Well, there were LOTS of 200 amp fuse panels installed, and I have a
100 amp fuse panel innmy house. Fuses are a lot more reliable than breakers. Fewer "nuisance trips", although fuses can fail from age/heat cycling/fatigue - and virtually no chance of "sticking" and failing to trip when required. They are a nuiscnae when they do blow - you need to have the right value fuse within ready reach, and a flashlight next to the panel is always a good idea.
Fuses fail from age/temp cycling. Since the lights SOMETIMES worked, the fuse was not blown due to a short or overload - the fuse just "failed"
Don't raise alarms where none are warranted. If the box and wiring are in reasonably good shape, and the load is not over about 80% (70% is better) no problem.
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We rented a condo down in miami a few times and they left instructions to flip the breakers on for the hot water and the hvac when you arrived and flip them off when you left. I thought about telling them that was going to bite them but most people really don't like unsolicited advice.
SOME breakers ARE rated to use as switches. MANY industrial/commercial installations have no light switches - the lighting circuits are controlled by the circuit breakers in the sub-panels. Breakers designed for this service are identified with a label reading "swd" for "switch duty". There are also "fld" breakers designed to SWITCH Flourescent lighting loads.
A "swd" breaker for the hot water would be quite acceptable.
In the past HVAC units would use a "HACR" breaker. - but virtually all normal breakers today pass the test for the old "hacr" standard - so a "swd" breaker could be used for the AC too.
MOST GOOD breakers today are SWD, and many are also FLD
You beat me to it. I've installed breaker panels in commercial and industrial settings where the electrical designer specifies switch rated breakers because that's where banks of lights are controlled. Like a department store where row after row of lights are switched once a day or never in case of a 24 hour business. What I'm seeing now in a lot of retail outlets is the incorporation of remote controlled switch banks connected to the company's computer network so the main office can monitor and control lighting. It's a pretty cool setup.
TDD
I heard banjo music when the page came up. 8-)
TDD
ide quoted text -
With the color of the shack, there were probably two hispanic extended families living there.
The lights may sometimes work because they are powered from the other leg through a 220V load like a water heater.
I would not bet that the fuse "just failed".
A loose connection near the fuse can generate heat to blow the fuse at lower than its rated current. With a loose connection you may see flickering lights.
I have seen many fuses "just fail" over the last 50 years, both automotive and "mains". And like incandescent (filament) lamps, I've seen them "mend" themselves temporarily - sometimes several times, before final total failure. An intermittent "failed" fuse can really be a bugger when troubleshooting an intermittent electrical problem.
Further investigation is going to be necessary, because last night I did notice that lights were dimming, almost imperceptibly. And not necessarily just the ones on the aforementioned affected outlets.
I beg to differ. The fuses can arc weld themselves back together and work for a while, then re-fracture. Depending on temperature changes etc, this MAY happen more than once, but even once is a rare occurrence. Rare, but it happens.
On most current automotive fuse boxes there are no "connections" behind the fusebox that would be influenced by removing the fuse. - and replacing the fuse invariably solves the problem - often for the remaining life of the vehicle.
Same thing happens in fused distribution panels - both with plug fuses (the round glass screw-in common fuse) and with cartridge fuses, on occaision. Bump the fuse, or have the temperature go up a few degrees, and the fuse makes contact again, allowing light loads to operate. Sometimes they will "weld" themselves and not cause a problem again for several days. Looking at the fuse there is no sign that there is anything wrong - but sometimes if you tap the fuse in the dark you will see a faint blue arc inside the fuse body, and a light connected to the circuit will either flicker off, or faintly flicker on..
In automotive systems., I have seen it much more often in the old tubular fuses than it the ATO type - but I've seen it with an ATO as well. Nothing like seeing the failure LED on an indicator type fuse flicker randomly in the fusebox when you are trying to trace down an intermittent electrical problem. Since most automotive fuses are NOT indicator fuses, the cause is not often as obvious as the intermittent radio problem on that car.
But wait...The other thing missing is the gas engine powered Maytag washer that such an upscale mansion would have.
Joe
A lot of circuit breakers are specifically rated for switching duty, and it is very common in industrial facilities like warehouses for the circuit breakers to double as the light switches.
I don't know how you can say that without examining the fuse close up. Sounds like it may have crumbled from excessive heating from carrying too much of a load. Only a hands-on inspection will determine that, and it would probably mean cutting open the fuse to determine the failure mode.
Jumpin I would say *exactly* the reverse is true when dealing a lethal entity like 240VAC where a main fuse has failed and with so many other unknowns. Not being concerned enough might lead to a similar set of circumstances where a badly manufactured Chinese replacement fuse FAILS to blow and there's a meltdown as a result. A blown fuse is a warning that something's wrong. Assuming it's just a failed fuse and moving on seems to be bordering on terribly careless. Each to his own, I guess.
FWIW, hearing about a fusebox in a home in this day and age raises an alarm in my head that there's a potential overload situation. While fuse panels of 200A certainly exist, every *residential* fuse panel I've ever seen in the NE USA was a four banger with 15A screw-ins and a 60A total rating. I realize that experience is terribly limited, but regardless, a blown main fuse is not something to take lightly.
I don't know what the rules are up in the "Great White Way" or in other parts of the US, but I assume one of the safety reasons for switching to breakers is that they are much harder to override with pennies or aluminum foil. Not sure what the NEC has to say about installing new 200A service with screw-in fuses in the USA and I certainly know that my limited experience does not even speak for the USA NE - just the houses whose panels I have seen. All I know is when a fuse protecting an entire incoming phase fails, an investigation is warranted to determine the cause. Assuming it's simply a bad fuse is bad troubleshooting.
In this case, caution is especially called for because we just don't have the information necessary from the OP to make a good call. We have no information at all about the daily peak load he's putting on the panel, either. We don't have a picture of the panel with the cover off, which can often tell you what kind of workmanship is involved or if the wiring is shoddy or deteriorating.
I recall seeing one poster here show us a picture of his circuit box with all of the single wires laid out as neatly as the strings of a harp! I had never seen and will probably never again see such incredibly precise work - I wish I could remember the dude's name - when you see workmanship like that, you can usually discount poor wiring - but I digress.
With all the unknowns, it seems far more prudent to raise a caution flag than to give him the green light and say "bad fuse, replace and fuggedaboutit." The part of this that really gives me pause is that he reported that it's an intermittent fault. Yes, fuses, light bulbs and most anything electrical can fail that way, but when a safety device fails, it's far more serious than a light bulb failure. When the fuse protecting an entire leg fails, I consider that especially serious because it can easily indicate too much current is flowing through that leg, something that individual circuit fuses will not catch.
The truth is that we don't know a whit about either of those big IFS in this case. We don't know how well the loads are balanced in the house - many times one leg is bearing much more of the load than the other. That can be simply plugging in space heaters into the "wrong" outlets. In a house with a bigger circuit panel than the feeders dictate, that can happen easily. I've seen more than one "heavy up" that didn't include an appropriate upgrade from the feeder.
All we know here is that one leg of the incoming power lines had an intermittent, not quite completely failed fuse. We know very little else. (Since writing this, the OP has added a post indicating that he's got 200A circuit panel but we don't know if it's really 200A service or a 200A box sitting on 60A feeder lines.) With no ability to go onsite, we've got a barrel full of IFs that raise the caution flag.
Yes, I agree with you that fuses do fail from inherent vice but IMHO *every* fuse failure or circuit breaker pop warrants an investigation to find out what popped it. In this case, I would be looking at the total KWh's used monthly in relation to the size of the panel and also whether the panel was properly balanced with each leg carrying as close to half the load as possible. I'd turn everything in the house on and get out my tong meter to see what branch circuits were carrying in terms of load. I'd visually inspect the outside feeders to make sure they were sized for 200A and not 60 or 100.
IIRC, the panel should be sized so that even if every device in the house is running, the main fuse won't blow. I am not sure that's the case here. We also know fuses fail in multiple ways: in addition to failing intermittently or "popping" correctly in an overload, they can also fail to blow and thus not protect the wiring. That's an extremely hazardous situation.
If the two fuses for each leg are of the same vintage, I would replace both of them if I wasn't going to heavy up the panel and the load appeared to be well-balanced. My best guess, from the limited facts we've been presented, is that the load is too great for the panel and that one leg was carrying a heavier share of the load than the other, causing the fuse on that leg to deteriorate and partially fail.
But in reality, we don't even really know whether the fuse was bad. Replacing a fuse in a loose fuse holder could jiggle bad electrical connections just enough so that the intermittent disappears for a while. We can't know that unless somebody actually checks the dead fuse with an ohmmeter and carefully inspects the connections coming from the pole.
Running a cartridge fuse hot for a long enough time could easily cause serious deterioration. If that leg's overloaded, simply replacing the fuse could lead to tragedy, especially if the bad fuse is replaced with one that doesn't operate at its rated load, but higher than rated. And before you say that's unlikely, consider that you're the one saying we're dealing with a bad fuse to begin with. (-: Who's to say, without an examination, whether that intermittent fuse *should* have opened completely but didn't?
I've seen people ask very "shocking" questions, that indicate a lack of knowledge about electrical work. My favorite is whether it's OK to use a ground as a neutral. These kinds of comments lead me to almost always err on the side of caution when giving advice on the net, especially with things that have the lethality potential of possibly overloaded circuit panel. There's almost *never* enough information given by the OP to make a clear call. That's just the nature of Usenet.
In my limited experience, it's far too common for people to add circuits without thinking about the total load. I'm partially guilty of that crime. I've added the skinny "two in one" breakers to my house that have the potential to overload the main fuse if I run every circuit to capacity. I definitely should have heavied up the incoming feeders to meet code but I added the new circuits not to draw more juice, but to replace the old cloth covered circuits one-by-one with 12/2 romex w/ground and GFCI protection.
I left the all the old circuits in place because they serve porch and overhead lights that would have required major demolition to replace. Now, almost all the large loads like space heaters and window ACs run off 20A grounded circuits. I've got sensors on the incoming feeders that connect to my HomeVision controller to let me know the overall current draw on each phase. I used that information to switch circuits around until they were balanced, at least for the static large loads. I monitor it periodically to ensure the loads have stayed balanced.
I have a lot more breakers than I should, but the overall load has not changed - it's just been redistributed and rebalanced so each leg shares the load as well as I could balance it. The only difference in the overall load occurs at peak cooking times. One of the reasons for the rewire was to add an XTB coupler/repeater/amp for my X-10 stuff, and more importantly, to be able to use the microwave, the toaster oven and the refrigerator in this 70 year old house without blowing a breaker. That's not going to put a strain on the main fuses for each incoming leg because the kitchen outlets are served by different phases, a trick I learned right here in AHR.
Unfortunately, that's not the case in many other installations where there are too many circuits drawing from one phase and overloading it. I don't think replacing a fuse is going to get the OP off the hook. It could still be something like a bad connection to the main feeder in the circuit panel that's heating up and heating the fuse, too. Again, only an on-site inspection will reveal things like that.
I hope the OP continues to post his progress in running the problem to ground. (Electrical pun!) My money's on something other than the fuse being defective. There's something rotten in Denmark (do we even know where the OP lives, BTW?).
-- Bobby G.
That's certainly my take on it, but there's always the possibility of "inherent vice." If it were my problem, I'd be examining that fuse with a both an ohm meter and a Dremel tool. I'd probably hook it up to an audible continuity meter with sturdy spring-type battery clamps connected to each end so I could shake it, pound it, put it in the freezer for a while and heat with a heat gun to see what, if anything, allowed current to pass before I sliced it open to see how cooked it was.
That's a very good point. With the high possibility that the fuse holder has metal parts with dissimilar coefficients of expansion, an intermittent based on changing temperatures from a loose connection is a very likely possibility, IMHO.
We had a disposal problem that only showed up in the spring and fall. It would kick off, and then restart, usually when you jiggled the switch. Turned out to be a bad backstab connection that flaked out every time it got suddenly cold outside (the switch and outlet is was linked to were on an outside north-facing wall). Since circuit panels are often located near outside walls and are typically not well insulated, I believe as you do that a loose connection to the fuse could be the real problem here. Especially now that the OP has reported that the lights are still flickering. That's no bad fuse, I'm afraid.
Hopefully the OP will keep us updated . . .
-- Bobby G.
In this case I'll have to agree. Replacing the fuse did not totally solve the problem, so the fuse was a symptom, not the cause.
You need a picture of mine? 22 circuits, one of which is a 30 amp 220 pullout, and the other is a 50 amp 220 pullout. Installed in 1978 when the house was built. It also has a fused disconnect for the central AC beside the panel
Other than the garage circuits, which I have blown numerous times with table saw, compressor, and various other "tools of high demand"I've only replaced 2 fuses in 29 years. One of which was DEFINITELY a simple fuse failure, and the second almost definitely (a lighting only circuit with less than 800 watts maximum load on a 15 amp fuse - which has not blown for the second time in more than 8 years.) It was cracked in the "blow zone", the crack not visible to the naked eye
The first fuse, which was intermittent, had failed where the fuse element contacts the threaded shell. The solder didn't fail, so it was not a loose or oveheated fuse - the fuse element just cracked, right next to the soldered joint. If the lights or TV were on for a while they'd start to flicker a bit, then go out. Turn them off for an hour and turn them back on, and they'de work. Being wired with aluminum wire, I checked every connection on the circuit before thinking to replace the fuse. All outlets are now CO-ALR devices. Maximum load at any time during the problem time was less than 300 watts. Max circuit load in previous 15 years or so? Who knows, but in the 8 years I'd owned the house not likely more than 1500 watts or so - back before we got the central vac it had likely run the vacuum a few times. That (replacement) fuse has been there now something like 10 or 12 years.
My panel looks about the same, as did virtually every panel my electrician father ever installed.
It is just as irresponsible to scare the guy into spending big bux to replace what may be a perfectly safe and serviceable fuse panel
Except in the case of cheap chinese automotive mini-fuses I've never seen or had first-hand knowlege of a fuse failing to blow. There was a whole batch of ATO fuses recalled by Princess Auto that were made in China with the element made of too heavy a guage material that would blow on a short circuit, but required over 300% of the rated current, IIRC..
A properly operating fuse does not "blow" as soon as it's rated current is reached. Generally a 25% overload should blow in less than
10 minutes. A 100% overload MAY take up to 4 or 5 minutes to blow the fuse, and still be operating "correctly".However, a BLOWN fuse, in my experience, is ALWAYS an open fuse, with enough metal melted out of the element to be both obvious and permanently disconnected.
A FAILED fuse, on the other hand, can be failed in such a way as to be visibly impossible to detect, and intermittent.
In a cartrige main fuse, of course, it is impossible to visibly inspect the fuse without dismantling it, although at least in years past, there were some that quite visibly changed colour when blown - and some had neon bulbs in them that glowed when the fuse was blown.
There was a line of pole fuses that also had the neon in them - the hydro crew could tell immediately if the feeder fuse on the pole was blown.
Quite possible - even iff that leg was never over 50 or 60% capacity. A good idea to check the load and load distribution? Most definitely. But don't condemn the panel or the installation without checking it first.
It now appears he still has flickering lights, so there is most likely a bad connection involved.
A whole lot more difficult to do and more unlikely with a fuse panel.
Not quite sure why the fuses with different sized cones, that did not allow a heavier fuse to be installed than the socket was designed for, never caught on. Likely because the American manufacturers took a "not invented here" attitude. (I believe it was a Canadian inovation)
Required by code in Canada - split countertop receptacles.
Well, when I start posting in Alt.Industrial.Repair I'll keep that in mind. (-:
I still think it's a bad idea for homeowners to use circuit breakers as switches because of even the small possibility that they are using older breakers that are not rated for switch duty.
Citing the existence of industrial breakers that can operate as switches probably isn't helpful for the majority of homeowners, because it gives someone who's probably got no way to determine whether his breaker is switch-rated a potentially false sense of security. While technically correct and even germane to the issue, I think its not quite right to compare an industrial circuit panel to a consumer panel. Given that houses often change owners quite a few times, it's likely the panel's original receipts and manuals are long gone. I am sure no one wants to do the home repair community a disservice by pointing out an exception that's mostly related to commercial wiring and could be very dangerous in a non-industrial setting.
I just looked at my 30+ year old breaker box and there are no external markings indicating any of the breakers is switch-rated. I'm betting that when I look through the pile of old breakers I pulled there will be no indication whatsoever regarding "switch ratings." It's why I'll reiterate that using a safety device as a control device is not a good thing to do. I'll add a caveat that "unless you are sure it is switch rated." I will also have to add that "The likelihood is that you'll actually have to pull the breaker and confirm it by model number and manufacturer's specs or by looking for the rating stamped somewhere on the device." That puts likelihood of proper confirmation of the breaker rating way outside the skill set of most condo renters who are told to "just flip the breaker."
Besides, I think it's *damn* good practice to actually *install* a switch if you need a switch, and to keep people out of circuit boxes as a general rule.
The bottom line is that it's probably NOT helpful to suggest that a person switching off the AC or the water heater via a breaker in their rented condo may be in the right because some industrial panels have breakers that can and do serve as switches.
Breakers not rated for switch use edge closer to failure the more often they are used as switches because they are subjected to wear they were not designed to bear. I'm certain of this because when Dad retired from the Navy's Material Science Division he went to work as a forensic engineer. The annals of fire litigation are filled with failed breakers, stuck Klixon's and any number of failed, bypassed or misused safety devices.
Somewhere I have pictures from his old cases about breakers and Klixon's recovered from fire scenes that were part of the circuit that should have tripped but didn't, leaving wires and electric furnace cores to overheat and burn. While this was twenty years ago, I recall clearly safety experts citing breakers being more likely to fail if they were also being used as switches. It sounds like in recognition of this constant misuse of a safety device that breaker makers changed their design to allow them to be used as control devices.
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