's? My folks' house was built in 1949, and had a screw-in plug fuse panel that looked a lot safer than this.

Sure, when it is used in the manner the manufacturer intended. With the multiple violations/hazards I see in this picture, I hope this smarty-pants owner has his liability insurance paid up.

Let's start with leaving the door open, exposing the live buss and fuses;

Add the tap off the LINE bus with the white asbestos covered wire;

Add the attachment of the worklite to the can for a "neutral" (Bet the lite is used to find dead fuses);

Add the RED wire at the bottom which is at least another unfused tap or is more likely bypassing that bottom fuse!



One of the stupidest excuses I've heard in years. If things in that panel are getting so hot that the fuses are blowing from the heat, the whole panel is a fire waiting to happen! And what if the fan quits? Now you have an open panel to let the potential fire/arc from exploding fuses out in the open.

Boo-de-freakin-hoo!!!! So the tenants lose power because they're overloading the circuit. It'll be a lot more inconvenient when the building burns down!

There are exceptions to every rule and this situation fits that call.

Unless it's bypassed by the piece of red THHN.

To Tommy O.: I sincerely hope you didn't touch any of the electrical system in that entire building. You may have left yourself open to some grave liability thanks to that owner's cavalier and incredibly foolish attitude toward electricity!!

I give that owner the Darwin Award of the Millenium!!

edited to add: I wish I could have used both the Exclamation and angry post icons on this one.....never have I seen such raging stupidity!!!

Heat deterioration which is a cause of metal fatigue (loosing tension) at fuse clips, which causes further heat related deterioration has been a reason for replacement of this type distribution panel.

Look at the photo, 3rd & 4th fuses have 'tensioners' on the fuseholders.

As to the 'open' bare buss and terminations..
I would say...."close the door". However...is this panel only accessable to qualified personel??

John

John, accessable to qualified personel or not, this is bad news all around.

There is absolutely NO excuse for a lot of what is shown in that picture or the lame explanation offered by the building owner.

Over the years, I have heard a lot of 'lame excuses'! Also, I've seen a lot of fused distro panels, and a lot of 'fans' being used to help cool equipment. Fortunately, the owners listened to reason, and replaced the disasters waiting to happen.
I am not advocating what is in this post, nor the excuses that are presented (lame).
As an AHJ, I would have to cite this as unsafe conditions, and request immediate replacement, or repairs, if possible.
John

Maybe the fan is only necessary to cool the specific fuse which feeds the fan itself......

What a mess. And the owner's response suggests to me that he's desparately trying to sound as though he knows what he's talking about when in fact he has no idea.

Don't know if it's THAT bad (the fan thing, not the other violations). A guy over at a German board told this story: panel of a bowling alley, about 10 years old. When it gets hotter in summer the breakers start tripping randomly . Electrician measured, 40 amp breaker with about 28 amps load... replaced breakers several times with different brands... no result. Only a fan helps.

Tex:
IF cooling airflow was required, then mfg's would install ventilation fans on the panels.

Heat disapation from branch circuit breakers is dependent of heat from adjacent cb's. Multiple cb's that operate 'warm/hot' and are next to each other cannot disapate heat. Add to this that heat 'rises'. I don't know the engineering terms, but I see the above in real life.

One situation was 1/2 size GE breakers installed in a comm application, lighting circuits loaded to 12 amps, (#10 awg) and the branch breakers were HOT. Replaced cb's, same situation....removed circuits to a sub-panel, installed full size cb's, problem gone.

John

Well then,
What do we have here?.
I hope that this "panel" is way out of the way of any kids looking to touch the pretty looking tubes and shiny metal bits.
Is this panel of a propreitry type or has this been made from scratch?, I've never seen a thing like this before with so much bare live metal.
High Rupturing Capacity fuses of the type used above, are designed to run cool under normal loading, even to the extent that they have multiple silver elements inside them to distribute the current evenly through the fuse.
If these fuses are running warm or even hot, I would be VERY concerned as to the load being drawn through them.
One other thing, frequent fuse failures can mean only one thing, bad wiring in the installation.

Does it concern anyone that, in order to replace a burned out fuse in this panel, you have to open some type of main disconnect (also a fairly frightening-looking device, I'm sure) ahead of this panel and kill all these circuits?

Only a person intent on committing suicide would try to replace a fuse while this panel is energized.

AGREED! If this panel runs hot enough that the door has to be left open, there are serious problems here. Many years ago, I saw a large fuse panel in a theater projection room where the entire panel front was removed due to the intense heat inside - you could literally feel the heat radiating from the panel as you passed in front of it. A middle-of-the-night electrical fire was the eventual outcome.

Mike (mamills)

Mike: (Trumpy); mamils snuck in above
Panelboards like the one in the pics are not 'common'...but there are still some around. Probably from the 1940-1950 eras.
Not 'home made'; this area was Federal Pacific, Westinghouse, Colton (local), Gavin-Graham,and a few other 'local' panelboard mfgs.

As I mentioned above, the 'heating' problems usually are from bad tension connections at the fuseholder clips. The tension knob devices in the pic, and the one laying at the bottom of the cabinet.

As to the bare buss, that's how it was; also the guage of the enclosure is probably double or more of today's enclosures.
John

In fairness to this situation ...

I have seen several similar installations. In each case, the equipment - usually an ordinary breaker panel, sometimes a motor starter enclosure with overload elements - was in an area where there was something else applying heat to the panel. For example, a nearby oven. This higher ambient resulted in false tripping, and the open cabinet / fan was a solution to that problem.

Mind you, I'm not defending the practice! It's just that you need to understand what the cause of the problem is, before you can try to fix it.

Even where allowed by the code, I try not to solve problems by using a larger breaker / fuse. Doing so seems to 'teach' the uninformed that big fuses are OK ... when that's not the case at all!

Mike, as to all that exposed stuff in the cabinet ... this is very common in equipment of that age. That panel was probably built before WW2.
Fuses such as these are often changed 'hot,' with the load disconnected. That's why we have fuse pullers!

Then again, some understand current rules to require locking out a breaker before changing a light bulb. Just goes to show you how much times have changed ....

(After all ... remember when ashtrays and lighters were common promotional give-aways?)

Hi Mike:

Like Reno said, this type of panel was fairly common construction back then. If used within its ratings and given even token attention to upkeep, it will outlast any of the junk made today. Heck, it already has come to think of it.

SEE THIS THREAD AND ITS MATES for more examples of the older style construction.

I think in part two I show the fuse holders and note how I think one would change the fuses "hot".



I've run into a few similar situations, and the main switchgear at Avalon (In a separate room downstairs, I didn't get pics) is a hodge-podge of old fuseholders and circuit breakers kludged into the framework (it was an open-switchboard design), it too let off a fair amount of heat walking near it.

One thing about your theatre panel quoted above...why did the fire happen in the middle of the night, when one would think the panel had less load on it? Do you have any more details about that incident?

Mxslick: Yeah, I know panels were made like this many years ago. Our Baptist church here (1926 vintage sanctuary) had two such panels - one very large one in the basement with numerous knife switches and fuseholders mounted on soapstone, marble(?), or some such non-conductive base, and a smaller panel near the sanctuary for controlling the lights (while singing "Nearer my God to Thee" for good measure). The construction work was as meticulous as it was deadly.

Concerning the theater fire, this happened about 30 years ago. I am also at a loss to understand why this would happen at a time of day when the load should have been less - no marquee lights, projector motors, sound equipment, auditorium and lobby lights, etc.
On many occasions when I would come in to open up, I would find numerous fuses so hot that they would burn my fingers. In addition, I could actually see some of the plug fuse elements showing a dull red glow in the dark - I never could understand this. Thinking this meant a bad fuse, I replaced it - same thing. I reported this to the manager several times and nothing was ever done. Even friends in the electrical business were unable to explain this situation. Everyone did agree that this was a potentially life-threatening condition.

Sorry to be getting off-topic...

Mike (mamills)

I'd date this as 1920's or 30's, probably not as late at the 1950's.

I don't think the white rope hanging down on the line side is asbestos wire, it looks more like some white rope/sash cord, possibly being blown sideways by the fan.

I am going to be honest here.

I have used a fan to keep some breakers from tripping.

I had a night time service call to a long existing grocery store, they had lost a couple of lighting circuits. Well I found the circuits had tripped but many of the other breakers in the panel where also warm.

A little checking with the amprobe showed all 20 amp lighting circuits to have at least 18 amps of load with a few over 20 amps.

So....out came the fan to keep the circuits on that night and the next day a crew was there breaking up the circuits.

Of course I did not leave any live parts exposed.

Bob, now that's the proper use of a fan to prevent a bad situation from getting worse! As a very temporary solution to keep a major client on-line, with the proper repairs done promptly.

The subject panel in this thread and the lame excuses provided by the building owner are, however, almost criminally dangerous.

Wow, Mike, now that's one for the electrical forensics file...either that or the building was haunted!! Don't think I'd ever seen a situation with glowing plug fuses..anyone else here seen such a thing? Wow.

MxSlick: This old theater may well have been wired by some ancient electrician who stayed around to haunt the joint. It had some very strange wiring. The main service equipment was located in a mechanical/air conditioning room at the back of the building. There were two enormous main EXO disconnects. I remember one contained three poles and three fuses, plus neutral. The other switch had three similar poles, but a single line/load conductor to only one fuse (?). I never did find out what kind of voltages were coming out of this stuff - it made me nervous to go anywhere near this mess. Both of these switches dumped their load conductors into a large wire gutter with more exo's than you could shake a stick at.

I wish I still had one of those strange glowing fuses. I don't even know who manufactured it. It had a glass body, and the small cardboard label that resides behind the fuse link was gone (burned away, maybe?). The only identifying mark was a "30" stamped into the center contact.

Mike (mamills)

call me an idiot, but whats exo.....im just losing my mind, so help me find it....lol

Hi KJ: I always thought it meant an EXternally Operable switch, aka a Safety Switch. Someone please correct me if I'm mistaken.

Mike (mamills)

I've seen those called EPOs, Emergency Power Off

oh.....duh.
told ya i was losin it.....
amazing what many years of brain cell destruction has done.....

Aren't most electrical products rated to operate at 40-50*C ambient temp anyway? It's not like this fuse box is a PC or other sensitive electronic device.

If they are interrupting load, they are overloaded.... 'nuff said! Nice taps too.... BOOM!

Some people know just enough to be dangerous. The excuse sounds like something only an engineer could come up with. Seriously, I know some EE majors in class and they don't know JACK about being safe. I think I'm the only one in class besides the prof that knows what NEC stands for. LOL!

This reminds me of a subject which came up on the (British) I.E.E. forum a short while ago.

Modern distribution panels here tend to have the terminals and busbars covered up to a much greater degree than present-day American equipment. Older panels were much more exposed though. Somebody was suggesting that an old Crabtree C50 breaker panel (typical 1970s commercial) should warrant at least a "code 2" on an inspection (meaning requires improvement) due to the exposed busbars inside. Somebody else was absolutely insistent that it should be "code 1," meaning immediate attention required, and that it should be replaced as a matter of urgency.

The fact is, so long as all the energized terminals and busbars are enclosed when the cover is in place those older panels are still perfectly in accordance with regulations today.

Quick jump in,

My Trains have a 240v three phase supply that runs the length of the train. It is protected by a 50 amp three pole breaker at the car with the generator. It lives in a raintite box under the car.

In the summer, when ambient approaches 90, and the sun is beating on the box that the car knockers have painted black, the breaker trips cause it dang well feels like it. Because of where it lives and it's 90 degree trip, ambient air temp trips it, rather than overcurrent. I am not far from putting equipment fans in the box to cool it off. With maybe a duct to pull the air over the ice box first.

TW

never underestimate the perversity of an inanimate object.

I'm an EE major (I've since graduated as a BSEE). Realize that we get taught mathematical and physics theory. And the idea that something that once functioned can fail is rarely ever mentioned. And thus designing things to fail in a safe condition isn't mentioned. Most of the things EEs would ever work on are inside chips, and the currents are in microamps, and voltage rarely above 5V. Thus the problem you can get when a EE engineer starts to mess with house wiring, if he doesn't really comprehend what the equipment grounding conductor is really for. I knew someone who bought an older house that had two wire romex without the ground, and he replaced the outlets with 3 prongers. He just strapped the neutral to the ground, figuring that would be okay as both are at zero volts. "What if that neutral goes open, then the computer will end up riding on 120VAC on its case?". Something he hadn't thought of.

And of course "NEC" is the name of a Japanese comsumer products company..

Hardwareguy, I have seen this situation, where the ambient was high enough to matter. For example, where the panel supplied an oven's heating elements. It's rather annoying to watch 30 amps of current blow a 50 amp fuse! It's usually in such a location where I find such open panels.

Some guys get fancier, and mount little fans to the side of the enclosure. I have even seen outdoor switchgear with roof 'turbine' fans mounted on them. While this is considered a listing violation, it is an attempt to reduce the temperature inside the cabinet to something reasonable.

Wa2Wise, thx for the explanation of an EE's education. On my jobs, the engineer and I have an understanding ... he stays clear of the electric work, and I stay away from the bridge design

I have had Inspection allow supplemental cooling but im in Canada so...We were told to contact the whosalers\manufacturers to find the solution then call inspection back for special permission.They also mentioned that up to 33% in increase o\l capacity could be achived.I have also heard they run compressed air though the MCC's in the Windsor saltmines.If no kits or other viable oppions exist the inspectors wont sign off on it and a work order is issued to replace it.They cant modify performance of equipment without approval or insurance can and will drop them.They have no insurance if that hurts somone.

So are we talking like a panel in a commercial kitchen where there is a panel right above or beside a hot oven and the ambient temp at the panel is around 150*F?

If so, that would explain the large breaker in the panel and the much smaller fuse on the oven. I saw this done at the pizza place where a couple of my friends worked. The area where the panel was was probably too hot to touch.

I suppose such a situation might arise where a panel was behind a pizza oven .... but that's not on my list of situations I've actually seen.

#1 was in a hot dog factory, where the panel controlled the sundry motors that moved the sausages through the 'oven' ... a 100 ft long tunnel with conveyor drives, steam injectors, smoke generators, water chillers, etc.

#2 was in a factory that made plastic boxes, and the heat was from the forming process .... it takes quite a while for plastic to cool. The panel was heated by finished product, as it was transported past the panel.

#3 was a place that made diving boards for the Olympics. There, the panel in question was between the powdercoat oven and the anodizing tank ... if they both were operating, there was a lot of heat in that corner.

#4 was the motor controllers at the top of a tower in a dog food factory. While the equipment was on the roof, between the summer sun and the heat from the tower (metal hard hats were needed, as plastic ones got soft) ... the motor starter heaters were already the largest made for that size of starter.

Another variation is when a fan is directed at a single-phase motor that has internal overload protection.

Damn! I wondered what those things were.

Somehow I ended up with some of those in my warehouse an nobody knew what they were.

Thanks

Nice pic BTW The fuse test light is a classic!

I have today had a most interesting lesson that relates to this discussion.
I work for a company that manufactures and distributes switchboards and componentry, including fuselinks. We have just received a shipment of fuselinks from a new supplier, and my job was to quality check them. One of the things that I got to check was how close to the published time/current curves these fuses were.
15A fuses were tested, firstly at 40A (near-instant blow), then at 30A (22Secs), then at 25A (11m 40s), then finally at 20A (> 4 hrs). These were very much according to expectations. The interesting thing was just how hot the fuse got at 20A. The whole office smelt strongly of frying fuse!The fuse was way too hot to touch, I would estimate it at around 120 deg C. Yet even after 4 hours of this torture, it was still hanging in there. I am told that this is entirely normal behaviour.
The point I am making here is that if the fuse board at the kick-off of this thread needed fan-cooling to stop the fuses from popping, they were not just passing rated current, but more probably a good 25% overload! Methinks that this cannot possibly be a good thing, no matter how you look at it.

Exactly. And since wiring as old as what is most likely in that panel is good for 60 deg. C anyways, it's only a matter of time before a serious fire results. If the fuses, are getting cooling from the fan, the wiring behind the front is not getting any cooling at all.

Interesting; I have never done the sort of testing you describe.

In the situations I have encountered, momentary amp readings showed current loads well under the rating of the fuse / breaker, yet there was that tripping problem, that was attributed to the ambient temp.

"Attributed" is the key here; perhaps I need to hook up a recording type of instrument to monitor the load at the time it trips. That is, if I ever encounter this again

I did some more fuse testing today, and I have given the graphs to Trumpy to post for me.
I tested the 15A fuselink (a 22mm dia x 58mm barrel fuse) for temperature rise, first at 15A, and then at 20A. I had a temperature probe snuggled up against the barrel of the fuse, this being inside a fuseholder of the correct type for the fuse. This completely shrouds the fuse in a plastic case.
At 15A, the temperature rose to 55 deg C and held there, from a starting temp of 20deg C. This is within the allowable limit of no more than 40 Deg C rise at rated current.
The eye-opener was the 20A test. The temperature quickly climbed past 100 deg C and levelled out at 135 deg C! No wonder it made the office smell of frying fuse. One can only wonder just how close the fan-cooled fuseboard was to starting an electrical fire.
For anyone wondering about the test set used for these tests, here is a quick description : we have a 10A variac which plugs into a 240V mains socket. This feeds a transformer-type 140A arc welder which acts as the current source. The fuse (or breaker - we test them too) is connected as a short-circuit across the output of the welder with some nice fat 25mm2 cables we made up. A clamp-type multimeter provides ameans to measure the current. This setup lets us generate test currents of a little over 100A for short periods, and 50-60A all day long. A test current of 20A for today's test required the variac to be turned up to about 55V into the primary of the welder.

Here we go Mark, sorry about the delay:

This is interesting because I never really imagined that a there was that much of a temperature rise on a fuse or circuit breaker. I've heard numerous stories of "hot CBs" but just how hot has never been put into numbers.

A little anecdote: Based on what I've seen here I did an improv test where I found a small 2A fast-acting cartridge fuse. I ran it at about 2.05 amps AC for ten minutes, and sitting in free air it got up to 122 degrees as measured with a little wire thermocouple. I could see the fuse-link elongate and bow with the heat, but it never blew.

-John