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Thread: Wires too short to reach new load center.

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    DIY Junior Member Mindz i's Avatar
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    Question Wires too short to reach new load center.

    I live in a mobile home and have a Zinco load center that's going on the fritz. It's currently 100 amps. I figure I might as well put in a 200 amp box since our house is 100, our shed is 50 and our a.c. is 50. The new box I'm looking at is 28.7 in tall. This will put it too close to the ground since our old box is only 13 in tall and the bottom is 18 in from the ground (pictures below) and NEC 550.32(F) requires that the bottom of the load center be 24 inches from the ground. I'll have to mount it on the backside of the pedestal opposite the meter (example below).

    Currently, the load center powers a lug box in the house, lug box in the shed and an A.C. The shed has a washer, dryer, some outlets and lights. The lug center in the house has 2 awg aluminum wire running from it to the load center. None of the conductors will reach to the new load center. I really, want to avoid running new conductors for everything. It would get really expensive.

    So, my questions are, can I extend the conductors by splicing? And which is best for a 2 awg conductor, splice bolts or a butt splice kit? Can I gut the current load center and use it as a junction box? If so, what kind of modifications would I have to make to the old load center to make it code compliant?

    Current load center. (basicly a 100 amp lug box) It was installed in 1983.



    Lug in house.


    Example of what neighboring houses did when upgraded. Different owners now.

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    Homeowner Thatguy's Avatar
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    Quote Originally Posted by Mindz i View Post
    The new box I'm looking at is 28.7 in tall. This will put it too close to the ground since our old box is only 13 in tall and the bottom is 18 in from the ground (pictures below) and NEC 550.32(F) requires that the bottom of the load center be 24 inches from the ground.
    So from connector to connector you need to add (29 + 24) - (13 + 18) = 22" of #2 aluminum?
    Last edited by Thatguy; 12-17-2010 at 11:37 AM.

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    Licensed Electrical Contractor Speedy Petey's Avatar
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    Electrical Contractor Jim Port's Avatar
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    Quote Originally Posted by Speedy Petey View Post
    The guy at NASA was busy preparing for a launch. Grin

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    Electrical Contractor Jim Port's Avatar
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    IMO upgrading to a 200 amp service would be a waste of money, especially for a manufactured home.

    Adding up the breakers like you did is not the proper way to size a service. A demand load calculation is the proper method.

    I have seen houses over 2k square foot that only needed a 30 amp 240 volt circuit for the A/C.

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    DIY Junior Member Mindz i's Avatar
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    The A.C. does state a 30 amp minimum. But a 50 amp maximum. We were going with 50 amps to play it on the safe side. Currently, we have a 40 amp breaker for the A.C. Most of the homes around here are upgrading to 200 amps. The Chief Electrical Inspector, if I understood him correctly, suggests upgrading to 200 amps.

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    Homeowner Thatguy's Avatar
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    Quote Originally Posted by Mindz i View Post
    The A.C. does state a 30 amp minimum. But a 50 amp maximum. We were going with 50 amps to play it on the safe side. Currently, we have a 40 amp breaker for the A.C. Most of the homes around here are upgrading to 200 amps. The Chief Electrical Inspector, if I understood him correctly, suggests upgrading to 200 amps.
    You can use your elec. meter and a clock as an ammeter. The formula is about 1/3 of the way into this link.
    http://en.wikipedia.org/wiki/Electricity_meter
    An oven, elec. dryer or water heater may each take 20 A or so. Elec. heat by itself might pull 100 A.
    But whatever current you draw the voltage drop across the connections should be less than 5% of so of the drop across the 24" of cable.

    Checking the neutral connection is a little more complicated.
    Last edited by Thatguy; 12-17-2010 at 02:25 PM.

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    DIY Junior Member Mindz i's Avatar
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    We couldn't now, given the condition of the current load center, use it to test how many amps we are pulling on average. We have tripped the 100 amp breaker several times over the years. If we run the washer, dryer, hotwater heater, dishwasher, A.C., 3 computers, Tv, fridge and several other items, we easily pull more than 100 amps. Our electric bill in the summer months is around $360 a month. Could you imagine the surprise when our recent bill was $45. I'm loving this for the time being. Kids are spending less time watching tv and on the computer. But, we will need to get this fixed before too long.

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    DIY Junior Member Mindz i's Avatar
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    Question

    The home has three 2awg aluminum wire going into the current load center. Two of them connect into the top of the hot bus bar and one into the neutral bus bar. A forth aluminum conductor, which is the ground or common, goes into the neutral bus bar from the house, as well. I'm not certain yet, what gauge it is. The bottom of the new load center will be 5 inches higher than the current one. Add in the fact that the new box is twice as tall and the main breaker is much higher within the new box, I will need about 24 more inches of 2awg wire added to each wire to reach the new breakers. Plus, around two more feet for the common. And that's just for the home.

    The wires coming from the shed and are smaller. They are 6awg conductors. There are 4 of them. I would have to add about 24 inches to all four of them. And the wires from the A.C. are 6awg. There are 3 of them. Again, I would have to add about 24 inches to each of them.

    So, my question is, can I splice them to extend them? Or am I required to run new conductors? And, which method is best? Butt splice kit or splice bolts. Also, can I gut (take out the bus bar and breakers) the current load center and use it as a junction box?

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    Homeowner Thatguy's Avatar
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    Quote Originally Posted by Mindz i View Post
    I will need about 24 more inches of 2awg wire added to each wire to reach the new breakers.
    24" of #2 alum is ~0.5 milliohms of resistance. If you turn on enough appliances in your house to pull 50 A then the voltage drop across the wire + connectors should be less than about 25 millivolts if your finished connections of whatever type have integrity.
    A DVM should be able to confirm this.

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