screw-type fuse box

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  #1  
Old 05-07-05, 11:12 AM
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Unhappy screw-type fuse box

hi any ideas??

I have a lake-side camp(meaning anybody and any which-way :-) ) that has an old style fuse box leading to a hot water heater. I,ve not had trouble for 5years, however last spring on opening day I observed, an attempt, at a connection in the box, to ignite. eeeeks!
close inspection revealed coroded wire and clamping assembly, and screw. Resistance?? thereby creating heat like a toaster?? solution-- buy new box and replace all wiring after scraping the leads back to the connections as it is. BUT, The output of the box is 210, and it looks like (2) 110 feeds are the source. MY confusion is, the left clamping assembly, takes the black wire and sends the white wire to the right side asembly. thats 1 of the two feeds. the other does the same thing, sending the white wire to the left clamping assembly. Is this in effect cancelling the nuetrual , leaving both black wires for my 220?? oh yes there are bare copper to the grounding clamp.

thanks in advance for any response
 
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  #2  
Old 05-07-05, 11:44 AM
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I didn't understand what you said, but somebody else will. Stand by and I'm sure someone else will have some comments for you.
 
  #3  
Old 05-07-05, 01:12 PM
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hmmm.......I think you may have lost me as well.....from what I can gather you had a issue with arcing due to the buildup and possible oxidation and so on on the knife terminals of the old disconnect and now you have scrapped off the excess buildup and reduced the resistanace which was causing the arcing and excessive circuit resistance....whew..lol.....got that out...NOW...

On the second part I am not sure I follow........Is this what you are saying...

The black and white wire coming in is taken to the first terminal and then it is jumped with a wire over to the second terminal.....

Now.........are you sure you are not confusing the Line and Load sides up here on the connections....you will need to redescribe this a bit.....now....look at the wires coming into the box.....let us know if you have two seperate cables or pipes coming into the box and describe the wires in detail that come from each one....not in total as you did....describe each one as they enter the disconnect ....

Also since you are using a meter to read voltage as you have listed you have 220...probably nominal and actual reading voltage from the meter....you need to read the voltage across the black and white that enter into the box from the panel.....those should be your line voltage....if you read that as the 220 between those then those are you line.....you should get nothing on the other (2) going to the water heater if the disconnect is off....

again try to issolate the (2) wires that FEED the disconnect from the panel first.....and read the voltage on those....and post back....I am sure others here will chime in and help....

Again I could be reading it wrong so I figured I would give it a shot.....lol....
 
  #4  
Old 05-07-05, 02:16 PM
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For a true 220V circuit,

all you need are two hot wires (your black and white) and a ground. There is no nuetral wire needed in the setup.

Dryers and stoves use a combination of 110 and 220, which is why they have a nuetral connection. (Two hots, a nuetral, and a ground for the new 4 wire ones, two hots and a nuetral for older 3 wire setups)

Hope this helps!
 
  #5  
Old 05-07-05, 05:15 PM
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I think I may know what you are saying. Well, I'll at least hazard a guess.

Are you saying that this is wired with 2 normal 120 volt circuits, each containing a hot and a neutral, and that the neutrals are connected together at the box you need to replace, and that only the two black wires go to the water heater? Can you tell where these two cable assemblies come from, and where the black and white wires are connected?

As has been described above, a true 240 volt appliance (and an electric water heater is one) needs no neutral. It needs to be fed with both hot wires from your panel, coming from different sides of the 240 volt source.

Regardless of what you actually have, your water heater needs no neutral. All you need are the two hot wires and a ground. The two hot wires must be properly connected and fused appropriately.
 
  #6  
Old 05-09-05, 08:24 AM
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sorry

I know its confusing. yes, the two black wires are 2 separate110 circuits.
You guys are right,no neutrals are needed Maybe the person that installed this old screw type fuse-box did not know what to do with the white wire that was hanging around with the black one. When first installing the wiring, What would you do with the white wire?? pull it out of the sheathing or just dont connect either end?
thanx
 
  #7  
Old 05-09-05, 08:36 AM
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Do not attempt to pull a wire out of the sheathing. That usually doesn't work for anything except a real short length, and then you are modifying the cable, which is wrong.

You really don't want a cable that is not balanced with current flowing in both directions, and you have this if you only use one wire per cable.

The correct solution is to use a single piece of cable, and use the black wire for one hot and the white wire for the other hot. You then re-identify the white wire as hot with a black (or other preferably dark color) marker or a piece of electrical tape.
 
  #8  
Old 05-09-05, 11:52 AM
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thanx all

Guess what ill do is remove the two cables. replace with 12 guage cable connect black and white to the two hot bus bars(one to each) paint it black, run it to the screw in type fuse box, paint the other end and connect to the two separate clamps.
 
  #9  
Old 05-09-05, 12:09 PM
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Slow down there.

Are you certain that 12 gage wire is large enough? What size fuses are being used, and what are the current requirements for the unit?
 
  #10  
Old 05-10-05, 06:24 AM
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Mams,

Rac is correct in asking you that question because based on what you have posted it is possible the person before you may have run the lines like they did to have them in parallel.....might not but regardless you do need to make sure the 12 AWG wire is sized correct for your disconnect.

Do not try pulling out wires as if you determine you do not need them it is better to simply cap them off. However, as RAC said you need to make sure the wiring you are refering to will supply the equipment in question.
 
  #11  
Old 05-10-05, 08:08 AM
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awright, cap it off seems good and easier

the fuse box has (2) 20 amp fuses---1 for each line. wont 12 gage carry 20 amp??
mamsram
 
  #12  
Old 05-10-05, 08:18 AM
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Yes, 12 gage wires handles 20 amps.

My concern was that most water heaters are 30 amp. This must be a small water heater, which makes sense, as you are talking about a small cabin.

How long is this run of two cables where the neutrals don;t serve any purpose? I would rewire it so that only one of the cables is used (or install a new cable). I would then remove the not used cable(s).
 
  #13  
Old 05-11-05, 04:52 AM
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thanx Bob

I'll check the water heater amp just to make damn sure. Just thoght I would replace it with what was there. The water heater is approx. 10 ft. from the main, so I would say probably about a run of 15/16 ft. of wire.
 
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