wmartin@brl-tgr.ARPA (Will Martin ) (08/29/84)
I suspect that most people on the net are like me and know more of electronics than basic electrical (power) information. I hope someone out there has some practical electric wiring experience or knowledge and can answer this: How the rating for the "electrical service" to a house (or whatever) determined? For example, I have 60-amp cartridge fuses in carriers on the fuse panel where the electric lines come into my house. One of these carriers (which hold two fuses each) controls the line that is subdivided through a fuse panel to feed the household wiring. The other carrier controls the line that goes to an outlet for an electric stove, which we don't use, having a gas stove installed. So, all in all, there are four 60-amp fuses, one for each side of two lines. Do I have "60-amp service", "120-amp service", or "240-amp service" with this set up? When we use both a 220-volt window airconditioner and an electric dryer, we are constantly blowing one of these 60-amp cartridge fuses. I believe this is because the rest of the house wiring is installed "lopsidedly" -- all the heavy loads (freezer, dehumidifier, refrigerators, kitchen appliances, etc.) hung off one side of the main line, and the other side having only simple lights, clocks, radios, etc., and when the two major 220-vold loads draw power from both sides of the line, the one side is over-strained when a refrigerator compressor or something kicks on. I realize that this imbalance can be corrected by having an electrician swap some circuits in the distribution fuse panel. However, the fact that the cartridge fuse blows makes me wonder if the electrical service to the house is adequate. If this service is somehow currently divided between the whole-house wiring and the unused stove wiring, can the circuit now going to the stove outlet be used somehow to take some load off the other portion? Or would the wire leading into the house have to be replaced, and the 60-amp fuses and panel be replaced with larger fuses or circuit breakers? I seem to find it next to impossible to get an electrician to come to the house to give estimates and answer this sort of question, so I am turning to the net as the fountain of wisdom to enlighten my ignorance. Regards, Will Martin seismo!brl-bmd!wmartin or wmartin@almsa-1.ARPA
dcm@dmcnh.UUCP (08/31/84)
>I have 60-amp cartridge fuses in carriers >on the fuse panel where the electric lines come into my house. One >of these carriers (which hold two fuses each) controls the line >that is subdivided through a fuse panel to feed the household wiring. >The other carrier controls the line that goes to an outlet for an >electric stove, which we don't use, having a gas stove installed. > >So, all in all, there are four 60-amp fuses, one for each side of two >lines. Do I have "60-amp service", "120-amp service", or "240-amp >service" with this set up? > >When we use both a 220-volt window airconditioner and an electric >dryer, we are constantly blowing one of these 60-amp cartridge fuses. >I believe this is because the rest of the house wiring is installed >"lopsidedly" -- all the heavy loads (freezer, dehumidifier, refrigerators, >kitchen appliances, etc.) hung off one side of the main line, and >the other side having only simple lights, clocks, radios, etc., and >when the two major 220-vold loads draw power from both sides of the line, >the one side is over-strained when a refrigerator compressor or something >kicks on. > >I realize that this imbalance can be corrected by having an electrician >swap some circuits in the distribution fuse panel. However, the fact >that the cartridge fuse blows makes me wonder if the electrical service >to the house is adequate. If this service is somehow currently divided >between the whole-house wiring and the unused stove wiring, can the >circuit now going to the stove outlet be used somehow to take some >load off the other portion? Or would the wire leading into the house >have to be replaced, and the 60-amp fuses and panel be replaced with >larger fuses or circuit breakers? If you really can draw 60 amps from each pair of fuses, you have 120-amp service. It is possible that the stove is really downstream from the other fuses, in which case your service is only 60-amp and you will probably have to install new service from the street. It is also possible that the wires coming into the house are not really designed to take the load of both pairs of 60-amp fuses simultaneously. The wire size from the street is really the determining factor in the size of your service. You might be able to get the fuses to stop blowing by re-arranging the distribution of your circuits, but 60-amp service is not really large enough for the modern house's electrical requirements. If you really have 120-amps, you can probably get by with that, but you will still have to get your box re-wired or replaced. Dave McCracken Datamedia Corp., Nashua, NH. ..!decvax!ittvax!sii!dmcnh!dcm
moroney@jon.DEC (08/31/84)
According to the way your electrical fusebox is configured, you have 120 amp service. This is because the maximum current you can draw without blowing/swapping any fuses is 120 amps (60 for the electric stove circuit, 60 for the rest of the house) The two cartrige fuses in each line are not added together in the calculation since they are essentially in series when a 240 volt device is considered (current flow is through one fuse -> device -> second fuse). The fact you are blowing one of your cartridge fuses only means you are attempting to draw more than 60 amps through that particular fuse and since you don't have anything hooked up to the stove circuit, you are drawing 60 amps max. which is well under the 120 amp total limit for the wiring to the house. You can solve your problem simply by connecting the highest-drawing 240 volt device (probably your dryer) to the stove circuit and replacing the 60 amp cartridge fuse for the stove (now dryer) circuit with the proper size for it, probably 35 amps or so *IMPORTANT*. Since the dryer is no longer using the same 60 amp. service as the rest of the house, you should never have any more problems with the 60 amp cartridge fuse. You probably should balance the other devices while you are at it, but that is no longer as important. Mike Moroney ..!decvax!decwrl!dec-rhea!dec-jon!moroney
ron@brl-tgr.ARPA (Ron Natalie <ron>) (09/07/84)
If both 60 AMP main fuses were hooked up and the house corresponds to the electrical codes you should be able to draw 60 AMPs from both. After all, that's what the fuses are there for, to keep you from drawing more than the service can handle. If the total service was less than 120 Amps you are inadequately protected. In this case, it would have been wiser to install a main fuse of the proper size for both circuits. -Ron
wmartin@brl-tgr.ARPA (Will Martin ) (09/10/84)
To all who have responded so far to this inquiry: Thanks much! I appreciate your taking the time to help. I have tried to send mail responses to each one of you who sent me an individual message, but I have recently run into a batch of messages for which my host's mailer generated bogus reply addresses. See my submission to net.mail about this problem if you care about such things. So, if you didn't get a reply, my apologies -- I have read and saved each response. Thanks again. Will Martin seismo!brl-bmd!wmartin or wmartin@almsa-1.ARPA