wmartin@brl-tgr.ARPA (Will Martin ) (11/08/85)
I'm too dumb to know the answer to this, but at least I'm smart enough to ask for the answer, rather than trying it to see what will happen! :-) I have large cartridge fuses at the main power input to my house electrical circuits. If I blow these fuses, and replace them with copper rods, what is the next stage of fusing/protection/damage? I can think of several possibilities: 1) The meter outside the house has some sort of built-in fusing, which will blow. 2) The wire(s) from the pole to the house will melt or burn. 3) The transformer on the pole, serving several houses, has some form of fusing or circuit breaker, which will trip or blow. 4) The transformer on the pole, itself, will expire. Which of these, if any, will happen? Thanks for responses! Will Martin UUCP/USENET: seismo!brl-bmd!wmartin or ARPA/MILNET: wmartin@almsa-1.ARPA
ron@brl-sem.ARPA (Ron Natalie <ron>) (11/08/85)
> I have large cartridge fuses at the main power input to my house > electrical circuits. If I blow these fuses, and replace them with copper > rods, what is the next stage of fusing/protection/damage? > > I can think of several possibilities: > 5) The wire between the main fuses and your fusebox may melt. (just another possibility) -Ron
sgcpal@watdcsu.UUCP (P.A. Layman [EE-SiDIC]) (11/11/85)
In article <2980@brl-tgr.ARPA> wmartin@brl-tgr.ARPA (Will Martin ) writes: >I have large cartridge fuses at the main power input to my house >electrical circuits. If I blow these fuses, and replace them with copper >rods, what is the next stage of fusing/protection/damage? > >I can think of several possibilities: > >1) The meter outside the house has some sort of built-in fusing, which >will blow. No. The meter has no internal fusing. >2) The wire(s) from the pole to the house will melt or burn. This is one real possibility. See explanation below. >3) The transformer on the pole, serving several houses, has some form of >fusing or circuit breaker, which will trip or blow. No. Again it is unlikely to have any fusing. >4) The transformer on the pole, itself, will expire. No. The wire to your house will act like a fuse before this happens. >Which of these, if any, will happen? Thanks for responses! The fusing you are speaking of is intended to protect the wires to your house, through the meter, and up to the breaker or fuse panel for individual home circuits. Ideally fusing is placed at the cicuit feed point. As this is not practical or convienient, it is placed in your home. Provided any failure occurs past the fusing it provides the same degree of protection as being located on the pole. However it does not protect against failures between the pole and the fusing. If you replace the fusing with copper pipes etc., you are violating a number of elctrical codes. You would likely be responsible for any damage that occurs to the wires from the pole to your house. It is also probable that your insurance will not cover any firethat might result from the lack of proper fusing. I would suggest that you pick up some spare fuses instead. If they blow frequently it indicates some other problem exists and that it should be rectified instead. Paul L.
hr@uicsl.UUCP (11/11/85)
RE:
"If I blow these fuses, and replace them with copper
rods, what is the next stage of fusing/protection/damage?"
You might consider looking the other direction. Assuming there are no
further fuses/breakers downstream, a good short might melt the house
wiring. If the wires inside your house melt, the house could melt too!
harold ravlin
{ihnp4,pur-ee}!uiucdcs!uicsl!hrjvz@ccice5.UUCP (John V. Zambito) (11/12/85)
In article <2980@brl-tgr.ARPA> wmartin@brl-tgr.ARPA (Will Martin ) writes: >I'm too dumb to know the answer to this, but at least I'm smart enough >to ask for the answer, rather than trying it to see what will happen! :-) > >I have large cartridge fuses at the main power input to my house >electrical circuits. If I blow these fuses, and replace them with copper >rods, what is the next stage of fusing/protection/damage? > >I can think of several possibilities: > >Which of these, if any, will happen? Thanks for responses! > >Will Martin > 6) (somebody else already said 5) Most likely, if something in the house were to consume massive amounts of power ( greater than 2,000 watts ), the wiring in the walls would glow bright red and start the house on fire. jvz@ccice5
bcbell@inmet.UUCP (11/12/85)
** power line ** Sorta depends on where you decide to short it out. If you shorted right at the main your local transformer's fuse would blow. This will result in a (very) load bang, amazing your friends, and disgruntling your neighbors, whose power will be off until the fuse is replaced. There's a lot of power here, so it might not blow at all. I've vaporized an allen wrench by mistake once by getting across the main. The pole fuse didn't even blow. R.M. Mottola Cyborg Corp. Newton, MA.
ewa@sdcc3.UUCP (Eric Anderson) (11/12/85)
In article <499@brl-sem.ARPA> ron@brl-sem.ARPA (Ron Natalie <ron>) writes: >> I have large cartridge fuses at the main power input to my house >> electrical circuits. If I blow these fuses, and replace them with copper >> rods, what is the next stage of fusing/protection/damage? >5) The wire between the main fuses and your fusebox may melt. Most likely, whatever is causing the short will fuse, assuming it is an appliance or something, because the wiring inside the house is of a lesser guage than that from the fusebox to the grid. The only case that would cause anything outside of the house/fusebox to fuse would be if the fusebox itself were shorted with larger conductors than those that fed it. Experience dictates that the narrowest conductor (impedence comes into play if different materials are used) will fuse, because the current being constant, will have the greatest density of flow through the narrowest section of wire. Eric Anderson, UC San Diego {elsewhere}!ihnp4!ucbvax!sdcsvax!sdcc3!ewa Home: (619)453-7315 Work: (619)586-1201 White House: (202)456-1414
dave@rocksvax.FUN (Dave Sewhuk,840-5H,76248,2883513) (11/12/85)
I would add the more probable answer.... 5) house will burn.
crs@lanl.ARPA (11/13/85)
> >I have large cartridge fuses at the main power input to my house > >electrical circuits. If I blow these fuses, and replace them with copper > >rods, what is the next stage of fusing/protection/damage? > > . > > . > > . > > 6) (somebody else already said 5) Most likely, if something in the house > were to consume massive amounts of power ( greater than 2,000 watts ), the > wiring in the walls would glow bright red and start the house on fire. > > jvz@ccice5 Must be a typo above. Ironing clothes typically consumes close to 2000 watts. It is not clear, to me at least, if the smaller fuses (or circuit breakers) down stream from these cartridge fuses are intact. I don't recall and don't have the original posting. If so, the fault would have to be between them and the cartridge fuses mentioned above, otherwise, the small fuses/circuit breakers would still provide protection. If the fault *is* between the small and the "replaced" large, fuses, I don't know because I don't know if the power company uses any protective devices upstream from the customer's fuse box. If not, it would be the wiring upstream of the fault that overheats. -- All opinions are mine alone... Charlie Sorsby ...!{cmcl2,ihnp4,...}!lanl!crs crs@lanl.arpa
ged@astroatc.UUCP (11/13/85)
In article <1863@watdcsu.UUCP> sgcpal@watdcsu.UUCP (P.A. Layman [EE-SiDIC]) writes: >>3) The transformer on the pole, serving several houses, has some form of >>fusing or circuit breaker, which will trip or blow. > >No. Again it is unlikely to have any fusing. On the contrary, pole transformers invariably have fuses or (on newer units) circuit breakers. However, since they are sized to protect the transformer itself, which the original article pointed out serves several houses, they don't protect houses or pole-to-house wiring very well. Greg Astronautics Technology Center
ornitz@kodak.UUCP (barry ornitz) (11/15/85)
Most residential pole transformers have both a fuse in the high voltage
primary and a combination disconnect/circuit breaker in the secondary
supplying the users. These are not the most reliable devices, however.
Their current ratings are also often many times higher than the service
drop to an individual house can carry [one transformer serves several
houses]. As stated in many of the replies, if the main fuses to a home
are blowing, there is likely a serious problem that needs to be corrected.
A fire caused by overloaded house wiring is much more likely to occur
than blowing a transformer overload device.
Barry L. Ornitz
Eastman Chemicals Division Research
Kingsport, TN 37664wmartin@brl-tgr.ARPA (Will Martin ) (11/20/85)
Thanks for all the posted and mailed responses on this subject! I'd like to emphasize (which I thought I did in the original by stating that I wouldn't actually DO this, and labelling the question "dumb" to begin with) that I have no intention of actually shorting any fusing in my power circuits. However, I am sure that it does happen by accident (debris falling during fires or storms comes to mind) and I wondered what would happen in that case. As I mentioned to a couple mail correspondents, one of my main 60-amp cartridge fuses blows fairly often, though my 15-amp individual-circuit fuses just about never blow. It is probably due to an imbalanced load situation, with too many high-wattage requirements loading one side of the 3-wire 220-V service, and I intend to have an electrician fix this. I posted the query because I started thinking about just what those 60-amp fuses were protecting. It can't be the house wiring, because the individual line fuses were not getting too high a load on them. It had to be the pole-to-house or within-box or meter wiring, and I thank you all for the answers and discussions on this. Regards, Will