Increasing amps on main breaker

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  #1  
Old 06-15-06, 10:18 PM
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Question Increasing amps on main breaker

The sub panel says it is rated at 100 amps. The main breaker is a 70 amp breaker. Can I just install a 100 amp breaker and be okay?

Not having any real problems yet, but want to install some other items in the house (dishwasher, dryer, garbage disposal, etc.) I believe I have space for other breakers, but need to know if I can easily increase overall amps by simply replacing the main.

Thanks in advance.
 
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Old 06-15-06, 11:23 PM
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What is the size of the wires feeding the main breaker from the utility?

It is possible that the breaker was replaced in the past and only a 70A was in somebody's truck. I've seen it before and was able to just replace main fuses to restore full 100A service.

Normally, a 100A is a minimum for a dwelling.
 
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Old 06-16-06, 09:00 AM
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I will have to go back and look at the feed lines. This is an old house (1959). I think it must have been rewired at some time as the sub panel has circuit breakers, not fuses. If I remember right the outlets have three wire connectors.

You may be right, whoever installed the 70 may not have had a 100 amp breaker on the truck.

I was just looking and replacing the breaker was my first (easy) thought. I can't see where I would cause anything unsafe by doing it, of course, don't know if it will do any good either.

I will have to do a little more investigative work to see if I will be able to do what I need to in this subpanel or have to replace the panel to get what I need.
 
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Old 06-16-06, 10:37 AM
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Do not attempt to replace a main breaker yourself.

I say this for several reasons.

1) It may not be the right thing to do. The wires may not be capable of carrying 100 amps. They need to be identified as to size and composition.

2) The feed for the main breaker is always hot, unless the meter is pulled. Not knowing what you are doing can get yourself killed.
 
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Old 06-16-06, 02:19 PM
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Originally Posted by racraft
Do not attempt to replace a main breaker yourself.

I say this for several reasons.

1) It may not be the right thing to do. The wires may not be capable of carrying 100 amps. They need to be identified as to size and composition.

2) The feed for the main breaker is always hot, unless the meter is pulled. Not knowing what you are doing can get yourself killed.
1) True. Will have to look into that prior to making change. I haven't even pulled the cover yet to see what kind of wiring I will be working with. This post was just a bit of "thinking outloud."

2) True again. Rest a little easier...I know what I am doing...I have thirty years experiance in electronics and am quite aware of how electricity loves to find the shortest, least resistive path to ground. I will do all I can to ensure I am not that path!!

I really do appreciate your concern. I know there are those who would jump into this without much thought of the dangers involved, I am not one of those. I have done house wiring, to the box and will be running the wires needed to upgrade this house (per local code). There is going to be a 220 line needed to support a electric dryer and maybe a 110 line or two.

I know of the two phases coming into the box and that they are hot all the time. That the "legs" in the box are hot as long as the main is on and it is better to pull the main, test the legs before you even think about sticking your hands in there. I know the voltage isn't really the killer, it is the current and it takes less than one amp to kill......

Having said all of that, I hope you feel better about me doing this myself. If I were to replace the box, I would get the electric company to cut power to the house. Cause even if I didn't kill myself, my luck I would have to pay them for a transformer somewhere!!!
 
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Old 06-16-06, 10:46 PM
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Originally Posted by Trying2Help
...it is better to pull the main, test the legs before you even think about sticking your hands in there. ...
While you probably know what you meant, I'll clarify for others who read this. It is far better to turn OFF a main breaker than to remove (pull) it.
 
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Old 06-17-06, 05:00 AM
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Cool

Originally Posted by Trying2Help
1) I have thirty years experiance in electronics and am quite aware of how electricity loves to find the shortest, least resistive path to ground. I will do all I can to ensure I am not that path!!
Electricity doesn't take the path of least resistance, it takes ALL paths available to it, to get back to the source. Just because you may not be the "shortest, least resisitive path", if you are A path, you are asking for trouble....

You don't want to be A path at all.....
 
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